Space Network Time Distribution and Synchronization Protocol Development for Mars Proximity Link

NASA Technical Reports Server (NTRS)

Woo, Simon S.; Gao, Jay L.; Mills, David

2010-01-01

Time distribution and synchronization in deep space network are challenging due to long propagation delays, spacecraft movements, and relativistic effects. Further, the Network Time Protocol (NTP) designed for terrestrial networks may not work properly in space. In this work, we consider the time distribution protocol based on time message exchanges similar to Network Time Protocol (NTP). We present the Proximity-1 Space Link Interleaved Time Synchronization (PITS) algorithm that can work with the CCSDS Proximity-1 Space Data Link Protocol. The PITS algorithm provides faster time synchronization via two-way time transfer over proximity links, improves scalability as the number of spacecraft increase, lowers storage space requirement for collecting time samples, and is robust against packet loss and duplication which underlying protocol mechanisms provide.

Parallel-aware, dedicated job co-scheduling within/across symmetric multiprocessing nodes

DOEpatents

Jones, Terry R.; Watson, Pythagoras C.; Tuel, William; Brenner, Larry; ,Caffrey, Patrick; Fier, Jeffrey

2010-10-05

In a parallel computing environment comprising a network of SMP nodes each having at least one processor, a parallel-aware co-scheduling method and system for improving the performance and scalability of a dedicated parallel job having synchronizing collective operations. The method and system uses a global co-scheduler and an operating system kernel dispatcher adapted to coordinate interfering system and daemon activities on a node and across nodes to promote intra-node and inter-node overlap of said interfering system and daemon activities as well as intra-node and inter-node overlap of said synchronizing collective operations. In this manner, the impact of random short-lived interruptions, such as timer-decrement processing and periodic daemon activity, on synchronizing collective operations is minimized on large processor-count SPMD bulk-synchronous programming styles.

Modular Universal Scalable Ion-trap Quantum Computer

DTIC Science & Technology

2016-06-02

SECURITY CLASSIFICATION OF: The main goal of the original MUSIQC proposal was to construct and demonstrate a modular and universally- expandable ion...Distribution Unlimited UU UU UU UU 02-06-2016 1-Aug-2010 31-Jan-2016 Final Report: Modular Universal Scalable Ion-trap Quantum Computer The views...P.O. Box 12211 Research Triangle Park, NC 27709-2211 Ion trap quantum computation, scalable modular architectures REPORT DOCUMENTATION PAGE 11

pSCANNER: patient-centered Scalable National Network for Effectiveness Research

PubMed Central

Ohno-Machado, Lucila; Agha, Zia; Bell, Douglas S; Dahm, Lisa; Day, Michele E; Doctor, Jason N; Gabriel, Davera; Kahlon, Maninder K; Kim, Katherine K; Hogarth, Michael; Matheny, Michael E; Meeker, Daniella; Nebeker, Jonathan R

2014-01-01

This article describes the patient-centered Scalable National Network for Effectiveness Research (pSCANNER), which is part of the recently formed PCORnet, a national network composed of learning healthcare systems and patient-powered research networks funded by the Patient Centered Outcomes Research Institute (PCORI). It is designed to be a stakeholder-governed federated network that uses a distributed architecture to integrate data from three existing networks covering over 21 million patients in all 50 states: (1) VA Informatics and Computing Infrastructure (VINCI), with data from Veteran Health Administration's 151 inpatient and 909 ambulatory care and community-based outpatient clinics; (2) the University of California Research exchange (UC-ReX) network, with data from UC Davis, Irvine, Los Angeles, San Francisco, and San Diego; and (3) SCANNER, a consortium of UCSD, Tennessee VA, and three federally qualified health systems in the Los Angeles area supplemented with claims and health information exchange data, led by the University of Southern California. Initial use cases will focus on three conditions: (1) congestive heart failure; (2) Kawasaki disease; (3) obesity. Stakeholders, such as patients, clinicians, and health service researchers, will be engaged to prioritize research questions to be answered through the network. We will use a privacy-preserving distributed computation model with synchronous and asynchronous modes. The distributed system will be based on a common data model that allows the construction and evaluation of distributed multivariate models for a variety of statistical analyses. PMID:24780722

Cloud Computing in Support of Synchronized Disaster Response Operations

DTIC Science & Technology

2010-09-01

scalable, Web application based on cloud computing technologies to facilitate communication between a broad range of public and private entities without...requiring them to compromise security or competitive advantage. The proposed design applies the unique benefits of cloud computing architectures such as

Building Multicultural Awareness in University Students Using Synchronous Technology

ERIC Educational Resources Information Center

Stork, Michele Garabedian; Zhang, Jingshun; Wang, Charles Xiaoxue

2018-01-01

To explore the potential for building multicultural awareness in university students using synchronous technology, faculty members from an American regional state university and a Chinese regional university collaborated to find appropriate ways to integrate synchronous technology (e.g., Adobe Connect) into a teacher education program in the…

Evaluating and extending user-level fault tolerance in MPI applications

DOE PAGES

Laguna, Ignacio; Richards, David F.; Gamblin, Todd; ...

2016-01-11

The user-level failure mitigation (ULFM) interface has been proposed to provide fault-tolerant semantics in the Message Passing Interface (MPI). Previous work presented performance evaluations of ULFM; yet questions related to its programability and applicability, especially to non-trivial, bulk synchronous applications, remain unanswered. In this article, we present our experiences on using ULFM in a case study with a large, highly scalable, bulk synchronous molecular dynamics application to shed light on the advantages and difficulties of this interface to program fault-tolerant MPI applications. We found that, although ULFM is suitable for master–worker applications, it provides few benefits for more common bulkmore » synchronous MPI applications. Furthermore, to address these limitations, we introduce a new, simpler fault-tolerant interface for complex, bulk synchronous MPI programs with better applicability and support than ULFM for application-level recovery mechanisms, such as global rollback.« less

Polymorphous Computing Architectures

DTIC Science & Technology

2007-12-12

provide a multiprocessor implementation. In this work, we introduce the Atomos transactional programming language, which is the first to include...implicit transactions, strong atomicity, and a scalable multiprocessor implementation [47]. Atomos is derived from Java, but replaces its synchronization...and conditional waiting constructs with transactional alternatives. The Atomos conditional waiting proposal is tailored to allow efficient

Scalable and Resilient Middleware to Handle Information Exchange during Environment Crisis

NASA Astrophysics Data System (ADS)

Tao, R.; Poslad, S.; Moßgraber, J.; Middleton, S.; Hammitzsch, M.

2012-04-01

The EU FP7 TRIDEC project focuses on enabling real-time, intelligent, information management of collaborative, complex, critical decision processes for earth management. A key challenge is to promote a communication infrastructure to facilitate interoperable environment information services during environment events and crises such as tsunamis and drilling, during which increasing volumes and dimensionality of disparate information sources, including sensor-based and human-based ones, can result, and need to be managed. Such a system needs to support: scalable, distributed messaging; asynchronous messaging; open messaging to handling changing clients such as new and retired automated system and human information sources becoming online or offline; flexible data filtering, and heterogeneous access networks (e.g., GSM, WLAN and LAN). In addition, the system needs to be resilient to handle the ICT system failures, e.g. failure, degradation and overloads, during environment events. There are several system middleware choices for TRIDEC based upon a Service-oriented-architecture (SOA), Event-driven-Architecture (EDA), Cloud Computing, and Enterprise Service Bus (ESB). In an SOA, everything is a service (e.g. data access, processing and exchange); clients can request on demand or subscribe to services registered by providers; more often interaction is synchronous. In an EDA system, events that represent significant changes in state can be processed simply, or as streams or more complexly. Cloud computing is a virtualization, interoperable and elastic resource allocation model. An ESB, a fundamental component for enterprise messaging, supports synchronous and asynchronous message exchange models and has inbuilt resilience against ICT failure. Our middleware proposal is an ESB based hybrid architecture model: an SOA extension supports more synchronous workflows; EDA assists the ESB to handle more complex event processing; Cloud computing can be used to increase and decrease the ESB resources on demand. To reify this hybrid ESB centric architecture, we will adopt two complementary approaches: an open source one for scalability and resilience improvement while a commercial one can be used for ultra-speed messaging, whilst we can bridge between these two to support interoperability. In TRIDEC, to manage such a hybrid messaging system, overlay and underlay management techniques will be adopted. The managers (both global and local) will collect, store and update status information (e.g. CPU utilization, free space, number of clients) and balance the usage, throughput, and delays to improve resilience and scalability. The expected resilience improvement includes dynamic failover, self-healing, pre-emptive load balancing, and bottleneck prediction while the expected improvement for scalability includes capacity estimation, Http Bridge, and automatic configuration and reconfiguration (e.g. add or delete clients and servers).

System Synchronizes Recordings from Separated Video Cameras

NASA Technical Reports Server (NTRS)

Nail, William; Nail, William L.; Nail, Jasper M.; Le, Doung T.

2009-01-01

A system of electronic hardware and software for synchronizing recordings from multiple, physically separated video cameras is being developed, primarily for use in multiple-look-angle video production. The system, the time code used in the system, and the underlying method of synchronization upon which the design of the system is based are denoted generally by the term "Geo-TimeCode(TradeMark)." The system is embodied mostly in compact, lightweight, portable units (see figure) denoted video time-code units (VTUs) - one VTU for each video camera. The system is scalable in that any number of camera recordings can be synchronized. The estimated retail price per unit would be about $350 (in 2006 dollars). The need for this or another synchronization system external to video cameras arises because most video cameras do not include internal means for maintaining synchronization with other video cameras. Unlike prior video-camera-synchronization systems, this system does not depend on continuous cable or radio links between cameras (however, it does depend on occasional cable links lasting a few seconds). Also, whereas the time codes used in prior video-camera-synchronization systems typically repeat after 24 hours, the time code used in this system does not repeat for slightly more than 136 years; hence, this system is much better suited for long-term deployment of multiple cameras.

A Distributed Platform for Global-Scale Agent-Based Models of Disease Transmission

PubMed Central

Parker, Jon; Epstein, Joshua M.

2013-01-01

The Global-Scale Agent Model (GSAM) is presented. The GSAM is a high-performance distributed platform for agent-based epidemic modeling capable of simulating a disease outbreak in a population of several billion agents. It is unprecedented in its scale, its speed, and its use of Java. Solutions to multiple challenges inherent in distributing massive agent-based models are presented. Communication, synchronization, and memory usage are among the topics covered in detail. The memory usage discussion is Java specific. However, the communication and synchronization discussions apply broadly. We provide benchmarks illustrating the GSAM’s speed and scalability. PMID:24465120

Combatant eye protection: an introduction to the blue light hazard

NASA Astrophysics Data System (ADS)

Lattimore, Morris R.

2016-05-01

Emerging evidence of metabolic vulnerability to visible blue light is vitally important, as it is indicative of a scalable threshold effect. Added stressors (e.g., increased altitude or contact lens wear) could shift the wavelength effects toward a more damaging clinical picture. Recent reports have indicated rod photo-pigment damage resulting from solar blue-light exposures, adversely affecting unaided night vision, a militarily important performance decrement. The activation wavelength for the daily synchronous setting of the Circadian Clock, which regulates the synchronization of all hormonal and organ systems throughout the body, falls within this blue light perceptual range.

Numerical Simulations of Reacting Flows Using Asynchrony-Tolerant Schemes for Exascale Computing

NASA Astrophysics Data System (ADS)

Cleary, Emmet; Konduri, Aditya; Chen, Jacqueline

2017-11-01

Communication and data synchronization between processing elements (PEs) are likely to pose a major challenge in scalability of solvers at the exascale. Recently developed asynchrony-tolerant (AT) finite difference schemes address this issue by relaxing communication and synchronization between PEs at a mathematical level while preserving accuracy, resulting in improved scalability. The performance of these schemes has been validated for simple linear and nonlinear homogeneous PDEs. However, many problems of practical interest are governed by highly nonlinear PDEs with source terms, whose solution may be sensitive to perturbations caused by communication asynchrony. The current work applies the AT schemes to combustion problems with chemical source terms, yielding a stiff system of PDEs with nonlinear source terms highly sensitive to temperature. Examples shown will use single-step and multi-step CH4 mechanisms for 1D premixed and nonpremixed flames. Error analysis will be discussed both in physical and spectral space. Results show that additional errors introduced by the AT schemes are negligible and the schemes preserve their accuracy. We acknowledge funding from the DOE Computational Science Graduate Fellowship administered by the Krell Institute.

A Byzantine-Fault Tolerant Self-Stabilizing Protocol for Distributed Clock Synchronization Systems

NASA Technical Reports Server (NTRS)

Malekpour, Mahyar R.

2006-01-01

Embedded distributed systems have become an integral part of safety-critical computing applications, necessitating system designs that incorporate fault tolerant clock synchronization in order to achieve ultra-reliable assurance levels. Many efficient clock synchronization protocols do not, however, address Byzantine failures, and most protocols that do tolerate Byzantine failures do not self-stabilize. Of the Byzantine self-stabilizing clock synchronization algorithms that exist in the literature, they are based on either unjustifiably strong assumptions about initial synchrony of the nodes or on the existence of a common pulse at the nodes. The Byzantine self-stabilizing clock synchronization protocol presented here does not rely on any assumptions about the initial state of the clocks. Furthermore, there is neither a central clock nor an externally generated pulse system. The proposed protocol converges deterministically, is scalable, and self-stabilizes in a short amount of time. The convergence time is linear with respect to the self-stabilization period. Proofs of the correctness of the protocol as well as the results of formal verification efforts are reported.

Scalable polylithic on-package integratable apparatus and method

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

Khare, Surhud; Somasekhar, Dinesh; Borkar, Shekhar Y.

Described is an apparatus which comprises: a first die including: a processing core; a crossbar switch coupled to the processing core; and a first edge interface coupled to the crossbar switch; and a second die including: a first edge interface positioned at a periphery of the second die and coupled to the first edge interface of the first die, wherein the first edge interface of the first die and the first edge interface of the second die are positioned across each other; a clock synchronization circuit coupled to the second edge interface; and a memory interface coupled to the clockmore » synchronization circuit.« less

Novel Bioreactor Platform for Scalable Cardiomyogenic Differentiation from Pluripotent Stem Cell-Derived Embryoid Bodies.

PubMed

Rungarunlert, Sasitorn; Ferreira, Joao N; Dinnyes, Andras

2016-01-01

Generation of cardiomyocytes from pluripotent stem cells (PSCs) is a common and valuable approach to produce large amount of cells for various applications, including assays and models for drug development, cell-based therapies, and tissue engineering. All these applications would benefit from a reliable bioreactor-based methodology to consistently generate homogenous PSC-derived embryoid bodies (EBs) at a large scale, which can further undergo cardiomyogenic differentiation. The goal of this chapter is to describe a scalable method to consistently generate large amount of homogeneous and synchronized EBs from PSCs. This method utilizes a slow-turning lateral vessel bioreactor to direct the EB formation and their subsequent cardiomyogenic lineage differentiation.

: A Scalable and Transparent System for Simulating MPI Programs

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

Perumalla, Kalyan S

2010-01-01

is a scalable, transparent system for experimenting with the execution of parallel programs on simulated computing platforms. The level of simulated detail can be varied for application behavior as well as for machine characteristics. Unique features of are repeatability of execution, scalability to millions of simulated (virtual) MPI ranks, scalability to hundreds of thousands of host (real) MPI ranks, portability of the system to a variety of host supercomputing platforms, and the ability to experiment with scientific applications whose source-code is available. The set of source-code interfaces supported by is being expanded to support a wider set of applications, andmore » MPI-based scientific computing benchmarks are being ported. In proof-of-concept experiments, has been successfully exercised to spawn and sustain very large-scale executions of an MPI test program given in source code form. Low slowdowns are observed, due to its use of purely discrete event style of execution, and due to the scalability and efficiency of the underlying parallel discrete event simulation engine, sik. In the largest runs, has been executed on up to 216,000 cores of a Cray XT5 supercomputer, successfully simulating over 27 million virtual MPI ranks, each virtual rank containing its own thread context, and all ranks fully synchronized by virtual time.« less

Scalable Energy Networks to Promote Energy Security

DTIC Science & Technology

2011-07-01

commodity. Consider current challenges of converting energy and synchronizing sources with loads—for example, capturing solar energy to provide hot water...distributed micro-generation1 (for example, roof-mounted solar panels) and plug-in elec- tric/hybrid vehicles. The imperative extends to our national...transformers, battery chargers ■■ distribution: pumps, pipes, switches, cables ■■ applications: lighting, automobiles, personal electronic devices

Using Synchronous Technology to Enrich Student Learning

ERIC Educational Resources Information Center

Wang, Charles Xiaoxue; Jaeger, David; Liu, Jinxia; Guo, Xiaoning; Xie, Nan

2013-01-01

To explore the potential applications of synchronous technology to enrich student learning, faculty members from an American regional state university and a Chinese regional university collaborated to find appropriate ways to integrate synchronous technology (e.g., Adobe Connect) into an educational technology program in the American university…

An Empirical Investigation of Student Acceptance of Synchronous E-Learning in an Online University

ERIC Educational Resources Information Center

Kang, Minseok; Shin, Won sug

2015-01-01

This study proposes an extended technology acceptance model to predict acceptance of synchronous e-learning by examining relationships among variables associated with factors influencing the technology acceptance of synchronous e-learning. Learners at an online university participated through an online survey; there were 251 respondents in all.…

Self organization of wireless sensor networks using ultra-wideband radios

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

Dowla, Farid U; Nekoogar, Franak; Spiridon, Alex

A novel UWB communications method and system that provides self-organization for wireless sensor networks is introduced. The self-organization is in terms of scalability, power conservation, channel estimation, and node synchronization in wireless sensor networks. The UWB receiver in the present invention adds two new tasks to conventional TR receivers. The two additional units are SNR enhancing unit and timing acquisition and tracking unit.

Key Considerations of Community, Scalability, Supportability, Security, and Functionality in Selecting Open-Source Software in California Universities as Perceived by Technology Leaders

ERIC Educational Resources Information Center

Britton, Todd Alan

2014-01-01

Purpose: The purpose of this study was to examine the key considerations of community, scalability, supportability, security, and functionality for selecting open-source software in California universities as perceived by technology leaders. Methods: After a review of the cogent literature, the key conceptual framework categories were identified…

A Synchronous Distance Education Course for Non-Scientists Coordinated among Three Universities

ERIC Educational Resources Information Center

Smith, Tamara Floyd; Baah, David; Bradley, James; Sidler, Michelle; Hall, Rosine; Daughtrey, Terrell; Curtis, Christine

2010-01-01

A Synchronous Distance Education (SDE) course, jointly offered by Auburn University, Tuskegee University and Auburn University at Montgomery, introduced non-science majors to the concepts of nanoscience. Lectures originated from each of the three campuses during the semester, and video conferencing equipment allowed students at all three campuses…

Characteristic Evaluation of Synchronous Motors Using an Universal Drive System with a Real-Time Interface

NASA Astrophysics Data System (ADS)

Amano, Yoko; Ogasawara, Satoshi

In this paper, a new universal drive system of synchronous motors used Real-Time Interface (RTI) performs characteristic evaluation of Synchronous Reluctance (SynR) motors and Surface Permanent Magnet (SPM) synchronous motors. The RTI connects directly a simulation model with experimental equipment, and makes it possible to use the simulation model for an experiment. The RTI is very effective in the early detection of an actual problem and examination of solution technique. Moreover, it concentrates on examination of control algorithm, and efficient research and development are enabled. A measuring system of synchronous motors is built by the universal drive system. The examination of various synchronous motors is possible for the measurement system using the same control algorithm. Characteristic evaluation of a SynR motor and a SPM synchronous motor that are the same gap length and stator was performed using the measuring system. The measurement result shows experimentally that motor loss of the SynR motor is smaller rather than the SPM synchronous motor, at the time of high speed and low load operation. For example, the SynR motor is suitable to hybrid cars with the comparatively long time of low load and high-speed operation.

Support of Multidimensional Parallelism in the OpenMP Programming Model

NASA Technical Reports Server (NTRS)

Jin, Hao-Qiang; Jost, Gabriele

2003-01-01

OpenMP is the current standard for shared-memory programming. While providing ease of parallel programming, the OpenMP programming model also has limitations which often effect the scalability of applications. Examples for these limitations are work distribution and point-to-point synchronization among threads. We propose extensions to the OpenMP programming model which allow the user to easily distribute the work in multiple dimensions and synchronize the workflow among the threads. The proposed extensions include four new constructs and the associated runtime library. They do not require changes to the source code and can be implemented based on the existing OpenMP standard. We illustrate the concept in a prototype translator and test with benchmark codes and a cloud modeling code.

Simulation of Physical and Media Access Control (MAC) for Resilient and Scalable Wireless Sensor Networks

DTIC Science & Technology

2006-03-01

schedules uniform wakeup for all the nodes. When data is transmitted, only specific destination nodes need to remain awake. Other nodes not participating...of Carrier Sense ....................................................................30 3. Synchronous vs Asynchronous Wakeup Mechanisms...proposal is to have each pair of node schedule their “wake-up” or “beacons” independent of the IEEE 802.11 PSM beacon. In the ideal scenario, where

Ising universality describes emergent long-range synchronization of coupled ecological oscillators

NASA Astrophysics Data System (ADS)

Noble, Andrew

Understanding the synchronization of oscillations across space is fundamentally important to many scientific disciplines. In ecology, long-range synchronization of oscillations in spatial populations may elevate extinction risk and signal an impending catastrophe. The prevailing assumption is that synchronization on distances longer than the dispersal scale can only be due to environmental correlation. By contrast, recent work shows how scale-invariant synchronization can emerge from locally coupled population dynamics. In particular, we have found that the transition from incoherence to long-range synchronization of coupled ecological two-cycles is described by the Ising universality class. I will discuss evidence that an Ising critical point describes long-range correlations found in data on the individual yields of female pistachio trees in a large orchard. NSF INSPIRE Grant No. 1344187.

Distributed-Memory Breadth-First Search on Massive Graphs

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

Buluc, Aydin; Beamer, Scott; Madduri, Kamesh

This chapter studies the problem of traversing large graphs using the breadth-first search order on distributed-memory supercomputers. We consider both the traditional level-synchronous top-down algorithm as well as the recently discovered direction optimizing algorithm. We analyze the performance and scalability trade-offs in using different local data structures such as CSR and DCSC, enabling in-node multithreading, and graph decompositions such as 1D and 2D decomposition.

Power-Scalable Blue-Green Bessel Beams

DTIC Science & Technology

2016-02-23

19b. TELEPHONE NUMBER (Include area code) 02/23/2016 Final Technical JAN 2011 - DEC 2013 Power-Scalable Blue -Green Bessel Beams Siddharth Ramachandran...fiber lasers, non-traditional emission wavelengths, high-power blue -green tunabel lasers U U U SAR 11 Siddharth Ramachandran 617-353-9811 1 Power...Scalable Blue -Green Bessel Beams Siddharth Ramachandran Photonics Center, Boston University, 8 Saint Mary’s Street, Boston, MA 02215 phone: (617) 353

Final Report. Center for Scalable Application Development Software

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

Mellor-Crummey, John

2014-10-26

The Center for Scalable Application Development Software (CScADS) was established as a part- nership between Rice University, Argonne National Laboratory, University of California Berkeley, University of Tennessee – Knoxville, and University of Wisconsin – Madison. CScADS pursued an integrated set of activities with the aim of increasing the productivity of DOE computational scientists by catalyzing the development of systems software, libraries, compilers, and tools for leadership computing platforms. Principal Center activities were workshops to engage the research community in the challenges of leadership computing, research and development of open-source software, and work with computational scientists to help them develop codesmore » for leadership computing platforms. This final report summarizes CScADS activities at Rice University in these areas.« less

Emergent long-range synchronization of oscillating ecological populations without external forcing described by Ising universality

PubMed Central

Noble, Andrew E.; Machta, Jonathan; Hastings, Alan

2015-01-01

Understanding the synchronization of oscillations across space is fundamentally important to many scientific disciplines. In ecology, long-range synchronization of oscillations in spatial populations may elevate extinction risk and signal an impending catastrophe. The prevailing assumption is that synchronization on distances longer than the dispersal scale can only be due to environmental correlation (the Moran effect). In contrast, we show how long-range synchronization can emerge over distances much longer than the length scales of either dispersal or environmental correlation. In particular, we demonstrate that the transition from incoherence to long-range synchronization of two-cycle oscillations in noisy spatial population models is described by the Ising universality class of statistical physics. This result shows, in contrast to all previous work, how the Ising critical transition can emerge directly from the dynamics of ecological populations. PMID:25851364

Time Synchronization in Wireless Sensor Networks

DTIC Science & Technology

2003-01-01

University of California Los Angeles Time Synchronization in Wireless Sensor Networks A dissertation submitted in partial satisfaction of the...4. TITLE AND SUBTITLE Time Synchronization in Wireless Sensor Networks 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...1 1.1 Wireless Sensor Networks . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Time Synchronization in Sensor Networks

Optically Driven Spin Based Quantum Dots for Quantum Computing - Research Area 6 Physics 6.3.2

DTIC Science & Technology

2015-12-15

quantum dots (SAQD) in Schottky diodes . Based on spins in these dots, a scalable architecture has been proposed [Adv. in Physics, 59, 703 (2010)] by us...housed in two coupled quantum dots with tunneling between them, as described above, may not be scalable but can serve as a node in a quantum network. The... tunneling -coupled two-electron spin ground states in the vertically coupled quantum dots for “universal computation” two spin qubits within the universe of

Measures of Quantum Synchronization in Continuous Variable Systems

NASA Astrophysics Data System (ADS)

Mari, A.; Farace, A.; Didier, N.; Giovannetti, V.; Fazio, R.

2013-09-01

We introduce and characterize two different measures which quantify the level of synchronization of coupled continuous variable quantum systems. The two measures allow us to extend to the quantum domain the notions of complete and phase synchronization. The Heisenberg principle sets a universal bound to complete synchronization. The measure of phase synchronization is, in principle, unbounded; however, in the absence of quantum resources (e.g., squeezing) the synchronization level is bounded below a certain threshold. We elucidate some interesting connections between entanglement and synchronization and, finally, discuss an application based on quantum optomechanical systems.

Measures of quantum synchronization in continuous variable systems.

PubMed

Mari, A; Farace, A; Didier, N; Giovannetti, V; Fazio, R

2013-09-06

We introduce and characterize two different measures which quantify the level of synchronization of coupled continuous variable quantum systems. The two measures allow us to extend to the quantum domain the notions of complete and phase synchronization. The Heisenberg principle sets a universal bound to complete synchronization. The measure of phase synchronization is, in principle, unbounded; however, in the absence of quantum resources (e.g., squeezing) the synchronization level is bounded below a certain threshold. We elucidate some interesting connections between entanglement and synchronization and, finally, discuss an application based on quantum optomechanical systems.

High-order asynchrony-tolerant finite difference schemes for partial differential equations

NASA Astrophysics Data System (ADS)

Aditya, Konduri; Donzis, Diego A.

2017-12-01

Synchronizations of processing elements (PEs) in massively parallel simulations, which arise due to communication or load imbalances between PEs, significantly affect the scalability of scientific applications. We have recently proposed a method based on finite-difference schemes to solve partial differential equations in an asynchronous fashion - synchronization between PEs is relaxed at a mathematical level. While standard schemes can maintain their stability in the presence of asynchrony, their accuracy is drastically affected. In this work, we present a general methodology to derive asynchrony-tolerant (AT) finite difference schemes of arbitrary order of accuracy, which can maintain their accuracy when synchronizations are relaxed. We show that there are several choices available in selecting a stencil to derive these schemes and discuss their effect on numerical and computational performance. We provide a simple classification of schemes based on the stencil and derive schemes that are representative of different classes. Their numerical error is rigorously analyzed within a statistical framework to obtain the overall accuracy of the solution. Results from numerical experiments are used to validate the performance of the schemes.

Information Security Analysis Using Game Theory and Simulation

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

Schlicher, Bob G; Abercrombie, Robert K

Information security analysis can be performed using game theory implemented in dynamic simulations of Agent Based Models (ABMs). Such simulations can be verified with the results from game theory analysis and further used to explore larger scale, real world scenarios involving multiple attackers, defenders, and information assets. Our approach addresses imperfect information and scalability that allows us to also address previous limitations of current stochastic game models. Such models only consider perfect information assuming that the defender is always able to detect attacks; assuming that the state transition probabilities are fixed before the game assuming that the players actions aremore » always synchronous; and that most models are not scalable with the size and complexity of systems under consideration. Our use of ABMs yields results of selected experiments that demonstrate our proposed approach and provides a quantitative measure for realistic information systems and their related security scenarios.« less

ID201202961, DOE S-124,539, Information Security Analysis Using Game Theory and Simulation

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

Abercrombie, Robert K; Schlicher, Bob G

Information security analysis can be performed using game theory implemented in dynamic simulations of Agent Based Models (ABMs). Such simulations can be verified with the results from game theory analysis and further used to explore larger scale, real world scenarios involving multiple attackers, defenders, and information assets. Our approach addresses imperfect information and scalability that allows us to also address previous limitations of current stochastic game models. Such models only consider perfect information assuming that the defender is always able to detect attacks; assuming that the state transition probabilities are fixed before the game assuming that the players actions aremore » always synchronous; and that most models are not scalable with the size and complexity of systems under consideration. Our use of ABMs yields results of selected experiments that demonstrate our proposed approach and provides a quantitative measure for realistic information systems and their related security scenarios.« less

Networking and AI systems: Requirements and benefits

NASA Technical Reports Server (NTRS)

1988-01-01

The price performance benefits of network systems is well documented. The ability to share expensive resources sold timesharing for mainframes, department clusters of minicomputers, and now local area networks of workstations and servers. In the process, other fundamental system requirements emerged. These have now been generalized with open system requirements for hardware, software, applications and tools. The ability to interconnect a variety of vendor products has led to a specification of interfaces that allow new techniques to extend existing systems for new and exciting applications. As an example of the message passing system, local area networks provide a testbed for many of the issues addressed by future concurrent architectures: synchronization, load balancing, fault tolerance and scalability. Gold Hill has been working with a number of vendors on distributed architectures that range from a network of workstations to a hypercube of microprocessors with distributed memory. Results from early applications are promising both for performance and scalability.

Intercultural Competence in Synchronous Communication between Native and Non-Native Speakers of Spanish

ERIC Educational Resources Information Center

Fernández, Susana S.; Pozzo, María Isabel

2017-01-01

This paper discusses to what extent synchronous communication via Skype by Argentine university students of History and Danish university students of Spanish contributed to fostering intercultural competence in the two groups of participants. Intercultural gains are considered both as part of the planned tasks to be solved by the participants…

An Investigation of the Use of Synchronous Text-Based Communication Technologies by Undergraduate University Students

ERIC Educational Resources Information Center

Austin, Richard John

2012-01-01

This dissertation presents the results of an exploratory study which examined the use of synchronous text-based communication technologies (SMS texting and instant messaging) by undergraduate university students generally 18 to 24 years old. Preliminary focus groups were conducted in order to gain additional understanding of their usage of these…

Synchronous and Asynchronous E-Language Learning: A Case Study of Virtual University of Pakistan

ERIC Educational Resources Information Center

Perveen, Ayesha

2016-01-01

This case study evaluated the impact of synchronous and asynchronous E-Language Learning activities (ELL-ivities) in an E-Language Learning Environment (ELLE) at Virtual University of Pakistan. The purpose of the study was to assess e-language learning analytics based on the constructivist approach of collaborative construction of knowledge. The…

Designing and application of SAN extension interface based on CWDM

NASA Astrophysics Data System (ADS)

Qin, Leihua; Yu, Shengsheng; Zhou, Jingli

2005-11-01

As Fibre Channel (FC) becomes the protocol of choice within corporate data centers, enterprises are increasingly deploying SANs in their data central. In order to mitigate the risk of losing data and improve the availability of data, more and more enterprises are increasingly adopting storage extension technologies to replicate their business critical data to a secondary site. Transmitting this information over distance requires a carrier grade environment with zero data loss, scalable throughput, low jitter, high security and ability to travel long distance. To address this business requirements, there are three basic architectures for storage extension, they are Storage over Internet Protocol, Storage over Synchronous Optical Network/Synchronous Digital Hierarchy (SONET/SDH) and Storage over Dense Wavelength Division Multiplexing (DWDM). Each approach varies in functionality, complexity, cost, scalability, security, availability , predictable behavior (bandwidth, jitter, latency) and multiple carrier limitations. Compared with these connectiviy technologies,Coarse Wavelength Division Multiplexing (CWDM) is a Simplified, Low Cost and High Performance connectivity solutions for enterprises to deploy their storage extension. In this paper, we design a storage extension connectivity over CWDM and test it's electrical characteristic and random read and write performance of disk array through the CWDM connectivity, testing result show us that the performance of the connectivity over CWDM is acceptable. Furthermore, we propose three kinds of network architecture of SAN extension based on CWDM interface. Finally the credit-Based flow control mechanism of FC, and the relationship between credits and extension distance is analyzed.

Social and Virtual Networks: Evaluating Synchronous Online Interviewing Using Instant Messenger

ERIC Educational Resources Information Center

Hinchcliffe, Vanessa; Gavin, Helen

2009-01-01

This paper describes an evaluation of the quality and utility of synchronous online interviewing for data collection in social network research. Synchronous online interviews facilitated by Instant Messenger as the communication medium, were undertaken with ten final year university students. Quantitative and qualitative content analysis of…

Sensor Network Localization by Eigenvector Synchronization Over the Euclidean Group

PubMed Central

CUCURINGU, MIHAI; LIPMAN, YARON; SINGER, AMIT

2013-01-01

We present a new approach to localization of sensors from noisy measurements of a subset of their Euclidean distances. Our algorithm starts by finding, embedding, and aligning uniquely realizable subsets of neighboring sensors called patches. In the noise-free case, each patch agrees with its global positioning up to an unknown rigid motion of translation, rotation, and possibly reflection. The reflections and rotations are estimated using the recently developed eigenvector synchronization algorithm, while the translations are estimated by solving an overdetermined linear system. The algorithm is scalable as the number of nodes increases and can be implemented in a distributed fashion. Extensive numerical experiments show that it compares favorably to other existing algorithms in terms of robustness to noise, sparse connectivity, and running time. While our approach is applicable to higher dimensions, in the current article, we focus on the two-dimensional case. PMID:23946700

A scalable healthcare information system based on a service-oriented architecture.

PubMed

Yang, Tzu-Hsiang; Sun, Yeali S; Lai, Feipei

2011-06-01

Many existing healthcare information systems are composed of a number of heterogeneous systems and face the important issue of system scalability. This paper first describes the comprehensive healthcare information systems used in National Taiwan University Hospital (NTUH) and then presents a service-oriented architecture (SOA)-based healthcare information system (HIS) based on the service standard HL7. The proposed architecture focuses on system scalability, in terms of both hardware and software. Moreover, we describe how scalability is implemented in rightsizing, service groups, databases, and hardware scalability. Although SOA-based systems sometimes display poor performance, through a performance evaluation of our HIS based on SOA, the average response time for outpatient, inpatient, and emergency HL7Central systems are 0.035, 0.04, and 0.036 s, respectively. The outpatient, inpatient, and emergency WebUI average response times are 0.79, 1.25, and 0.82 s. The scalability of the rightsizing project and our evaluation results show that the SOA HIS we propose provides evidence that SOA can provide system scalability and sustainability in a highly demanding healthcare information system.

iPads in Medical Language Courses at the University of Helsinki

ERIC Educational Resources Information Center

Wallinheimo, Kirsi; Pitkänen, Kari K.

2016-01-01

In recent years, the Faculty of Medicine at the University of Helsinki has systematically developed and synchronized its teaching technology, and new iPad-based tools have been an important part of this development. The aim has been to provide the students and teachers in the faculty with synchronized tools that can be used as a basis of a shared…

Joint source-channel coding for motion-compensated DCT-based SNR scalable video.

PubMed

Kondi, Lisimachos P; Ishtiaq, Faisal; Katsaggelos, Aggelos K

2002-01-01

In this paper, we develop an approach toward joint source-channel coding for motion-compensated DCT-based scalable video coding and transmission. A framework for the optimal selection of the source and channel coding rates over all scalable layers is presented such that the overall distortion is minimized. The algorithm utilizes universal rate distortion characteristics which are obtained experimentally and show the sensitivity of the source encoder and decoder to channel errors. The proposed algorithm allocates the available bit rate between scalable layers and, within each layer, between source and channel coding. We present the results of this rate allocation algorithm for video transmission over a wireless channel using the H.263 Version 2 signal-to-noise ratio (SNR) scalable codec for source coding and rate-compatible punctured convolutional (RCPC) codes for channel coding. We discuss the performance of the algorithm with respect to the channel conditions, coding methodologies, layer rates, and number of layers.

Quantum synchronization of a driven self-sustained oscillator.

PubMed

Walter, Stefan; Nunnenkamp, Andreas; Bruder, Christoph

2014-03-07

Synchronization is a universal phenomenon that is important both in fundamental studies and in technical applications. Here we investigate synchronization in the simplest quantum-mechanical scenario possible, i.e., a quantum-mechanical self-sustained oscillator coupled to an external harmonic drive. Using the power spectrum we analyze synchronization in terms of frequency entrainment and frequency locking in close analogy to the classical case. We show that there is a steplike crossover to a synchronized state as a function of the driving strength. In contrast to the classical case, there is a finite threshold value in driving. Quantum noise reduces the synchronized region and leads to a deviation from strict frequency locking.

Synchronicity and the meaning-making psyche.

PubMed

Colman, Warren

2011-09-01

This paper contrasts Jung's account of synchronicity as evidence of an objective principle of meaning in Nature with a view that emphasizes human meaning-making. All synchronicities generate indicative signs but only where this becomes a 'living symbol' of a transcendent intentionality at work in a living universe does synchronicity generate the kind of symbolic meaning that led Jung to posit the existence of a Universal Mind. This is regarded as a form of personal, experiential knowledge belonging to the 'imaginal world of meaning' characteristic of the 'primordial mind', as opposed to the 'rational world of knowledge' in which Jung attempted to present his experiences as if they were empirically and publicly verifiable. Whereas rational knowledge depends on a form of meaning in which causal chains and logical links are paramount, imaginal meaning is generated by forms of congruent correspondence-a feature that synchronicity shares with metaphor and symbol-and the creation of narratives by means of retroactive organization of its constituent elements. © 2011, The Society of Analytical Psychology.

Extreme Performance Scalable Operating Systems Final Progress Report (July 1, 2008 - October 31, 2011)

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

Malony, Allen D; Shende, Sameer

This is the final progress report for the FastOS (Phase 2) (FastOS-2) project with Argonne National Laboratory and the University of Oregon (UO). The project started at UO on July 1, 2008 and ran until April 30, 2010, at which time a six-month no-cost extension began. The FastOS-2 work at UO delivered excellent results in all research work areas: * scalable parallel monitoring * kernel-level performance measurement * parallel I/0 system measurement * large-scale and hybrid application performance measurement * onlne scalable performance data reduction and analysis * binary instrumentation

Winning One Program at a Time: A Systemic Approach

ERIC Educational Resources Information Center

Schultz, Adam; Zimmerman, Kay

2016-01-01

Many Universities are missing an opportunity to focus student recruitment marketing efforts and budget at the program level, which can offer lower priced advertising opportunities with higher conversion rates than traditional University level marketing initiatives. At NC State University, we have begun to deploy a scalable, low-cost, program level…

A peripheral component interconnect express-based scalable and highly integrated pulsed spectrometer for solution state dynamic nuclear polarization.

PubMed

He, Yugui; Feng, Jiwen; Zhang, Zhi; Wang, Chao; Wang, Dong; Chen, Fang; Liu, Maili; Liu, Chaoyang

2015-08-01

High sensitivity, high data rates, fast pulses, and accurate synchronization all represent challenges for modern nuclear magnetic resonance spectrometers, which make any expansion or adaptation of these devices to new techniques and experiments difficult. Here, we present a Peripheral Component Interconnect Express (PCIe)-based highly integrated distributed digital architecture pulsed spectrometer that is implemented with electron and nucleus double resonances and is scalable specifically for broad dynamic nuclear polarization (DNP) enhancement applications, including DNP-magnetic resonance spectroscopy/imaging (DNP-MRS/MRI). The distributed modularized architecture can implement more transceiver channels flexibly to meet a variety of MRS/MRI instrumentation needs. The proposed PCIe bus with high data rates can significantly improve data transmission efficiency and communication reliability and allow precise control of pulse sequences. An external high speed double data rate memory chip is used to store acquired data and pulse sequence elements, which greatly accelerates the execution of the pulse sequence, reduces the TR (time of repetition) interval, and improves the accuracy of TR in imaging sequences. Using clock phase-shift technology, we can produce digital pulses accurately with high timing resolution of 1 ns and narrow widths of 4 ns to control the microwave pulses required by pulsed DNP and ensure overall system synchronization. The proposed spectrometer is proved to be both feasible and reliable by observation of a maximum signal enhancement factor of approximately -170 for (1)H, and a high quality water image was successfully obtained by DNP-enhanced spin-echo (1)H MRI at 0.35 T.

A peripheral component interconnect express-based scalable and highly integrated pulsed spectrometer for solution state dynamic nuclear polarization

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

He, Yugui; Liu, Chaoyang, E-mail: chyliu@wipm.ac.cn; State Key Laboratory of Magnet Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071

2015-08-15

High sensitivity, high data rates, fast pulses, and accurate synchronization all represent challenges for modern nuclear magnetic resonance spectrometers, which make any expansion or adaptation of these devices to new techniques and experiments difficult. Here, we present a Peripheral Component Interconnect Express (PCIe)-based highly integrated distributed digital architecture pulsed spectrometer that is implemented with electron and nucleus double resonances and is scalable specifically for broad dynamic nuclear polarization (DNP) enhancement applications, including DNP-magnetic resonance spectroscopy/imaging (DNP-MRS/MRI). The distributed modularized architecture can implement more transceiver channels flexibly to meet a variety of MRS/MRI instrumentation needs. The proposed PCIe bus with highmore » data rates can significantly improve data transmission efficiency and communication reliability and allow precise control of pulse sequences. An external high speed double data rate memory chip is used to store acquired data and pulse sequence elements, which greatly accelerates the execution of the pulse sequence, reduces the TR (time of repetition) interval, and improves the accuracy of TR in imaging sequences. Using clock phase-shift technology, we can produce digital pulses accurately with high timing resolution of 1 ns and narrow widths of 4 ns to control the microwave pulses required by pulsed DNP and ensure overall system synchronization. The proposed spectrometer is proved to be both feasible and reliable by observation of a maximum signal enhancement factor of approximately −170 for {sup 1}H, and a high quality water image was successfully obtained by DNP-enhanced spin-echo {sup 1}H MRI at 0.35 T.« less

Multiband Radio Frequency Interconnect (MRFI) Technology For Next Generation Mobile/Airborne Computing Systems

DTIC Science & Technology

2017-02-01

enable high scalability and reconfigurability for inter-CPU/Memory communications with an increased number of communication channels in frequency ...interconnect technology (MRFI) to enable high scalability and re-configurability for inter-CPU/Memory communications with an increased number of communication ...testing in the University of California, Los Angeles (UCLA) Center for High Frequency Electronics, and Dr. Afshin Momtaz at Broadcom Corporation for

Scalable Anonymous Group Communication in the Anytrust Model

DTIC Science & Technology

2012-04-10

Scalable Anonymous Group Communication in the Anytrust Model David Isaac Wolinsky, Henry Corrigan-Gibbs, and Bryan Ford Yale University...12th KDD, Aug. 2006. [10] D. Chaum . Untraceable electronic mail, return addresses, and digital pseudonyms. Communications of the ACM, 24(2), Feb...1981. [11] D. Chaum . The dining cryptographers problem: Unconditional sender and recipient untraceability. Journal of Cryptology, 1(1):65–75, Jan. 1988

Digital quantum simulators in a scalable architecture of hybrid spin-photon qubits

PubMed Central

Chiesa, Alessandro; Santini, Paolo; Gerace, Dario; Raftery, James; Houck, Andrew A.; Carretta, Stefano

2015-01-01

Resolving quantum many-body problems represents one of the greatest challenges in physics and physical chemistry, due to the prohibitively large computational resources that would be required by using classical computers. A solution has been foreseen by directly simulating the time evolution through sequences of quantum gates applied to arrays of qubits, i.e. by implementing a digital quantum simulator. Superconducting circuits and resonators are emerging as an extremely promising platform for quantum computation architectures, but a digital quantum simulator proposal that is straightforwardly scalable, universal, and realizable with state-of-the-art technology is presently lacking. Here we propose a viable scheme to implement a universal quantum simulator with hybrid spin-photon qubits in an array of superconducting resonators, which is intrinsically scalable and allows for local control. As representative examples we consider the transverse-field Ising model, a spin-1 Hamiltonian, and the two-dimensional Hubbard model and we numerically simulate the scheme by including the main sources of decoherence. PMID:26563516

Scalable Generation of Universal Platelets from Human Induced Pluripotent Stem Cells

PubMed Central

Feng, Qiang; Shabrani, Namrata; Thon, Jonathan N.; Huo, Hongguang; Thiel, Austin; Machlus, Kellie R.; Kim, Kyungho; Brooks, Julie; Li, Feng; Luo, Chenmei; Kimbrel, Erin A.; Wang, Jiwu; Kim, Kwang-Soo; Italiano, Joseph; Cho, Jaehyung; Lu, Shi-Jiang; Lanza, Robert

2014-01-01

Summary Human induced pluripotent stem cells (iPSCs) provide a potentially replenishable source for the production of transfusable platelets. Here, we describe a method to generate megakaryocytes (MKs) and functional platelets from iPSCs in a scalable manner under serum/feeder-free conditions. The method also permits the cryopreservation of MK progenitors, enabling a rapid “surge” capacity when large numbers of platelets are needed. Ultrastructural/morphological analyses show no major differences between iPSC platelets and human blood platelets. iPSC platelets form aggregates, lamellipodia, and filopodia after activation and circulate in macrophage-depleted animals and incorporate into developing mouse thrombi in a manner identical to human platelets. By knocking out the β2-microglobulin gene, we have generated platelets that are negative for the major histocompatibility antigens. The scalable generation of HLA-ABC-negative platelets from a renewable cell source represents an important step toward generating universal platelets for transfusion as well as a potential strategy for the management of platelet refractoriness. PMID:25418726

Scalable generation of universal platelets from human induced pluripotent stem cells.

PubMed

Feng, Qiang; Shabrani, Namrata; Thon, Jonathan N; Huo, Hongguang; Thiel, Austin; Machlus, Kellie R; Kim, Kyungho; Brooks, Julie; Li, Feng; Luo, Chenmei; Kimbrel, Erin A; Wang, Jiwu; Kim, Kwang-Soo; Italiano, Joseph; Cho, Jaehyung; Lu, Shi-Jiang; Lanza, Robert

2014-11-11

Human induced pluripotent stem cells (iPSCs) provide a potentially replenishable source for the production of transfusable platelets. Here, we describe a method to generate megakaryocytes (MKs) and functional platelets from iPSCs in a scalable manner under serum/feeder-free conditions. The method also permits the cryopreservation of MK progenitors, enabling a rapid "surge" capacity when large numbers of platelets are needed. Ultrastructural/morphological analyses show no major differences between iPSC platelets and human blood platelets. iPSC platelets form aggregates, lamellipodia, and filopodia after activation and circulate in macrophage-depleted animals and incorporate into developing mouse thrombi in a manner identical to human platelets. By knocking out the β2-microglobulin gene, we have generated platelets that are negative for the major histocompatibility antigens. The scalable generation of HLA-ABC-negative platelets from a renewable cell source represents an important step toward generating universal platelets for transfusion as well as a potential strategy for the management of platelet refractoriness.

Stop the supply chain insanity. Retail as a model for hospitals.

PubMed

Belkoski, David A

2008-04-01

The healthcare supply chain has yet to embrace any single industrywide source for synchronized product data. A synchronized product data system is a keystone in other multibillion-dollar markets. University Health Care System (UHCS), Augusta, Ga., developed a pilot program that demonstrates the benefits of data standardization and synchronization and enabled the system to recognize productivity gains in the supply chain.

Shadow-Bitcoin: Scalable Simulation via Direct Execution of Multi-Threaded Applications

DTIC Science & Technology

2015-08-10

Shadow- Bitcoin : Scalable Simulation via Direct Execution of Multi-threaded Applications Andrew Miller University of Maryland amiller@cs.umd.edu Rob...Shadow plug-in that directly executes the Bitcoin reference client software. To demonstrate the usefulness of this tool, we present novel denial-of...service attacks against the Bit- coin software that exploit low-level implementation ar- tifacts in the Bitcoin reference client; our determinis- tic

Scalable Management of Enterprise and Data-Center Networks

DTIC Science & Technology

2011-09-01

To the best of our knowledge , there is no systematic and efficient solution for handling overlapping wildcard rules in network-wide flow- management ...and D. Maltz, “Unraveling the complexity of network management ,” in NSDI, 2009. [4] P. Mahadevan, P. Sharma, S. Banerjee, and P. Ranganathan , “A...Scalable Management of Enterprise and Data-Center Networks Minlan Yu A Dissertation Presented to the Faculty of Princeton University in Candidacy for

Layered Architectures for Quantum Computers and Quantum Repeaters

NASA Astrophysics Data System (ADS)

Jones, Nathan C.

This chapter examines how to organize quantum computers and repeaters using a systematic framework known as layered architecture, where machine control is organized in layers associated with specialized tasks. The framework is flexible and could be used for analysis and comparison of quantum information systems. To demonstrate the design principles in practice, we develop architectures for quantum computers and quantum repeaters based on optically controlled quantum dots, showing how a myriad of technologies must operate synchronously to achieve fault-tolerance. Optical control makes information processing in this system very fast, scalable to large problem sizes, and extendable to quantum communication.

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

Katti, Amogh; Di Fatta, Giuseppe; Naughton, Thomas

Future extreme-scale high-performance computing systems will be required to work under frequent component failures. The MPI Forum s User Level Failure Mitigation proposal has introduced an operation, MPI Comm shrink, to synchronize the alive processes on the list of failed processes, so that applications can continue to execute even in the presence of failures by adopting algorithm-based fault tolerance techniques. This MPI Comm shrink operation requires a failure detection and consensus algorithm. This paper presents three novel failure detection and consensus algorithms using Gossiping. The proposed algorithms were implemented and tested using the Extreme-scale Simulator. The results show that inmore » all algorithms the number of Gossip cycles to achieve global consensus scales logarithmically with system size. The second algorithm also shows better scalability in terms of memory and network bandwidth usage and a perfect synchronization in achieving global consensus. The third approach is a three-phase distributed failure detection and consensus algorithm and provides consistency guarantees even in very large and extreme-scale systems while at the same time being memory and bandwidth efficient.« less

An open-source, extensible system for laboratory timing and control

NASA Astrophysics Data System (ADS)

Gaskell, Peter E.; Thorn, Jeremy J.; Alba, Sequoia; Steck, Daniel A.

2009-11-01

We describe a simple system for timing and control, which provides control of analog, digital, and radio-frequency signals. Our system differs from most common laboratory setups in that it is open source, built from off-the-shelf components, synchronized to a common and accurate clock, and connected over an Ethernet network. A simple bus architecture facilitates creating new and specialized devices with only moderate experience in circuit design. Each device operates independently, requiring only an Ethernet network connection to the controlling computer, a clock signal, and a trigger signal. This makes the system highly robust and scalable. The devices can all be connected to a single external clock, allowing synchronous operation of a large number of devices for situations requiring precise timing of many parallel control and acquisition channels. Provided an accurate enough clock, these devices are capable of triggering events separated by one day with near-microsecond precision. We have achieved precisions of ˜0.1 ppb (parts per 109) over 16 s.

A versatile scalable PET processing system

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

H. Dong, A. Weisenberger, J. McKisson, Xi Wenze, C. Cuevas, J. Wilson, L. Zukerman

2011-06-01

Positron Emission Tomography (PET) historically has major clinical and preclinical applications in cancerous oncology, neurology, and cardiovascular diseases. Recently, in a new direction, an application specific PET system is being developed at Thomas Jefferson National Accelerator Facility (Jefferson Lab) in collaboration with Duke University, University of Maryland at Baltimore (UMAB), and West Virginia University (WVU) targeted for plant eco-physiology research. The new plant imaging PET system is versatile and scalable such that it could adapt to several plant imaging needs - imaging many important plant organs including leaves, roots, and stems. The mechanical arrangement of the detectors is designed tomore » accommodate the unpredictable and random distribution in space of the plant organs without requiring the plant be disturbed. Prototyping such a system requires a new data acquisition system (DAQ) and data processing system which are adaptable to the requirements of these unique and versatile detectors.« less

Innovative Methods for Providing Instruction to Distance Students Using Technology.

ERIC Educational Resources Information Center

Pival, Paul R.; Tunon, Johanna

2001-01-01

Examines three innovative methods tried at Nova Southeastern University for providing quality bibliographic instruction to distance students: one synchronous, one asynchronous, and one that combined features from both synchronous and asynchronous methods of delivering instruction. Topics include compressed video, collaborative groupware, streaming…

Scalable Biomarker Discovery for Diverse High-Dimensional Phenotypes

DTIC Science & Technology

2015-11-23

bytes: Computational analysis methods for microbial communities," University of Oregon BioBE center seminar. Eugene, OR, 2013 35- "From microbial...analysis methods for microbial communities," University of Oregon BioBE center seminar. Eugene, OR, 2013 • "From microbial surveys to mechanisms of

Scalable and uniform 1D nanoparticles by synchronous polymerization, crystallization and self-assembly

NASA Astrophysics Data System (ADS)

Boott, Charlotte E.; Gwyther, Jessica; Harniman, Robert L.; Hayward, Dominic W.; Manners, Ian

2017-08-01

The preparation of well-defined nanoparticles based on soft matter, using solution-processing techniques on a commercially viable scale, is a major challenge of widespread importance. Self-assembly of block copolymers in solvents that selectively solvate one of the segments provides a promising route to core-corona nanoparticles (micelles) with a wide range of potential uses. Nevertheless, significant limitations to this approach also exist. For example, the solution processing of block copolymers generally follows a separate synthesis step and is normally performed at high dilution. Moreover, non-spherical micelles—which are promising for many applications—are generally difficult to access, samples are polydisperse and precise dimensional control is not possible. Here we demonstrate the formation of platelet and cylindrical micelles at concentrations up to 25% solids via a one-pot approach—starting from monomers—that combines polymerization-induced and crystallization-driven self-assembly. We also show that performing the procedure in the presence of small seed micelles allows the scalable formation of low dispersity samples of cylindrical micelles of controlled length up to three micrometres.

Hybrid Speaker Recognition Using Universal Acoustic Model

NASA Astrophysics Data System (ADS)

Nishimura, Jun; Kuroda, Tadahiro

We propose a novel speaker recognition approach using a speaker-independent universal acoustic model (UAM) for sensornet applications. In sensornet applications such as “Business Microscope”, interactions among knowledge workers in an organization can be visualized by sensing face-to-face communication using wearable sensor nodes. In conventional studies, speakers are detected by comparing energy of input speech signals among the nodes. However, there are often synchronization errors among the nodes which degrade the speaker recognition performance. By focusing on property of the speaker's acoustic channel, UAM can provide robustness against the synchronization error. The overall speaker recognition accuracy is improved by combining UAM with the energy-based approach. For 0.1s speech inputs and 4 subjects, speaker recognition accuracy of 94% is achieved at the synchronization error less than 100ms.

Cluster synchronization induced by one-node clusters in networks with asymmetric negative couplings

NASA Astrophysics Data System (ADS)

Zhang, Jianbao; Ma, Zhongjun; Zhang, Gang

2013-12-01

This paper deals with the problem of cluster synchronization in networks with asymmetric negative couplings. By decomposing the coupling matrix into three matrices, and employing Lyapunov function method, sufficient conditions are derived for cluster synchronization. The conditions show that the couplings of multi-node clusters from one-node clusters have beneficial effects on cluster synchronization. Based on the effects of the one-node clusters, an effective and universal control scheme is put forward for the first time. The obtained results may help us better understand the relation between cluster synchronization and cluster structures of the networks. The validity of the control scheme is confirmed through two numerical simulations, in a network with no cluster structure and in a scale-free network.

The design of multiplayer online video game systems

NASA Astrophysics Data System (ADS)

Hsu, Chia-chun A.; Ling, Jim; Li, Qing; Kuo, C.-C. J.

2003-11-01

The distributed Multiplayer Online Game (MOG) system is complex since it involves technologies in computer graphics, multimedia, artificial intelligence, computer networking, embedded systems, etc. Due to the large scope of this problem, the design of MOG systems has not yet been widely addressed in the literatures. In this paper, we review and analyze the current MOG system architecture followed by evaluation. Furthermore, we propose a clustered-server architecture to provide a scalable solution together with the region oriented allocation strategy. Two key issues, i.e. interesting management and synchronization, are discussed in depth. Some preliminary ideas to deal with the identified problems are described.

Cooperative Learning for Distributed In-Network Traffic Classification

NASA Astrophysics Data System (ADS)

Joseph, S. B.; Loo, H. R.; Ismail, I.; Andromeda, T.; Marsono, M. N.

2017-04-01

Inspired by the concept of autonomic distributed/decentralized network management schemes, we consider the issue of information exchange among distributed network nodes to network performance and promote scalability for in-network monitoring. In this paper, we propose a cooperative learning algorithm for propagation and synchronization of network information among autonomic distributed network nodes for online traffic classification. The results show that network nodes with sharing capability perform better with a higher average accuracy of 89.21% (sharing data) and 88.37% (sharing clusters) compared to 88.06% for nodes without cooperative learning capability. The overall performance indicates that cooperative learning is promising for distributed in-network traffic classification.

A Full Mesh ATCA-based General Purpose Data Processing Board (Pulsar II)

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

Ajuha, S.

The Pulsar II is a custom ATCA full mesh enabled FPGA-based processor board which has been designed with the goal of creating a scalable architecture abundant in flexible, non-blocking, high bandwidth interconnections. The design has been motivated by silicon-based tracking trigger needs for LHC experiments. In this technical memo we describe the Pulsar II hardware and its performance, such as the performance test results with full mesh backplanes from different vendors, how the backplane is used for the development of low-latency time-multiplexed data transfer schemes and how the inter-shelf and intra-shelf synchronization works.

The Effect of Synchronous and Asynchronous Participation on Students' Performance in Online Accounting Courses

ERIC Educational Resources Information Center

Duncan, Keith; Kenworthy, Amy; McNamara, Ray

2012-01-01

This article examines the relationship between MBA students' performance and participation in two online environments: a synchronous forum (chat room) and an asynchronous forum (discussion board) at an Australian university. The "quality" and "quantity" of students' participation is used to predict their final examination and…

Establishing and maintaining a satellite campus connected by synchronous video conferencing.

PubMed

Fox, Brent I; McDonough, Sharon L; McConatha, Barry J; Marlowe, Karen F

2011-06-10

Pharmacy education has experienced substantial growth in the number of new schools and existing schools establishing satellite campuses. Several models have previously been used to connect primary and satellite campuses. We describe the Auburn University Harrison School of Pharmacy's (AUHSOP's) experiences using synchronous video conferencing between the Auburn University campus in Auburn and a satellite campus in Mobile, Alabama. We focus on the technology considerations related to planning, construction, implementation, and continued use of the various resources that support our program. Students' perceptions of their experiences related to technology also are described.

Supermultiplicative Speedups of Probabilistic Model-Building Genetic Algorithms

DTIC Science & Technology

2009-02-01

physicists as well as practitioners in evolutionary computation. The project was later extended to the one-dimensional SK spin glass with power -law... Brasil ) 10. Yuji Sato (Hosei University, Japan) 11. Shunsukc Saruwatari (Tokyo University, Japan) 12. Jian-Hung Chen (Feng Chia University, Taiwan...scalability. In A. Tiwari, J. Knowlcs, E. Avincri, K. Dahal, and R. Roy (Eds.) Applications of Soft Computing: Recent Trends. Berlin: Springer (2006

Experimental realization of universal geometric quantum gates with solid-state spins.

PubMed

Zu, C; Wang, W-B; He, L; Zhang, W-G; Dai, C-Y; Wang, F; Duan, L-M

2014-10-02

Experimental realization of a universal set of quantum logic gates is the central requirement for the implementation of a quantum computer. In an 'all-geometric' approach to quantum computation, the quantum gates are implemented using Berry phases and their non-Abelian extensions, holonomies, from geometric transformation of quantum states in the Hilbert space. Apart from its fundamental interest and rich mathematical structure, the geometric approach has some built-in noise-resilience features. On the experimental side, geometric phases and holonomies have been observed in thermal ensembles of liquid molecules using nuclear magnetic resonance; however, such systems are known to be non-scalable for the purposes of quantum computing. There are proposals to implement geometric quantum computation in scalable experimental platforms such as trapped ions, superconducting quantum bits and quantum dots, and a recent experiment has realized geometric single-bit gates in a superconducting system. Here we report the experimental realization of a universal set of geometric quantum gates using the solid-state spins of diamond nitrogen-vacancy centres. These diamond defects provide a scalable experimental platform with the potential for room-temperature quantum computing, which has attracted strong interest in recent years. Our experiment shows that all-geometric and potentially robust quantum computation can be realized with solid-state spin quantum bits, making use of recent advances in the coherent control of this system.

Paths for World-Class Universities in Agricultural Science

ERIC Educational Resources Information Center

Liu, Zhimin; Kipchumba, Simon Kibet; Liu, Lu

2016-01-01

The top-ranking world-class universities in agricultural science denote those universities which are globally popular with agriculture-related subjects. The paper synthesizes the results of three different ranking scales (NTU, QS and ARWU) of top 50 universities in agriculture subject in 2013. The overlapped parts have been synchronized to derive…

Keeping the Beat: A Large Sample Study of Bouncing and Clapping to Music

PubMed Central

Tranchant, Pauline; Vuvan, Dominique T.; Peretz, Isabelle

2016-01-01

The vast majority of humans move in time with a musical beat. This behaviour has been mostly studied through finger-tapping synchronization. Here, we evaluate naturalistic synchronization responses to music–bouncing and clapping–in 100 university students. Their ability to match the period of their bounces and claps to those of a metronome and musical clips varying in beat saliency was assessed. In general, clapping was better synchronized with the beat than bouncing, suggesting that the choice of a specific movement type is an important factor to consider in the study of sensorimotor synchronization processes. Performance improved as a function of beat saliency, indicating that beat abstraction plays a significant role in synchronization. Fourteen percent of the population exhibited marked difficulties with matching the beat. Yet, at a group level, poor synchronizers showed similar sensitivity to movement type and beat saliency as normal synchronizers. These results suggest the presence of quantitative rather than qualitative variations when losing the beat. PMID:27471854

Using synchronous software in Web-based nursing courses.

PubMed

Little, Barbara Battin; Passmore, Denise; Schullo, Shauna

2006-01-01

To promote learning and enhance immediacy and satisfaction, a college of nursing at a large research I southern university undertook a pilot project to incorporate synchronous classroom software into an ongoing online program. Two synchronous class sessions using voice over Internet protocol were offered in the Community/Public Health Nursing course through Elluminate Live! Upon conclusion of the lecture, students were divided into breakout groups to work on group projects. Surveys were administered to the students and faculty before and after the class sessions. Evaluation of the pedagogical strategies used in the synchronous sessions was conducted by instructional technology faculty. Students in the pilot group reported higher levels of satisfaction with the Web-based course with synchronous sessions. In addition, students reported that group time at the end of the session was helpful for completing group projects. A majority responded that synchronous session activities and assignments facilitated their understanding of course content. This article presents a description of the synchronous classroom pilot project along with recommendations for implementation and pedagogical approaches.

Epidemic failure detection and consensus for extreme parallelism

DOE PAGES

Katti, Amogh; Di Fatta, Giuseppe; Naughton, Thomas; ...

2017-02-01

Future extreme-scale high-performance computing systems will be required to work under frequent component failures. The MPI Forum s User Level Failure Mitigation proposal has introduced an operation, MPI Comm shrink, to synchronize the alive processes on the list of failed processes, so that applications can continue to execute even in the presence of failures by adopting algorithm-based fault tolerance techniques. This MPI Comm shrink operation requires a failure detection and consensus algorithm. This paper presents three novel failure detection and consensus algorithms using Gossiping. The proposed algorithms were implemented and tested using the Extreme-scale Simulator. The results show that inmore » all algorithms the number of Gossip cycles to achieve global consensus scales logarithmically with system size. The second algorithm also shows better scalability in terms of memory and network bandwidth usage and a perfect synchronization in achieving global consensus. The third approach is a three-phase distributed failure detection and consensus algorithm and provides consistency guarantees even in very large and extreme-scale systems while at the same time being memory and bandwidth efficient.« less

Cluster synchronization induced by one-node clusters in networks with asymmetric negative couplings

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

Zhang, Jianbao; Ma, Zhongjun, E-mail: mzj1234402@163.com; Zhang, Gang

2013-12-15

This paper deals with the problem of cluster synchronization in networks with asymmetric negative couplings. By decomposing the coupling matrix into three matrices, and employing Lyapunov function method, sufficient conditions are derived for cluster synchronization. The conditions show that the couplings of multi-node clusters from one-node clusters have beneficial effects on cluster synchronization. Based on the effects of the one-node clusters, an effective and universal control scheme is put forward for the first time. The obtained results may help us better understand the relation between cluster synchronization and cluster structures of the networks. The validity of the control scheme ismore » confirmed through two numerical simulations, in a network with no cluster structure and in a scale-free network.« less

At a Distance: A Comparative Study of Distance Delivery Modalities for PhD Nursing Students

ERIC Educational Resources Information Center

Black, Andrew G.

2010-01-01

This study sought to ascertain and compare the attitudes and perceptions of PhD nursing students attending their coursework through synchronous and asynchronous means at two different universities. Many studies have been performed comparing both synchronous videoconferencing and asynchronous online education with the traditional classroom, but no…

Teaching-Learning Process by Synchronic Communication Tools: The Elluminate Live Case

ERIC Educational Resources Information Center

Santovena-Casal, Sonia Ma

2012-01-01

When integrating a new online tool in university educational system, it is necessary to know its features, applications and functions in depth, advantages and disadvantages, and the results obtained when it has been used by other educational institutions. Synchronous communication tool, "Elluminate Live" can be integrated into a virtual platform…

Are You with Me or Not? Temporal Synchronicity and Transactivity during CSCL

ERIC Educational Resources Information Center

Popov, V.; van Leeuwen, A.; Buis, S. C. A.

2017-01-01

Do the simultaneous alignment of student activities (temporal synchronicity) and students successively building on each other's reasoning (transactivity) predict the quality of collaborative learning products? To address this question, we used a mixed-method approach to study 74 first-year university students who were randomly assigned to work in…

A Case Study of Language Learners' Social Presence in Synchronous CMC

ERIC Educational Resources Information Center

Ko, Chao-Jung

2012-01-01

This study adopts a case study approach to investigate the impacts of synchronous computer-mediated communication (CMC) learning environments on learners' perception of social presence. The participants were twelve French as a foreign language (FFL) beginners in a Taiwanese university. Divided into three groups, they conducted some tasks in three…

Scalable Production of Biosensors Based on Aptamer-Functionalized Graphene for Detection of the HIV drug Tenofovir

NASA Astrophysics Data System (ADS)

Vishnubhotla, Ramya; Ping, Jinglei; Johnson, A. T. Charlie; Charlie Johnson Group Team

Graphene field effect transistors (GFETs) are of great interest for biosensing applications, and have shown promising results for small molecular detection due to high sensitivity and electron mobility. We describe the fabrication of a scalable array of GFETs through traditional photolithography using lab-grown graphene via chemical vapor deposition (CVD) for drug detection with an all-electronic read-out. Sensor fabrication produced 52 devices per 2 x 2 cm area, with a yield of over 90%. Our biosensors use a commercially-obtained aptamer, verified to bind to graphene via AFM, to bind to the molecules of the drug Tenofovir, a medication currently used for HIV treatment, and have proven to detect concentrations at 1 ng/mL, 10^3 times lower than standard medical methods. We noted a concentration-dependent shift in the Dirac voltage for Tenofovir, and testing control drugs showed that the aptamer was only highly selective in binding to Tenofovir itself. These results are promising for potential clinical testing with urine samples, as our method is scalable and non-invasive. This work is funded by NIH through the Center for AIDS Research at the University of Pennsylvania. Center for AIDS Research at the University of Pennsylvania.

Controlador para un Reloj GPS de Referencia en el Protocolo NTP

NASA Astrophysics Data System (ADS)

Hauscarriaga, F.; Bareilles, F. A.

The synchronization between computers in a local network plays a very important role on enviroments similar to IAR. Calculations for exact time are needed before, during and after an observation. For this purpose the IAR's GNU/Linux Software Development Team implemented a driver inside NTP protocol (an internet standard for time synchronization of computers) for a GPS receiver acquired a few years ago by IAR, which did not have support in such protocol. Today our Institute has a stable and reliable time base synchronized to atomic clocks on board GPS Satellites according to computers's synchronization standard, offering precise time services to all scientific community and particularly to the University of La Plata. FULL TEXT IN SPANISH

Establishing and Maintaining a Satellite Campus Connected by Synchronous Video Conferencing

PubMed Central

Fox, Brent I.; McDonough, Sharon L.; McConatha, Barry J.; Marlowe, Karen F.

2011-01-01

Pharmacy education has experienced substantial growth in the number of new schools and existing schools establishing satellite campuses. Several models have previously been used to connect primary and satellite campuses. We describe the Auburn University Harrison School of Pharmacy's (AUHSOP's) experiences using synchronous video conferencing between the Auburn University campus in Auburn and a satellite campus in Mobile, Alabama. We focus on the technology considerations related to planning, construction, implementation, and continued use of the various resources that support our program. Students’ perceptions of their experiences related to technology also are described. PMID:21829265

Educational Transformation in Upper-Division Physics: The Science Education Initiative Model, Outcomes, and Lessons Learned

ERIC Educational Resources Information Center

Chasteen, Stephanie V.; Wilcox, Bethany; Caballero, Marcos D.; Perkins, Katherine K.; Pollock, Steven J.; Wieman, Carl E.

2015-01-01

In response to the need for a scalable, institutionally supported model of educational change, the Science Education Initiative (SEI) was created as an experiment in transforming course materials and faculty practices at two institutions--University of Colorado Boulder (CU) and University of British Columbia. We find that this departmentally…

Investigating Student Attitudes toward a Synchronous, Online Graduate Course in a Multi-User Virtual Learning Environment

ERIC Educational Resources Information Center

Annetta, Leonard; Murray, Marshall; Gull Laird, Shelby; Bohr, Stephanie; Park, John

2008-01-01

This article describes a graduate distance education course at North Carolina State University, which combined science content and pedagogy with video game design. The course was conducted entirely in a synchronous, online, Virtual Learning Environment (VLE) through the ActiveWorlds[TM] platform. Inservice teachers enrolled as graduate students in…

Synchronous Computer-Mediated Dynamic Assessment: A Case Study of L2 Spanish Past Narration

ERIC Educational Resources Information Center

Darhower, Mark Anthony

2014-01-01

In this study, dynamic assessment is employed to help understand the developmental processes of two university Spanish learners as they produce a series of past narrations in a synchronous computer mediated environment. The assessments were conducted in six weekly one-hour chat sessions about various scenes of a Spanish language film. The analysis…

The Effects of Synchronous and Asynchronous Distance Education: A Meta-Analytical Assessment of Simonson's "Equivalency Theory"

ERIC Educational Resources Information Center

Bernard, Robert M.; Abrami, Philip C.; Wade, Anne; Borokhovski, Evgueni; Lou, Yiping

2004-01-01

Simonson, Schlosser and Hanson (1999) argue that a new theory called "equivalency theory" is needed to account for the unique features of the "teleconferencing" (synchronous) model of DE that is prevalent in many North American universities. Based on a comprehensive meta-analysis of the comparative literature of DE (Bernard,…

Reviving a Digital Dinosaur: Text-Only Synchronous Online Chats and Peer Tutoring in Communication Centers

ERIC Educational Resources Information Center

Schwartzman, Roy

2013-01-01

A qualitative and quantitative content analysis was conducted of all text-based synchronous online chats at an oral communication peer tutoring center throughout a semester. As a comparative benchmark, chats at the same university's main library were analyzed over the same time period. The library's chats were much more heavily weighted toward…

Private Turns: A Student's Off-Screen Behaviors during Synchronous Online Japanese Instruction

ERIC Educational Resources Information Center

Suzuki, Satomi

2013-01-01

Although distance language education has been widely adopted in university learning, very few researchers to date have looked at off-screen behaviors of second/foreign language learners in their physical environments while they engage in synchronous (real-time) online courses. This study examined one focal student's off-screen behaviors while…

Mechanism for Promoting Motivation, Confidence, and Autonomy through Synchronic Communication Sessions in Virtual Learning Environments

ERIC Educational Resources Information Center

Valencia, Jorge Andrick Parra; Dallos, Adriana Rocío Lizcano; Ballesteros, Eliécer Pineda

2017-01-01

This study presents a mechanism which explains the effect of synchronous communication on students' perception of the training process in virtual learning methodology used in a postgraduate programme at the University of Santander. We use System Dynamics to design a mechanism that integrates motivation, confidence, trust, and autonomy in students.…

A Case Study of Integrating Interwise: Interaction, Internet Self-Efficacy, and Satisfaction in Synchronous Online Learning Environments

ERIC Educational Resources Information Center

Kuo, Yu-Chun; Walker, Andrew E.; Belland, Brian R.; Schroder, Kerstin E. E.; Kuo, Yu-Tung

2014-01-01

This paper reports research on the implementation of a web-based videoconferencing tool (Interwise) for synchronous learning sessions on an industrial technology course offered through a university in northern Taiwan. The participants included undergraduate students from the same course offered in two different semesters. We investigated students'…

On Synchronous Distance Teaching in a Mathematics MS (Master of Science) Program

ERIC Educational Resources Information Center

Li, Kuiyuan; Amin, Raid; Uvah, Josaphat

2011-01-01

A fully online graduate program that was developed at the UWF (University of West Florida) has been successfully implemented using synchronous instruction since fall 2009. The hybrid nature of the developed model has proven to be of benefit to both face-to-face and distance students. Aside from the robustness of students' discussions and…

Exploring Meaning Negotiation Patterns in Synchronous Audio and Video Conferencing English Classes in China

ERIC Educational Resources Information Center

Li, Chenxi; Wu, Ligao; Li, Chen; Tang, Jinlan

2017-01-01

This work-in-progress doctoral research project aims to identify meaning negotiation patterns in synchronous audio and video Computer-Mediated Communication (CMC) environments based on the model of CMC text chat proposed by Smith (2003). The study was conducted in the Institute of Online Education at Beijing Foreign Studies University. Four dyads…

Dynamical Formation of Kerr Black Holes with Synchronized Hair: An Analytic Model.

PubMed

Herdeiro, Carlos A R; Radu, Eugen

2017-12-29

East and Pretorius have successfully evolved, using fully nonlinear numerical simulations, the superradiant instability of the Kerr black hole (BH) triggered by a massive, complex vector field. Evolutions terminate in stationary states of a vector field condensate synchronized with a rotating BH horizon. We show that these end points are fundamental states of Kerr BHs with synchronized Proca hair. Motivated by the "experimental data" from these simulations, we suggest a universal (i.e., field-spin independent), analytic model for the subset of BHs with synchronized hair that possess a quasi-Kerr horizon, applicable in the weak hair regime. Comparing this model with fully nonlinear numerical solutions of BHs with a synchronized scalar or Proca hair, we show that the model is accurate for hairy BHs that may emerge dynamically from superradiance, whose domain we identify.

Dynamical Formation of Kerr Black Holes with Synchronized Hair: An Analytic Model

NASA Astrophysics Data System (ADS)

Herdeiro, Carlos A. R.; Radu, Eugen

2017-12-01

East and Pretorius have successfully evolved, using fully nonlinear numerical simulations, the superradiant instability of the Kerr black hole (BH) triggered by a massive, complex vector field. Evolutions terminate in stationary states of a vector field condensate synchronized with a rotating BH horizon. We show that these end points are fundamental states of Kerr BHs with synchronized Proca hair. Motivated by the "experimental data" from these simulations, we suggest a universal (i.e., field-spin independent), analytic model for the subset of BHs with synchronized hair that possess a quasi-Kerr horizon, applicable in the weak hair regime. Comparing this model with fully nonlinear numerical solutions of BHs with a synchronized scalar or Proca hair, we show that the model is accurate for hairy BHs that may emerge dynamically from superradiance, whose domain we identify.

On noise and the performance benefit of nonblocking collectives

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

Widener, Patrick M.; Levy, Scott; Ferreira, Kurt B.

Relaxed synchronization offers the potential of maintaining application scalability by allowing many processes to make independent progress when some processes suffer delays. Yet, the benefits of this approach in important parallel workloads have not been investigated in detail. In this paper, we use a validated simulation approach to explore the noise mitigation effects of idealized nonblocking collectives in workloads where these collectives are a major contributor to total execution time. In conclusion, although nonblocking collectives are unlikely to provide significant noise mitigation to applications in the low-OS-noise environments expected in next-generation HPC systems, we show that they can potentially improvemore » application runtime with respect to other noise types.« less

On noise and the performance benefit of nonblocking collectives

DOE PAGES

Widener, Patrick M.; Levy, Scott; Ferreira, Kurt B.; ...

2015-11-02

Relaxed synchronization offers the potential of maintaining application scalability by allowing many processes to make independent progress when some processes suffer delays. Yet, the benefits of this approach in important parallel workloads have not been investigated in detail. In this paper, we use a validated simulation approach to explore the noise mitigation effects of idealized nonblocking collectives in workloads where these collectives are a major contributor to total execution time. In conclusion, although nonblocking collectives are unlikely to provide significant noise mitigation to applications in the low-OS-noise environments expected in next-generation HPC systems, we show that they can potentially improvemore » application runtime with respect to other noise types.« less

Stochastic Multiscale Analysis and Design of Engine Disks

DTIC Science & Technology

2010-07-28

shown recently to fail when used with data-driven non-linear stochastic input models (KPCA, IsoMap, etc.). Need for scalable exascale computing algorithms Materials Process Design and Control Laboratory Cornell University

Optimization of atmospheric transport models on HPC platforms

NASA Astrophysics Data System (ADS)

de la Cruz, Raúl; Folch, Arnau; Farré, Pau; Cabezas, Javier; Navarro, Nacho; Cela, José María

2016-12-01

The performance and scalability of atmospheric transport models on high performance computing environments is often far from optimal for multiple reasons including, for example, sequential input and output, synchronous communications, work unbalance, memory access latency or lack of task overlapping. We investigate how different software optimizations and porting to non general-purpose hardware architectures improve code scalability and execution times considering, as an example, the FALL3D volcanic ash transport model. To this purpose, we implement the FALL3D model equations in the WARIS framework, a software designed from scratch to solve in a parallel and efficient way different geoscience problems on a wide variety of architectures. In addition, we consider further improvements in WARIS such as hybrid MPI-OMP parallelization, spatial blocking, auto-tuning and thread affinity. Considering all these aspects together, the FALL3D execution times for a realistic test case running on general-purpose cluster architectures (Intel Sandy Bridge) decrease by a factor between 7 and 40 depending on the grid resolution. Finally, we port the application to Intel Xeon Phi (MIC) and NVIDIA GPUs (CUDA) accelerator-based architectures and compare performance, cost and power consumption on all the architectures. Implications on time-constrained operational model configurations are discussed.

Efficient and Scalable Cross-Matching of (Very) Large Catalogs

NASA Astrophysics Data System (ADS)

Pineau, F.-X.; Boch, T.; Derriere, S.

2011-07-01

Whether it be for building multi-wavelength datasets from independent surveys, studying changes in objects luminosities, or detecting moving objects (stellar proper motions, asteroids), cross-catalog matching is a technique widely used in astronomy. The need for efficient, reliable and scalable cross-catalog matching is becoming even more pressing with forthcoming projects which will produce huge catalogs in which astronomers will dig for rare objects, perform statistical analysis and classification, or real-time transients detection. We have developed a formalism and the corresponding technical framework to address the challenge of fast cross-catalog matching. Our formalism supports more than simple nearest-neighbor search, and handles elliptical positional errors. Scalability is improved by partitioning the sky using the HEALPix scheme, and processing independently each sky cell. The use of multi-threaded two-dimensional kd-trees adapted to managing equatorial coordinates enables efficient neighbor search. The whole process can run on a single computer, but could also use clusters of machines to cross-match future very large surveys such as GAIA or LSST in reasonable times. We already achieve performances where the 2MASS (˜470M sources) and SDSS DR7 (˜350M sources) can be matched on a single machine in less than 10 minutes. We aim at providing astronomers with a catalog cross-matching service, available on-line and leveraging on the catalogs present in the VizieR database. This service will allow users both to access pre-computed cross-matches across some very large catalogs, and to run customized cross-matching operations. It will also support VO protocols for synchronous or asynchronous queries.

Differences in Electronic Exchanges in Synchronous and Asynchronous Computer-Mediated Communication: The Effect of Culture as a Mediating Variable

ERIC Educational Resources Information Center

Angeli, Charoula; Schwartz, Neil H.

2016-01-01

Two hundred and eighty undergraduates from universities in two countries were asked to read didactic material, and then think and write about potential solutions to an ill-defined problem. The writing was conducted within a synchronous or asynchronous computer-mediated communication (CMC) environment. Asynchronous CMC took the form of email…

Improving Music Teaching and Learning through Online Service: A Case Study of a Synchronous Online Teaching Internship

ERIC Educational Resources Information Center

Pike, Pamela D.

2017-01-01

This case study explored the potential for using a synchronous online piano teaching internship as a service-learning project for graduate pedagogy interns. In partnership with the university, a local music retailer, and a local middle school, three pedagogy interns taught beginning piano to underprivileged teenaged students for 8 weeks. All…

In Bed with the Library: A Critical Exploration of Embedded Librarianship at the City University of New York

ERIC Educational Resources Information Center

Pollack, Julia

2017-01-01

This project considers the efficacy and scalability of embedded librarianship initiatives within the City University of New York (CUNY) library system and presents findings of an original research study conducted in 2015. Through an analysis of recent LIS literature on embedment, response data from a survey of librarians, and a selection of…

Online Distance Teaching of Undergraduate Finance: A Case for Musashi University and Konan University, Japan

ERIC Educational Resources Information Center

Kubota, Keiichi; Fujikawa, Kiyoshi

2007-01-01

We implemented a synchronous distance course entitled: Introductory Finance designed for undergraduate students. This course was held between two Japanese universities. Stable Internet connections allowing minimum delay and minimum interruptions of the audio-video streaming signals were used. Students were equipped with their own PCs with…

Statistically rigorous calculations do not support common input and long-term synchronization of motor-unit firings

PubMed Central

Kline, Joshua C.

2014-01-01

Over the past four decades, various methods have been implemented to measure synchronization of motor-unit firings. In this work, we provide evidence that prior reports of the existence of universal common inputs to all motoneurons and the presence of long-term synchronization are misleading, because they did not use sufficiently rigorous statistical tests to detect synchronization. We developed a statistically based method (SigMax) for computing synchronization and tested it with data from 17,736 motor-unit pairs containing 1,035,225 firing instances from the first dorsal interosseous and vastus lateralis muscles—a data set one order of magnitude greater than that reported in previous studies. Only firing data, obtained from surface electromyographic signal decomposition with >95% accuracy, were used in the study. The data were not subjectively selected in any manner. Because of the size of our data set and the statistical rigor inherent to SigMax, we have confidence that the synchronization values that we calculated provide an improved estimate of physiologically driven synchronization. Compared with three other commonly used techniques, ours revealed three types of discrepancies that result from failing to use sufficient statistical tests necessary to detect synchronization. 1) On average, the z-score method falsely detected synchronization at 16 separate latencies in each motor-unit pair. 2) The cumulative sum method missed one out of every four synchronization identifications found by SigMax. 3) The common input assumption method identified synchronization from 100% of motor-unit pairs studied. SigMax revealed that only 50% of motor-unit pairs actually manifested synchronization. PMID:25210152

Scalable implementation of boson sampling with trapped ions.

PubMed

Shen, C; Zhang, Z; Duan, L-M

2014-02-07

Boson sampling solves a classically intractable problem by sampling from a probability distribution given by matrix permanents. We propose a scalable implementation of boson sampling using local transverse phonon modes of trapped ions to encode the bosons. The proposed scheme allows deterministic preparation and high-efficiency readout of the bosons in the Fock states and universal mode mixing. With the state-of-the-art trapped ion technology, it is feasible to realize boson sampling with tens of bosons by this scheme, which would outperform the most powerful classical computers and constitute an effective disproof of the famous extended Church-Turing thesis.

SCaLeM: A Framework for Characterizing and Analyzing Execution Models

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

Chavarría-Miranda, Daniel; Manzano Franco, Joseph B.; Krishnamoorthy, Sriram

2014-10-13

As scalable parallel systems evolve towards more complex nodes with many-core architectures and larger trans-petascale & upcoming exascale deployments, there is a need to understand, characterize and quantify the underlying execution models being used on such systems. Execution models are a conceptual layer between applications & algorithms and the underlying parallel hardware and systems software on which those applications run. This paper presents the SCaLeM (Synchronization, Concurrency, Locality, Memory) framework for characterizing and execution models. SCaLeM consists of three basic elements: attributes, compositions and mapping of these compositions to abstract parallel systems. The fundamental Synchronization, Concurrency, Locality and Memory attributesmore » are used to characterize each execution model, while the combinations of those attributes in the form of compositions are used to describe the primitive operations of the execution model. The mapping of the execution model’s primitive operations described by compositions, to an underlying abstract parallel system can be evaluated quantitatively to determine its effectiveness. Finally, SCaLeM also enables the representation and analysis of applications in terms of execution models, for the purpose of evaluating the effectiveness of such mapping.« less

Stability Assessment of a System Comprising a Single Machine and Inverter with Scalable Ratings

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

Johnson, Brian B; Lin, Yashen; Gevorgian, Vahan

Synchronous machines have traditionally acted as the foundation of large-scale electrical infrastructures and their physical properties have formed the cornerstone of system operations. However, with the increased integration of distributed renewable resources and energy-storage technologies, there is a need to systematically acknowledge the dynamics of power-electronics inverters - the primary energy-conversion interface in such systems - in all aspects of modeling, analysis, and control of the bulk power network. In this paper, we assess the properties of coupled machine-inverter systems by studying an elementary system comprised of a synchronous generator, three-phase inverter, and a load. The inverter model is formulatedmore » such that its power rating can be scaled continuously across power levels while preserving its closed-loop response. Accordingly, the properties of the machine-inverter system can be assessed for varying ratios of machine-to-inverter power ratings. After linearizing the model and assessing its eigenvalues, we show that system stability is highly dependent on the inverter current controller and machine exciter, thus uncovering a key concern with mixed machine-inverter systems and motivating the need for next-generation grid-stabilizing inverter controls.« less

A generic interface to reduce the efficiency-stability-cost gap of perovskite solar cells

NASA Astrophysics Data System (ADS)

Hou, Yi; Du, Xiaoyan; Scheiner, Simon; McMeekin, David P.; Wang, Zhiping; Li, Ning; Killian, Manuela S.; Chen, Haiwei; Richter, Moses; Levchuk, Ievgen; Schrenker, Nadine; Spiecker, Erdmann; Stubhan, Tobias; Luechinger, Norman A.; Hirsch, Andreas; Schmuki, Patrik; Steinrück, Hans-Peter; Fink, Rainer H.; Halik, Marcus; Snaith, Henry J.; Brabec, Christoph J.

2017-12-01

A major bottleneck delaying the further commercialization of thin-film solar cells based on hybrid organohalide lead perovskites is interface loss in state-of-the-art devices. We present a generic interface architecture that combines solution-processed, reliable, and cost-efficient hole-transporting materials without compromising efficiency, stability, or scalability of perovskite solar cells. Tantalum-doped tungsten oxide (Ta-WOx)/conjugated polymer multilayers offer a surprisingly small interface barrier and form quasi-ohmic contacts universally with various scalable conjugated polymers. In a simple device with regular planar architecture and a self-assembled monolayer, Ta-WOx-doped interface-based perovskite solar cells achieve maximum efficiencies of 21.2% and offer more than 1000 hours of light stability. By eliminating additional ionic dopants, these findings open up the entire class of organics as scalable hole-transporting materials for perovskite solar cells.

Complex transitions between spike, burst or chaos synchronization states in coupled neurons with coexisting bursting patterns

NASA Astrophysics Data System (ADS)

Gu, Hua-Guang; Chen, Sheng-Gen; Li, Yu-Ye

2015-05-01

We investigated the synchronization dynamics of a coupled neuronal system composed of two identical Chay model neurons. The Chay model showed coexisting period-1 and period-2 bursting patterns as a parameter and initial values are varied. We simulated multiple periodic and chaotic bursting patterns with non-(NS), burst phase (BS), spike phase (SS), complete (CS), and lag synchronization states. When the coexisting behavior is near period-2 bursting, the transitions of synchronization states of the coupled system follows very complex transitions that begins with transitions between BS and SS, moves to transitions between CS and SS, and to CS. Most initial values lead to the CS state of period-2 bursting while only a few lead to the CS state of period-1 bursting. When the coexisting behavior is near period-1 bursting, the transitions begin with NS, move to transitions between SS and BS, to transitions between SS and CS, and then to CS. Most initial values lead to the CS state of period-1 bursting but a few lead to the CS state of period-2 bursting. The BS was identified as chaos synchronization. The patterns for NS and transitions between BS and SS are insensitive to initial values. The patterns for transitions between CS and SS and the CS state are sensitive to them. The number of spikes per burst of non-CS bursting increases with increasing coupling strength. These results not only reveal the initial value- and parameter-dependent synchronization transitions of coupled systems with coexisting behaviors, but also facilitate interpretation of various bursting patterns and synchronization transitions generated in the nervous system with weak coupling strength. Project supported by the National Natural Science Foundation of China (Grant Nos. 11372224 and 11402039) and the Fundamental Research Funds for Central Universities designated to Tongji University (Grant No. 1330219127).

From photons to phonons and back: a THz optical memory in diamond.

PubMed

England, D G; Bustard, P J; Nunn, J; Lausten, R; Sussman, B J

2013-12-13

Optical quantum memories are vital for the scalability of future quantum technologies, enabling long-distance secure communication and local synchronization of quantum components. We demonstrate a THz-bandwidth memory for light using the optical phonon modes of a room temperature diamond. This large bandwidth makes the memory compatible with down-conversion-type photon sources. We demonstrate that four-wave mixing noise in this system is suppressed by material dispersion. The resulting noise floor is just 7×10(-3) photons per pulse, which establishes that the memory is capable of storing single quanta. We investigate the principle sources of noise in this system and demonstrate that high material dispersion can be used to suppress four-wave mixing noise in Λ-type systems.

Statistically rigorous calculations do not support common input and long-term synchronization of motor-unit firings.

PubMed

De Luca, Carlo J; Kline, Joshua C

2014-12-01

Over the past four decades, various methods have been implemented to measure synchronization of motor-unit firings. In this work, we provide evidence that prior reports of the existence of universal common inputs to all motoneurons and the presence of long-term synchronization are misleading, because they did not use sufficiently rigorous statistical tests to detect synchronization. We developed a statistically based method (SigMax) for computing synchronization and tested it with data from 17,736 motor-unit pairs containing 1,035,225 firing instances from the first dorsal interosseous and vastus lateralis muscles--a data set one order of magnitude greater than that reported in previous studies. Only firing data, obtained from surface electromyographic signal decomposition with >95% accuracy, were used in the study. The data were not subjectively selected in any manner. Because of the size of our data set and the statistical rigor inherent to SigMax, we have confidence that the synchronization values that we calculated provide an improved estimate of physiologically driven synchronization. Compared with three other commonly used techniques, ours revealed three types of discrepancies that result from failing to use sufficient statistical tests necessary to detect synchronization. 1) On average, the z-score method falsely detected synchronization at 16 separate latencies in each motor-unit pair. 2) The cumulative sum method missed one out of every four synchronization identifications found by SigMax. 3) The common input assumption method identified synchronization from 100% of motor-unit pairs studied. SigMax revealed that only 50% of motor-unit pairs actually manifested synchronization. Copyright © 2014 the American Physiological Society.

Energy-Efficient BOP-Based Beacon Transmission Scheduling in Wireless Sensor Networks

NASA Astrophysics Data System (ADS)

Kim, Eui-Jik; Youm, Sungkwan; Choi, Hyo-Hyun

Many applications in wireless sensor networks (WSNs) require the energy efficiency and scalability. Although IEEE 802.15.4/Zigbee which is being considered as general technology for WSNs enables the low duty-cycling with time synchronization of all the nodes in network, it still suffer from its low scalability due to the beacon frame collision. Recently, various algorithms to resolve this problem are proposed. However, their manners to implement are somewhat ambiguous and the degradation of energy/communication efficiency is serious by the additional overhead. This paper describes an Energy-efficient BOP-based Beacon transmission Scheduling (EBBS) algorithm. EBBS is the centralized approach, in which a resource-sufficient node called as Topology Management Center (TMC) allocates the time slots to transmit a beacon frame to the nodes and manages the active/sleep schedules of them. We also propose EBBS with Adaptive BOPL (EBBS-AB), to adjust the duration to transmit beacon frames in every beacon interval, adaptively. Simulation results show that by using the proposed algorithm, the energy efficiency and the throughput of whole network can be significantly improved. EBBS-AB is also more effective for the network performance when the nodes are uniformly deployed on the sensor field rather than the case of random topologies.

Understanding Graphics on a Scalable Latching Assistive Haptic Display Using a Shape Memory Polymer Membrane.

PubMed

Besse, Nadine; Rosset, Samuel; Zarate, Juan Jose; Ferrari, Elisabetta; Brayda, Luca; Shea, Herbert

2018-01-01

We present a fully latching and scalable 4 × 4 haptic display with 4 mm pitch, 5 s refresh time, 400 mN holding force, and 650 μm displacement per taxel. The display serves to convey dynamic graphical information to blind and visually impaired users. Combining significant holding force with high taxel density and large amplitude motion in a very compact overall form factor was made possible by exploiting the reversible, fast, hundred-fold change in the stiffness of a thin shape memory polymer (SMP) membrane when heated above its glass transition temperature. Local heating is produced using an addressable array of 3 mm in diameter stretchable microheaters patterned on the SMP. Each taxel is selectively and independently actuated by synchronizing the local Joule heating with a single pressure supply. Switching off the heating locks each taxel into its position (up or down), enabling holding any array configuration with zero power consumption. A 3D-printed pin array is mounted over the SMP membrane, providing the user with a smooth and room temperature array of movable pins to explore by touch. Perception tests were carried out with 24 blind users resulting in 70 percent correct pattern recognition over a 12-word tactile dictionary.

Development and test of the DAQ system for a Micromegas prototype to be installed in the ATLAS experiment

NASA Astrophysics Data System (ADS)

Bianco, M.; Martoiu, S.; Sidiropoulou, O.; Zibell, A.

2015-12-01

A Micromegas (MM) quadruplet prototype with an active area of 0.5 m2 that adopts the general design foreseen for the upgrade of the innermost forward muon tracking systems (Small Wheels) of the ATLAS detector in 2018-2019, has been built at CERN and is going to be tested in the ATLAS cavern environment during the LHC RUN-II period 2015-2017. The integration of this prototype detector into the ATLAS data acquisition system using custom ATCA equipment is presented. An ATLAS compatible Read Out Driver (ROD) based on the Scalable Readout System (SRS), the Scalable Readout Unit (SRU), will be used in order to transmit the data after generating valid event fragments to the high-level Read Out System (ROS). The SRU will be synchronized with the LHC bunch crossing clock (40.08 MHz) and will receive the Level-1 trigger signals from the Central Trigger Processor (CTP) through the TTCrx receiver ASIC. The configuration of the system will be driven directly from the ATLAS Run Control System. By using the ATLAS TDAQ Software, a dedicated Micromegas segment has been implemented, in order to include the detector inside the main ATLAS DAQ partition. A full set of tests, on the hardware and software aspects, is presented.

A TCP/IP framework for ethernet-based measurement, control and experiment data distribution

NASA Astrophysics Data System (ADS)

Ocaya, R. O.; Minny, J.

2010-11-01

A complete modular but scalable TCP/IP based scientific instrument control and data distribution system has been designed and realized. The system features an IEEE 802.3 compliant 10 Mbps Medium Access Controller (MAC) and Physical Layer Device that is suitable for the full-duplex monitoring and control of various physically widespread measurement transducers in the presence of a local network infrastructure. The cumbersomeness of exchanging and synchronizing data between the various transducer units using physical storage media led to the choice of TCP/IP as a logical alternative. The system and methods developed are scalable for broader usage over the Internet. The system comprises a PIC18f2620 and ENC28j60 based hardware and a software component written in C, Java/Javascript and Visual Basic.NET programming languages for event-level monitoring and browser user-interfaces respectively. The system exchanges data with the host network through IPv4 packets requested and received on a HTTP page. It also responds to ICMP echo, UDP and ARP requests through a user selectable integrated DHCP and static IPv4 address allocation scheme. The round-trip time, throughput and polling frequency are estimated and reported. A typical application to temperature monitoring and logging is also presented.

Adaptive User Model for Web-Based Learning Environment.

ERIC Educational Resources Information Center

Garofalakis, John; Sirmakessis, Spiros; Sakkopoulos, Evangelos; Tsakalidis, Athanasios

This paper describes the design of an adaptive user model and its implementation in an advanced Web-based Virtual University environment that encompasses combined and synchronized adaptation between educational material and well-known communication facilities. The Virtual University environment has been implemented to support a postgraduate…

Development of sub-100 femtosecond timing and synchronization system

NASA Astrophysics Data System (ADS)

Lin, Zhenyang; Du, Yingchao; Yang, Jin; Xu, Yilun; Yan, Lixin; Huang, Wenhui; Tang, Chuanxiang; Huang, Gang; Du, Qiang; Doolittle, Lawrence; Wilcox, Russell; Byrd, John

2018-01-01

The precise timing and synchronization system is an essential part for the ultra-fast electron and X-ray sources based on the photocathode injector where strict synchronization among RF, laser, and beams are required. In this paper, we present an integrated sub-100 femtosecond timing and synchronization system developed and demonstrated recently in Tsinghua University based on the collaboration with Lawrence Berkeley National Lab. The timing and synchronization system includes the fiber-based CW carrier phase reference distribution system for delivering stabilized RF phase reference to multiple receiver clients, the Low Level RF (LLRF) control system to monitor and generate the phase and amplitude controllable pulse RF signal, and the laser-RF synchronization system for high precision synchronization between optical and RF signals. Each subsystem is characterized by its blocking structure and is also expansible. A novel asymmetric calibration sideband signal method was proposed for eliminating the non-linear distortion in the optical synchronization process. According to offline and online tests, the system can deliver a stable signal to each client and suppress the drift and jitter of the RF signal for the accelerator and the laser oscillator to less than 100 fs RMS (˜0.1° in 2856 MHz frequency). Moreover, a demo system with a LLRF client and a laser-RF synchronization client is deployed and operated successfully at the Tsinghua Thomson scattering X-ray source. The beam-based jitter measurement experiments have been conducted to evaluate the overall performance of the system, and the jitter sources are discussed.

Development of sub-100 femtosecond timing and synchronization system.

PubMed

Lin, Zhenyang; Du, Yingchao; Yang, Jin; Xu, Yilun; Yan, Lixin; Huang, Wenhui; Tang, Chuanxiang; Huang, Gang; Du, Qiang; Doolittle, Lawrence; Wilcox, Russell; Byrd, John

2018-01-01

The precise timing and synchronization system is an essential part for the ultra-fast electron and X-ray sources based on the photocathode injector where strict synchronization among RF, laser, and beams are required. In this paper, we present an integrated sub-100 femtosecond timing and synchronization system developed and demonstrated recently in Tsinghua University based on the collaboration with Lawrence Berkeley National Lab. The timing and synchronization system includes the fiber-based CW carrier phase reference distribution system for delivering stabilized RF phase reference to multiple receiver clients, the Low Level RF (LLRF) control system to monitor and generate the phase and amplitude controllable pulse RF signal, and the laser-RF synchronization system for high precision synchronization between optical and RF signals. Each subsystem is characterized by its blocking structure and is also expansible. A novel asymmetric calibration sideband signal method was proposed for eliminating the non-linear distortion in the optical synchronization process. According to offline and online tests, the system can deliver a stable signal to each client and suppress the drift and jitter of the RF signal for the accelerator and the laser oscillator to less than 100 fs RMS (∼0.1° in 2856 MHz frequency). Moreover, a demo system with a LLRF client and a laser-RF synchronization client is deployed and operated successfully at the Tsinghua Thomson scattering X-ray source. The beam-based jitter measurement experiments have been conducted to evaluate the overall performance of the system, and the jitter sources are discussed.

The scalable implementation of quantum walks using classical light

NASA Astrophysics Data System (ADS)

Goyal, Sandeep K.; Roux, F. S.; Forbes, Andrew; Konrad, Thomas

2014-02-01

A quantum walk is the quantum analog of the classical random walks. Despite their simple structure they form a universal platform to implement any algorithm of quantum computation. However, it is very hard to realize quantum walks with a sufficient number of iterations in quantum systems due to their sensitivity to environmental influences and subsequent loss of coherence. Here we present a scalable implementation scheme for one-dimensional quantum walks for arbitrary number of steps using the orbital angular momentum modes of classical light beams. Furthermore, we show that using the same setup with a minor adjustment we can also realize electric quantum walks.

A universal quantum information processor for scalable quantum communication and networks

PubMed Central

Yang, Xihua; Xue, Bolin; Zhang, Junxiang; Zhu, Shiyao

2014-01-01

Entanglement provides an essential resource for quantum computation, quantum communication, and quantum networks. How to conveniently and efficiently realize the generation, distribution, storage, retrieval, and control of multipartite entanglement is the basic requirement for realistic quantum information processing. Here, we present a theoretical proposal to efficiently and conveniently achieve a universal quantum information processor (QIP) via atomic coherence in an atomic ensemble. The atomic coherence, produced through electromagnetically induced transparency (EIT) in the Λ-type configuration, acts as the QIP and has full functions of quantum beam splitter, quantum frequency converter, quantum entangler, and quantum repeater. By employing EIT-based nondegenerate four-wave mixing processes, the generation, exchange, distribution, and manipulation of light-light, atom-light, and atom-atom multipartite entanglement can be efficiently and flexibly achieved in a deterministic way with only coherent light fields. This method greatly facilitates the operations in quantum information processing, and holds promising applications in realistic scalable quantum communication and quantum networks. PMID:25316514

Scalable quantum computing based on stationary spin qubits in coupled quantum dots inside double-sided optical microcavities

NASA Astrophysics Data System (ADS)

Wei, Hai-Rui; Deng, Fu-Guo

2014-12-01

Quantum logic gates are the key elements in quantum computing. Here we investigate the possibility of achieving a scalable and compact quantum computing based on stationary electron-spin qubits, by using the giant optical circular birefringence induced by quantum-dot spins in double-sided optical microcavities as a result of cavity quantum electrodynamics. We design the compact quantum circuits for implementing universal and deterministic quantum gates for electron-spin systems, including the two-qubit CNOT gate and the three-qubit Toffoli gate. They are compact and economic, and they do not require additional electron-spin qubits. Moreover, our devices have good scalability and are attractive as they both are based on solid-state quantum systems and the qubits are stationary. They are feasible with the current experimental technology, and both high fidelity and high efficiency can be achieved when the ratio of the side leakage to the cavity decay is low.

Scalable quantum computing based on stationary spin qubits in coupled quantum dots inside double-sided optical microcavities.

PubMed

Wei, Hai-Rui; Deng, Fu-Guo

2014-12-18

Quantum logic gates are the key elements in quantum computing. Here we investigate the possibility of achieving a scalable and compact quantum computing based on stationary electron-spin qubits, by using the giant optical circular birefringence induced by quantum-dot spins in double-sided optical microcavities as a result of cavity quantum electrodynamics. We design the compact quantum circuits for implementing universal and deterministic quantum gates for electron-spin systems, including the two-qubit CNOT gate and the three-qubit Toffoli gate. They are compact and economic, and they do not require additional electron-spin qubits. Moreover, our devices have good scalability and are attractive as they both are based on solid-state quantum systems and the qubits are stationary. They are feasible with the current experimental technology, and both high fidelity and high efficiency can be achieved when the ratio of the side leakage to the cavity decay is low.

Special Section on Synchronization in Nonlinear Science and Engineering

NASA Astrophysics Data System (ADS)

Ikeguchi, Tohru; Tokuda, Isao

Synchronization is a ubiquitous phenomenon of coupled nonlinear oscillators, commonly found in physics, engineering, biology, and other diverse disciplines. It has a long research history back to Christiaan Huygens, who discovered synchronized motion of two pendulum clocks in 1673. It is very easy to observe synchronization in our daily life: e.g., metronomes, candle fires, pet-bottle oscillators, saltwater oscillators, and so on(See, for example, experimental movies at http://www.youtube.com/user/IkeguchiLab?feature=watch). For the last few decades, significant development has been made from both theories and experiments on synchronization of coupled limit cycle oscillators as well as coupled chaotic oscillators. Applications have been also developed to communication technologies, controlling techniques, and data analysis. Combined with the idea from complex network theory, neuroscience, and systems biology, the research speed of synchronization has been even accelerated. This Special Section of NOLTA is primarily dedicated to the recent advanced development of basics and applications of synchronization in science and engineering. A number of qualified works is included, ranging from experimental study on synchronization of Huygens' system, analog circuits, and singing voice to applied study of synchronization in communication networks. One invited paper is devoted to comprehensive reviews on generalized synchronization of chaotic oscillators. On behalf of the editorial committee of the special section, the guest editors would like to express their sincere thanks to all the authors for their excellent contributions. In particular, they are grateful to Prof. Dr. Ulrich Parlitz for contributing his distinguished review article. They would also like to thank the reviewers and the members of the guest editorial committee, especially Prof. Hiroo Sekiya of Chiba University and the editorial staffs of the NOLTA journal, for their supports on publishing this Special Section.

Stability Assessment of a System Comprising a Single Machine and Inverter with Scalable Ratings

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

Johnson, Brian B; Lin, Yashen; Gevorgian, Vahan

From the inception of power systems, synchronous machines have acted as the foundation of large-scale electrical infrastructures and their physical properties have formed the cornerstone of system operations. However, power electronics interfaces are playing a growing role as they are the primary interface for several types of renewable energy sources and storage technologies. As the role of power electronics in systems continues to grow, it is crucial to investigate the properties of bulk power systems in low inertia settings. In this paper, we assess the properties of coupled machine-inverter systems by studying an elementary system comprised of a synchronous generator,more » three-phase inverter, and a load. Furthermore, the inverter model is formulated such that its power rating can be scaled continuously across power levels while preserving its closed-loop response. Accordingly, the properties of the machine-inverter system can be assessed for varying ratios of machine-to-inverter power ratings and, hence, differing levels of inertia. After linearizing the model and assessing its eigenvalues, we show that system stability is highly dependent on the interaction between the inverter current controller and machine exciter, thus uncovering a key concern with mixed machine-inverter systems and motivating the need for next-generation grid-stabilizing inverter controls.« less

Reducing Distance through Distance Learning: The Community College Leadership Doctoral Program at Colorado State University.

ERIC Educational Resources Information Center

Davies, Timothy Gray; Quick, Don

2001-01-01

Reports that the Community College Leadership program at Colorado State University creates a community among its nontraditional doctoral students using a blend of different learning modalities, including face-to-face experiences and synchronous and asynchronous online discussions. Discusses three types of support necessary for distance learning…

UpSetR: an R package for the visualization of intersecting sets and their properties.

PubMed

Conway, Jake R; Lex, Alexander; Gehlenborg, Nils

2017-09-15

Venn and Euler diagrams are a popular yet inadequate solution for quantitative visualization of set intersections. A scalable alternative to Venn and Euler diagrams for visualizing intersecting sets and their properties is needed. We developed UpSetR, an open source R package that employs a scalable matrix-based visualization to show intersections of sets, their size, and other properties. UpSetR is available at https://github.com/hms-dbmi/UpSetR/ and released under the MIT License. A Shiny app is available at https://gehlenborglab.shinyapps.io/upsetr/ . nils@hms.harvard.edu. Supplementary data are available at Bioinformatics online. © The Author(s) 2017. Published by Oxford University Press.

NLP-PIER: A Scalable Natural Language Processing, Indexing, and Searching Architecture for Clinical Notes.

PubMed

McEwan, Reed; Melton, Genevieve B; Knoll, Benjamin C; Wang, Yan; Hultman, Gretchen; Dale, Justin L; Meyer, Tim; Pakhomov, Serguei V

2016-01-01

Many design considerations must be addressed in order to provide researchers with full text and semantic search of unstructured healthcare data such as clinical notes and reports. Institutions looking at providing this functionality must also address the big data aspects of their unstructured corpora. Because these systems are complex and demand a non-trivial investment, there is an incentive to make the system capable of servicing future needs as well, further complicating the design. We present architectural best practices as lessons learned in the design and implementation NLP-PIER (Patient Information Extraction for Research), a scalable, extensible, and secure system for processing, indexing, and searching clinical notes at the University of Minnesota.

Adaptive Synchronization of Fractional Order Complex-Variable Dynamical Networks via Pinning Control

NASA Astrophysics Data System (ADS)

Ding, Da-Wei; Yan, Jie; Wang, Nian; Liang, Dong

2017-09-01

In this paper, the synchronization of fractional order complex-variable dynamical networks is studied using an adaptive pinning control strategy based on close center degree. Some effective criteria for global synchronization of fractional order complex-variable dynamical networks are derived based on the Lyapunov stability theory. From the theoretical analysis, one concludes that under appropriate conditions, the complex-variable dynamical networks can realize the global synchronization by using the proper adaptive pinning control method. Meanwhile, we succeed in solving the problem about how much coupling strength should be applied to ensure the synchronization of the fractional order complex networks. Therefore, compared with the existing results, the synchronization method in this paper is more general and convenient. This result extends the synchronization condition of the real-variable dynamical networks to the complex-valued field, which makes our research more practical. Finally, two simulation examples show that the derived theoretical results are valid and the proposed adaptive pinning method is effective. Supported by National Natural Science Foundation of China under Grant No. 61201227, National Natural Science Foundation of China Guangdong Joint Fund under Grant No. U1201255, the Natural Science Foundation of Anhui Province under Grant No. 1208085MF93, 211 Innovation Team of Anhui University under Grant Nos. KJTD007A and KJTD001B, and also supported by Chinese Scholarship Council

Semiannual Report, October 1, 1989 through March 31, 1990 (Institute for Computer Applications in Science and Engineering)

DTIC Science & Technology

1990-06-01

synchronization . We consider the performance of various synchronization protocols by deriving upper and lower bounds on optimal perfor- mance, upper bounds on Time ...from universities and from industry, who have resident appointments for limited periods of time , and by consultants. Members of NASA’s research staff...convergence to steady state is also being studied together with D. Gottlieb. The idea is to generalize the concept of local- time stepping by minimizing the

The investigation of bandwidth efficient coding and modulation techniques

NASA Technical Reports Server (NTRS)

1992-01-01

The New Mexico State University Center for Space Telemetering and Telecommunications systems has been, and is currently, engaged in the investigation of trellis-coded modulation (TCM) communication systems. In particular, TCM utilizing M-ary phase shift keying is being studied. The study of carrier synchronization in a TCM environment, or in MPSK systems in general, has been one of the two main thrusts of this grant. This study has involved both theoretical modelling and software simulation of the carrier synchronization problem.

In vitro cardiomyocyte-driven biogenerator based on aligned piezoelectric nanofibers

NASA Astrophysics Data System (ADS)

Liu, Xia; Zhao, Hui; Lu, Yingxian; Li, Song; Lin, Liwei; Du, Yanan; Wang, Xiaohong

2016-03-01

Capturing the body's mechanical energy from the heart, lungs, and diaphragm can probably meet the requirements for in vivo applications of implantable biomedical devices. In this work, we present a novel contractile cardiomyocyte (CM)-driven biogenerator based on piezoelectric nanofibers (NFs) uniaxially aligned on a PDMS thin film. Flexible nanostructures interact with the CMs, as a physical cue to guide the CMs to align in a specific way, and create mechanical interfaces of contractile CMs and piezoelectric NFs. As such, the cellular construct features specific alignment and synchronous contraction, which realizes the maximal resultant force to drive the NFs to bend periodically. Studies on contraction mapping show that neonatal rat CMs self-assemble into a functional bio-bot film with well-defined axes of force generation. Consequently, the biogenerator produces an average voltage of 200 mV and current of 45 nA at the cell concentration of 1.0 million per ml, offering a biocompatible and scalable platform for biological energy conversion.Capturing the body's mechanical energy from the heart, lungs, and diaphragm can probably meet the requirements for in vivo applications of implantable biomedical devices. In this work, we present a novel contractile cardiomyocyte (CM)-driven biogenerator based on piezoelectric nanofibers (NFs) uniaxially aligned on a PDMS thin film. Flexible nanostructures interact with the CMs, as a physical cue to guide the CMs to align in a specific way, and create mechanical interfaces of contractile CMs and piezoelectric NFs. As such, the cellular construct features specific alignment and synchronous contraction, which realizes the maximal resultant force to drive the NFs to bend periodically. Studies on contraction mapping show that neonatal rat CMs self-assemble into a functional bio-bot film with well-defined axes of force generation. Consequently, the biogenerator produces an average voltage of 200 mV and current of 45 nA at the cell concentration of 1.0 million per ml, offering a biocompatible and scalable platform for biological energy conversion. Electronic supplementary information (ESI) available: Includes the ESI methods and figures, and videos of cell contraction and biogenerator bending. See DOI: 10.1039/c5nr08430j

Universal Parameter Measurement and Sensorless Vector Control of Induction and Permanent Magnet Synchronous Motors

NASA Astrophysics Data System (ADS)

Yamamoto, Shu; Ara, Takahiro

Recently, induction motors (IMs) and permanent-magnet synchronous motors (PMSMs) have been used in various industrial drive systems. The features of the hardware device used for controlling the adjustable-speed drive in these motors are almost identical. Despite this, different techniques are generally used for parameter measurement and speed-sensorless control of these motors. If the same technique can be used for parameter measurement and sensorless control, a highly versatile adjustable-speed-drive system can be realized. In this paper, the authors describe a new universal sensorless control technique for both IMs and PMSMs (including salient pole and nonsalient pole machines). A mathematical model applicable for IMs and PMSMs is discussed. Using this model, the authors derive the proposed universal sensorless vector control algorithm on the basis of estimation of the stator flux linkage vector. All the electrical motor parameters are determined by a unified test procedure. The proposed method is implemented on three test machines. The actual driving test results demonstrate the validity of the proposed method.

Communication Strategies in a Telecollaboration Project with a Focus on Latin American History

ERIC Educational Resources Information Center

Fernández, Susana S.

2016-01-01

This paper will present and discuss the linguistic challenges that Argentinian university students of history and Danish university students of Spanish met during the course of a telecollaboration project based on synchronous communication in Skype. The purpose of this discussion is to identify linguistic pitfalls and the solutions adopted by both…

Cross-scale efficient tensor contractions for coupled cluster computations through multiple programming model backends

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

Ibrahim, Khaled Z.; Epifanovsky, Evgeny; Williams, Samuel

Coupled-cluster methods provide highly accurate models of molecular structure through explicit numerical calculation of tensors representing the correlation between electrons. These calculations are dominated by a sequence of tensor contractions, motivating the development of numerical libraries for such operations. While based on matrix–matrix multiplication, these libraries are specialized to exploit symmetries in the molecular structure and in electronic interactions, and thus reduce the size of the tensor representation and the complexity of contractions. The resulting algorithms are irregular and their parallelization has been previously achieved via the use of dynamic scheduling or specialized data decompositions. We introduce our efforts tomore » extend the Libtensor framework to work in the distributed memory environment in a scalable and energy-efficient manner. We achieve up to 240× speedup compared with the optimized shared memory implementation of Libtensor. We attain scalability to hundreds of thousands of compute cores on three distributed-memory architectures (Cray XC30 and XC40, and IBM Blue Gene/Q), and on a heterogeneous GPU-CPU system (Cray XK7). As the bottlenecks shift from being compute-bound DGEMM's to communication-bound collectives as the size of the molecular system scales, we adopt two radically different parallelization approaches for handling load-imbalance, tasking and bulk synchronous models. Nevertheless, we preserve a unified interface to both programming models to maintain the productivity of computational quantum chemists.« less

Scalable Photogrammetric Motion Capture System "mosca": Development and Application

NASA Astrophysics Data System (ADS)

Knyaz, V. A.

2015-05-01

Wide variety of applications (from industrial to entertainment) has a need for reliable and accurate 3D information about motion of an object and its parts. Very often the process of movement is rather fast as in cases of vehicle movement, sport biomechanics, animation of cartoon characters. Motion capture systems based on different physical principles are used for these purposes. The great potential for obtaining high accuracy and high degree of automation has vision-based system due to progress in image processing and analysis. Scalable inexpensive motion capture system is developed as a convenient and flexible tool for solving various tasks requiring 3D motion analysis. It is based on photogrammetric techniques of 3D measurements and provides high speed image acquisition, high accuracy of 3D measurements and highly automated processing of captured data. Depending on the application the system can be easily modified for different working areas from 100 mm to 10 m. The developed motion capture system uses from 2 to 4 technical vision cameras for video sequences of object motion acquisition. All cameras work in synchronization mode at frame rate up to 100 frames per second under the control of personal computer providing the possibility for accurate calculation of 3D coordinates of interest points. The system was used for a set of different applications fields and demonstrated high accuracy and high level of automation.

Cross-scale efficient tensor contractions for coupled cluster computations through multiple programming model backends

DOE PAGES

Ibrahim, Khaled Z.; Epifanovsky, Evgeny; Williams, Samuel; ...

2017-03-08

Coupled-cluster methods provide highly accurate models of molecular structure through explicit numerical calculation of tensors representing the correlation between electrons. These calculations are dominated by a sequence of tensor contractions, motivating the development of numerical libraries for such operations. While based on matrix–matrix multiplication, these libraries are specialized to exploit symmetries in the molecular structure and in electronic interactions, and thus reduce the size of the tensor representation and the complexity of contractions. The resulting algorithms are irregular and their parallelization has been previously achieved via the use of dynamic scheduling or specialized data decompositions. We introduce our efforts tomore » extend the Libtensor framework to work in the distributed memory environment in a scalable and energy-efficient manner. We achieve up to 240× speedup compared with the optimized shared memory implementation of Libtensor. We attain scalability to hundreds of thousands of compute cores on three distributed-memory architectures (Cray XC30 and XC40, and IBM Blue Gene/Q), and on a heterogeneous GPU-CPU system (Cray XK7). As the bottlenecks shift from being compute-bound DGEMM's to communication-bound collectives as the size of the molecular system scales, we adopt two radically different parallelization approaches for handling load-imbalance, tasking and bulk synchronous models. Nevertheless, we preserve a unified interface to both programming models to maintain the productivity of computational quantum chemists.« less

A System for Distributing Real-Time Customized (NEXRAD-Radar) Geosciences Data

NASA Astrophysics Data System (ADS)

Singh, Satpreet; McWhirter, Jeff; Krajewski, Witold; Kruger, Anton; Goska, Radoslaw; Seo, Bongchul; Domaszczynski, Piotr; Weber, Jeff

2010-05-01

Hydrometeorologists and hydrologists can benefit from (weather) radar derived rain products, including rain rates and accumulations. The Hydro-NEXRAD system (HNX1) has been in operation since 2006 at IIHR-Hydroscience and Engineering at The University of Iowa. It provides rapid and user-friendly access to such user-customized products, generated using archived Weather Surveillance Doppler Radar (WSR-88D) data from the NEXRAD weather radar network in the United States. HNX1 allows researchers to deal directly with radar-derived rain products, without the burden of the details of radar data collection, quality control, processing, and format conversion. A number of hydrologic applications can benefit from a continuous real-time feed of customized radar-derived rain products. We are currently developing such a system, Hydro-NEXRAD 2 (HNX2). HNX2 collects real-time, unprocessed data from multiple NEXRAD radars as they become available, processes them through a user-configurable pipeline of data-processing modules, and then publishes processed products at regular intervals. Modules in the data processing pipeline encapsulate algorithms such as non-meteorological echo detection, range correction, radar-reflectivity-rain rate (Z-R) conversion, advection correction, merging products from multiple radars, and grid transformations. HNX2's implementation presents significant challenges, including quality-control, error-handling, time-synchronization of data from multiple asynchronous sources, generation of multiple-radar metadata products, distribution of products to a user base with diverse needs and constraints, and scalability. For content management and distribution, HNX2 uses RAMADDA (Repository for Archiving, Managing and Accessing Diverse Data), developed by the UCAR/Unidata Program Center in the Unites States. RAMADDA allows HNX2 to publish products through automation and gives users multiple access methods to the published products, including simple web-browser based access, and OpenDAP access. The latter allows a user to set up automation at his/her end, and fetch new data from HNX2 at regular intervals. HNX2 uses a two-dimensional metadata structure called a mosaic for managing metadata of the rain products. Currently, HNX2 is in pre-production state and is serving near real-time rain-rate map data-products for individual radars and merged data-products from seven radars covering the state of Iowa in the United States. These products then drive a rainfall-runoff model called CUENCAS, which is used as part of the Iowa Flood Center (housed at The University of Iowa) real-time flood forecasting system. We are currently developing a generalized scalable framework that will run on inexpensive hardware and will provide products for basins anywhere in the continental United States.

Center of Cancer Nanotechnology Excellence for Translational Diagnostics

Cancer.gov

The Center of Cancer Nanotechnology Excellence for Translational Diagnostics, which forms the third cycle CCNE Program at Stanford University, is a consortium that has three highly synchronized Projects and three Cores.

GEECS (Generalized Equipment and Experiment Control System)

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

GONSALVES, ANTHONY; DESHMUKH, AALHAD

2017-01-12

GEECS (Generalized Equipment and Experiment Control System) monitors and controls equipment distributed across a network, performs experiments by scanning input variables, and collects and stores various types of data synchronously from devices. Examples of devices include cameras, motors and pressure gauges. GEEKS is based upon LabView graphical object oriented programming (GOOP), allowing for a modular and scalable framework. Data is published for subscription of an arbitrary number of variables over TCP. A secondary framework allows easy development of graphical user interfaces for a combined control of any available devices on the control system without the need of programming knowledge. Thismore » allows for rapid integration of GEECS into a wide variety of systems. A database interface provides for devise and process configuration while allowing the user to save large quantities of data to local or network drives.« less

Towards scalable Byzantine fault-tolerant replication

NASA Astrophysics Data System (ADS)

Zbierski, Maciej

2017-08-01

Byzantine fault-tolerant (BFT) replication is a powerful technique, enabling distributed systems to remain available and correct even in the presence of arbitrary faults. Unfortunately, existing BFT replication protocols are mostly load-unscalable, i.e. they fail to respond with adequate performance increase whenever new computational resources are introduced into the system. This article proposes a universal architecture facilitating the creation of load-scalable distributed services based on BFT replication. The suggested approach exploits parallel request processing to fully utilize the available resources, and uses a load balancer module to dynamically adapt to the properties of the observed client workload. The article additionally provides a discussion on selected deployment scenarios, and explains how the proposed architecture could be used to increase the dependability of contemporary large-scale distributed systems.

NLP-PIER: A Scalable Natural Language Processing, Indexing, and Searching Architecture for Clinical Notes

PubMed Central

McEwan, Reed; Melton, Genevieve B.; Knoll, Benjamin C.; Wang, Yan; Hultman, Gretchen; Dale, Justin L.; Meyer, Tim; Pakhomov, Serguei V.

2016-01-01

Many design considerations must be addressed in order to provide researchers with full text and semantic search of unstructured healthcare data such as clinical notes and reports. Institutions looking at providing this functionality must also address the big data aspects of their unstructured corpora. Because these systems are complex and demand a non-trivial investment, there is an incentive to make the system capable of servicing future needs as well, further complicating the design. We present architectural best practices as lessons learned in the design and implementation NLP-PIER (Patient Information Extraction for Research), a scalable, extensible, and secure system for processing, indexing, and searching clinical notes at the University of Minnesota. PMID:27570663

AgShare Open Knowledge: Improving Rural Communities through University Student Action Research

ERIC Educational Resources Information Center

Geith, Christine; Vignare, Karen

2013-01-01

The aim of AgShare is to create a scalable and sustainable collaboration of existing organizations for African publishing, localizing, and sharing of science-based teaching and learning materials that fill critical resource gaps in African MSc agriculture curriculum. Shared innovative practices are emerging through the AgShare projects, not only…

Taking over Someone Else's E-Learning Design: Challenges Trigger Change in E-Learning Beliefs and Practices

ERIC Educational Resources Information Center

Scott, Karen M.

2014-01-01

As universities invest in the development of e-learning resources, e-learning sustainability has come under consideration. This has largely focused on the challenges and facilitators of organisational and technological sustainability and scalability, and professional development. Little research has examined the experience of a teacher dealing…

Evaluation of Scalable Applications of Information Technology to On-Campus Learning.

ERIC Educational Resources Information Center

Matthews, Harry R.; Sommer, Barbara; Maher, Michael; Acredolo, Curt; Ho, Arnold; Falk, Richard

The University of California, Davis, is transforming large general education courses in a cost-effective way that maintains high academic standards in the face of rising student enrollments. Two multi-year pilot projects have demonstrated the feasibility of using rich online learning environments to reduce the dependence on formal lectures. This…

NREL Announces Third Round of Start-Ups to Participate in the Wells Fargo

Science.gov Websites

innovative commercial building technologies Photo of NREL researchers talking. George Lee and Steven Low that provide scalable solutions to reduce the energy impact of commercial buildings. Including Round 3 kit for commercial buildings. Referred to apply to program by University of Colorado Boulder Software

Scalable Emergency Response System for Oceangoing Assets Report on Brainstorming Concept Evaluations

DTIC Science & Technology

2007-04-11

Andr´e Badertscher, Andr´e Guignard, and Auke Jan Ijspeert, Swimming and Crawling with an Amphibious Snake Robot. 4. Alexander S. Boxerbaum, Philip ... Kotler , Mindy & Hillman, Ian “Japanese Nuclear Energy Policy and Public Opinion” James A Baker III Institute for Public Policy Rice University May 2000

Teaching and Student Success: ACUE Makes the Link

ERIC Educational Resources Information Center

Mangum, Elmira

2017-01-01

In late 2014, higher education leaders and experts in pedagogy were convened by the Association of College and University Educators (ACUE) to develop a scalable and comprehensive program on the essentials of college teaching. The result is ACUE's Course in Effective Teaching Practices in which faculty learn about and implement evidence-based…

Fixed-Time Outer Synchronization of Complex Networks with Noise Coupling

NASA Astrophysics Data System (ADS)

Shi, Hong-Jun; Miao, Lian-Ying; Sun, Yong-Zheng; Liu, Mao-Xing

2018-03-01

In this paper, the fixed-time outer synchronization of complex networks with noise coupling is investigated. Based on the theory of fixed-time stability and matrix inequalities, sufficient conditions for fixed-time outer synchronization are established and the estimation of the upper bound of the setting time is obtained. The result shows that the setting time can be adjusted to a desired value regardless of the initial states. Numerical simulations are performed to verify the effectiveness of the theoretical results. The effects of control parameters and the density of controlled nodes on the converging time are studied. Supported by the National Natural Science Foundation of China under Grant Nos. 11711530203 and 11771443, and the Fundamental Research Funds for the Central Universities under Grant No. 2015XKMS076

Driving Sodium-Potassium Pumps With An Oscillating Electric Field: Effects On Muscle Recovery In The Human Biceps Brachii

NASA Astrophysics Data System (ADS)

Bovyn, Matt; Chen, Wei; Lanes, Olivia; Mast, Jason

2013-03-01

Dr. Chen has developed a technique called synchronization modulation, which uses an oscillating electric field to increase the rate at which the sodium-potassium pumps in the cell membrane work. Because the sodium-potassium pump is integral in the recovery of skeletal muscle fibers after an action potential, we investigated the effects of applying synchronization modulation to muscles which had already undergone fatigue due to repeated action potentials during exercise. Fatigue was induced in human subjects' biceps brachii through isometric contraction. Surface electromyography measurements of fatigue index were used to quantify how the muscle recovered over the minutes following fatigue, both when synchronization modulation was applied and when it was absent. The preliminary results were inconclusive, but it is hoped that in later work it will be shown that applying synchronization modulation is effective in increasing the rate at which the muscle recovers to its initial state. This would demonstrate not only that synchronization modulation can be successfully applied to human muscle, but also that it has many potential applications in sports medicine and novel disease treatments. Work done as part of an REU program at the University of South Florida

Secure transport and adaptation of MC-EZBC video utilizing H.264-based transport protocols☆

PubMed Central

Hellwagner, Hermann; Hofbauer, Heinz; Kuschnig, Robert; Stütz, Thomas; Uhl, Andreas

2012-01-01

Universal Multimedia Access (UMA) calls for solutions where content is created once and subsequently adapted to given requirements. With regard to UMA and scalability, which is required often due to a wide variety of end clients, the best suited codecs are wavelet based (like the MC-EZBC) due to their inherent high number of scaling options. However, most transport technologies for delivering videos to end clients are targeted toward the H.264/AVC standard or, if scalability is required, the H.264/SVC. In this paper we will introduce a mapping of the MC-EZBC bitstream to existing H.264/SVC based streaming and scaling protocols. This enables the use of highly scalable wavelet based codecs on the one hand and the utilization of already existing network technologies without accruing high implementation costs on the other hand. Furthermore, we will evaluate different scaling options in order to choose the best option for given requirements. Additionally, we will evaluate different encryption options based on transport and bitstream encryption for use cases where digital rights management is required. PMID:26869746

[ANTHROPOMETRIC PROPORTIONALITY METHOD ELECTION IN A SPORT POPULATION; COMPARISON OF THREE METHODS].

PubMed

Almagià, Atilio; Araneda, Alberto; Sánchez, Javier; Sánchez, Patricio; Zúñiga, Maximiliano; Plaza, Paula

2015-09-01

the proportionality model application, based on ideal proportions, would have a great impact on high performance sports, due to best athletes to resemble anthropometrically. the objective of this study was to compare the following anthropometric methods of proportionality: Phantom, Combined and Scalable, in male champion university Chilean soccer players in 2012 and 2013, using South American professional soccer players as criterion, in order to find the most appropriate proportionality method to sports populations. the measerement of 22 kinanthropometric variables was performed, according to the ISAK protocol, to a sample constituted of 13 members of the men's soccer team of the Pontificia Universidad Católica de Valparaíso. The Z-values of the anthropometrics variables of each method were obtained using their respective equations. It was used as criterion population South American soccer players. a similar trend was observed between the three methods. Significant differences (p < 0.05) were found in some Z-values of Scalable and Combined methods compared to Phantom method. No significant differences were observed between the results obtained by the Combined and Scalable methods, except in wrist, thigh and hip perimeters. it is more appropriate to use the Scalable method over the Combined and Phantom methods for the comparison of Z values in kinanthropometric variables in athletes of the same discipline. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

From globally coupled maps to complex-systems biology

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

Kaneko, Kunihiko, E-mail: kaneko@complex.c.u-tokyo.ac.jp

Studies of globally coupled maps, introduced as a network of chaotic dynamics, are briefly reviewed with an emphasis on novel concepts therein, which are universal in high-dimensional dynamical systems. They include clustering of synchronized oscillations, hierarchical clustering, chimera of synchronization and desynchronization, partition complexity, prevalence of Milnor attractors, chaotic itinerancy, and collective chaos. The degrees of freedom necessary for high dimensionality are proposed to equal the number in which the combinatorial exceeds the exponential. Future analysis of high-dimensional dynamical systems with regard to complex-systems biology is briefly discussed.

Injection locking of optomechanical oscillators via acoustic waves

NASA Astrophysics Data System (ADS)

Huang, Ke; Hossein-Zadeh, Mani

2018-04-01

Injection locking is a powerful technique for synchronization of oscillator networks and controlling the phase and frequency of individual oscillators using similar or other types of oscillators. Here, we present the first demonstration of injection locking of a radiation-pressure driven optomechanical oscillator (OMO) via acoustic waves. As opposed to previously reported techniques (based on pump modulation or direct application of a modulated electrostatic force), injection locking of OMO via acoustic waves does not require optical power modulation or physical contact with the OMO and it can easily be implemented on various platforms. Using this approach we have locked the phase and frequency of two distinct modes of a microtoroidal silica OMO to a piezoelectric transducer (PZT). We have characterized the behavior of the injection locked OMO with three acoustic excitation configurations and showed that even without proper acoustic impedance matching the OMO can be locked to the PZT and tuned over 17 kHz with only -30 dBm of RF power fed to the PZT. The high efficiency, simplicity and scalability of the proposed approach paves the road toward a new class of photonic systems that rely on synchronization of several OMOs to a single or multiple RF oscillators with applications in optical communication, metrology and sensing. Beyond its practical applications, injection locking via acoustic waves can be used in fundamental studies in quantum optomechanics where thermal and optical isolation of the OMO are critical.

Cohesion and Joint Speech: Right Hemisphere Contributions to Synchronized Vocal Production

PubMed Central

Jasmin, Kyle M.; McGettigan, Carolyn; Agnew, Zarinah K.; Lavan, Nadine; Josephs, Oliver; Cummins, Fred

2016-01-01

Synchronized behavior (chanting, singing, praying, dancing) is found in all human cultures and is central to religious, military, and political activities, which require people to act collaboratively and cohesively; however, we know little about the neural underpinnings of many kinds of synchronous behavior (e.g., vocal behavior) or its role in establishing and maintaining group cohesion. In the present study, we measured neural activity using fMRI while participants spoke simultaneously with another person. We manipulated whether the couple spoke the same sentence (allowing synchrony) or different sentences (preventing synchrony), and also whether the voice the participant heard was “live” (allowing rich reciprocal interaction) or prerecorded (with no such mutual influence). Synchronous speech was associated with increased activity in posterior and anterior auditory fields. When, and only when, participants spoke with a partner who was both synchronous and “live,” we observed a lack of the suppression of auditory cortex, which is commonly seen as a neural correlate of speech production. Instead, auditory cortex responded as though it were processing another talker's speech. Our results suggest that detecting synchrony leads to a change in the perceptual consequences of one's own actions: they are processed as though they were other-, rather than self-produced. This may contribute to our understanding of synchronized behavior as a group-bonding tool. SIGNIFICANCE STATEMENT Synchronized human behavior, such as chanting, dancing, and singing, are cultural universals with functional significance: these activities increase group cohesion and cause participants to like each other and behave more prosocially toward each other. Here we use fMRI brain imaging to investigate the neural basis of one common form of cohesive synchronized behavior: joint speaking (e.g., the synchronous speech seen in chants, prayers, pledges). Results showed that joint speech recruits additional right hemisphere regions outside the classic speech production network. Additionally, we found that a neural marker of self-produced speech, suppression of sensory cortices, did not occur during joint synchronized speech, suggesting that joint synchronized behavior may alter self-other distinctions in sensory processing. PMID:27122026

Cohesion and Joint Speech: Right Hemisphere Contributions to Synchronized Vocal Production.

PubMed

Jasmin, Kyle M; McGettigan, Carolyn; Agnew, Zarinah K; Lavan, Nadine; Josephs, Oliver; Cummins, Fred; Scott, Sophie K

2016-04-27

Synchronized behavior (chanting, singing, praying, dancing) is found in all human cultures and is central to religious, military, and political activities, which require people to act collaboratively and cohesively; however, we know little about the neural underpinnings of many kinds of synchronous behavior (e.g., vocal behavior) or its role in establishing and maintaining group cohesion. In the present study, we measured neural activity using fMRI while participants spoke simultaneously with another person. We manipulated whether the couple spoke the same sentence (allowing synchrony) or different sentences (preventing synchrony), and also whether the voice the participant heard was "live" (allowing rich reciprocal interaction) or prerecorded (with no such mutual influence). Synchronous speech was associated with increased activity in posterior and anterior auditory fields. When, and only when, participants spoke with a partner who was both synchronous and "live," we observed a lack of the suppression of auditory cortex, which is commonly seen as a neural correlate of speech production. Instead, auditory cortex responded as though it were processing another talker's speech. Our results suggest that detecting synchrony leads to a change in the perceptual consequences of one's own actions: they are processed as though they were other-, rather than self-produced. This may contribute to our understanding of synchronized behavior as a group-bonding tool. Synchronized human behavior, such as chanting, dancing, and singing, are cultural universals with functional significance: these activities increase group cohesion and cause participants to like each other and behave more prosocially toward each other. Here we use fMRI brain imaging to investigate the neural basis of one common form of cohesive synchronized behavior: joint speaking (e.g., the synchronous speech seen in chants, prayers, pledges). Results showed that joint speech recruits additional right hemisphere regions outside the classic speech production network. Additionally, we found that a neural marker of self-produced speech, suppression of sensory cortices, did not occur during joint synchronized speech, suggesting that joint synchronized behavior may alter self-other distinctions in sensory processing. Copyright © 2016 Jasmin et al.

Synchronous distance interactive classroom conferencing.

PubMed

Oz, Halit Hami

2005-01-01

New medical schools have been opened in the eastern and southeastern regions of the country. They are also in great need of basic medical science teachers. However, due to security reasons over the past two decades, teachers from the established universities do not desire to travel to these medical schools for lectures. The objective of this study was to develop a synchronous classroom conferencing system to teach basic science courses between two general purpose technology enhanced classrooms of two different universities--Istanbul University (IU) and Istanbul and Harran University (HU), Urfa--located 1,500 miles apart in Turkey. I videostreamed the instructor, content from document camera, Power Point presentations at IU, and the students at both places, IU and HU. In addition, I synchronously broadcast two whiteboards by attaching two mimio devices to the two blackboards in the IU classroom to capture and convert everything written or drawn on them into broadcasting over the intranet. This technique is called "boardcasting," which allows users to stream ink and audio together over the Internet or intranet live. A total of 260 students at IU and 150 students at HU were involved. Off-campus HU students also have asynchronous access to the stored lecture video materials at any time. Midterm and final examinations were administered simultaneously using the same questions at both sites in two universities under the observation of the teaching faculty using the very same system. This system permitted interaction between the students in the class at IU and remote-campus students at HU and the instructor in real time. The instructors at IU were able to maintain a significant level of spontaneity in using their multimedia materials and electronic whiteboards. The mean midterm and final exam scores of students at both universities were similar. The system developed in this study can be used by the medical faculty at the main teaching hospitals to deliver their lectures in real time to the medical students when they are on placement in general practices, ambulatory clinics, and district hospitals in rural areas or to the students of other medical schools. This is an efficacious system in developing countries where availability of high-speed networks and cost of communication are major concerns.

Inter-subject synchronization of brain responses during natural music listening

PubMed Central

Abrams, Daniel A.; Ryali, Srikanth; Chen, Tianwen; Chordia, Parag; Khouzam, Amirah; Levitin, Daniel J.; Menon, Vinod

2015-01-01

Music is a cultural universal and a rich part of the human experience. However, little is known about common brain systems that support the processing and integration of extended, naturalistic ‘real-world’ music stimuli. We examined this question by presenting extended excerpts of symphonic music, and two pseudomusical stimuli in which the temporal and spectral structure of the Natural Music condition were disrupted, to non-musician participants undergoing functional brain imaging and analysing synchronized spatiotemporal activity patterns between listeners. We found that music synchronizes brain responses across listeners in bilateral auditory midbrain and thalamus, primary auditory and auditory association cortex, right-lateralized structures in frontal and parietal cortex, and motor planning regions of the brain. These effects were greater for natural music compared to the pseudo-musical control conditions. Remarkably, inter-subject synchronization in the inferior colliculus and medial geniculate nucleus was also greater for the natural music condition, indicating that synchronization at these early stages of auditory processing is not simply driven by spectro-temporal features of the stimulus. Increased synchronization during music listening was also evident in a right-hemisphere fronto-parietal attention network and bilateral cortical regions involved in motor planning. While these brain structures have previously been implicated in various aspects of musical processing, our results are the first to show that these regions track structural elements of a musical stimulus over extended time periods lasting minutes. Our results show that a hierarchical distributed network is synchronized between individuals during the processing of extended musical sequences, and provide new insight into the temporal integration of complex and biologically salient auditory sequences. PMID:23578016

Incidence and risk factors of synchronous colorectal cancer in patients with esophageal cancer: an analysis of 480 consecutive colonoscopies before surgery.

PubMed

Yoshida, Naoya; Tamaoki, Yuka; Baba, Yoshifumi; Sakamoto, Yasuo; Miyamoto, Yuji; Iwatsuki, Masaaki; Shono, Takashi; Miyamoto, Hideaki; Imuta, Masanori; Kurashige, Junji; Sawayama, Hiroshi; Tokunaga, Ryuma; Watanabe, Masayuki; Sasaki, Yutaka; Yamashita, Yasuyuki; Baba, Hideo

2016-12-01

The precise incidence rates of multiple primary colorectal cancers in esophageal cancer patients are unknown. In total, 480 consecutive patients with esophageal cancers surgically resected in the Kumamoto University Hospital received preoperative total colonoscopy for the assessment of colorectal disease between April 2005 and February 2016. We retrospectively investigated the occurrence of synchronous colorectal cancer with esophageal cancer. In addition, we examined the risk factors for the incidence of multiple primary colorectal cancers. Of the 480 patients, 14 (2.9 %) had synchronous colorectal cancers, 13 had well-differentiated tubular adenocarcinomas, and 1 had papillary adenocarcinoma. Other 14 patients had metachronous colorectal cancer. The current incidence rates of synchronous and total (both synchronous and metachronous) colorectal cancers outnumbered those in normal healthy population and those in esophageal cancer patients which previously reported by The Japan Esophageal Society. The age ≥70 years (hazard ratio 4.82, 95 % confidence interval 1.473-15.78; p = 0.009) and Brinkman index ≥800 (hazard ratio 3.47, 95 % confidence interval 1.056-11.37; p = 0.040) were the independent risk factors for the incidence of synchronous colorectal cancer. They were also the independent risk factors for the incidence of total colorectal cancer. The results of the present study suggested that pretreatment screening with total colonoscopy is meaningful for patients with esophageal cancer, because the frequency of synchronous colorectal cancer was not negligible. Particularly, in patients >70 years and with history of heavy smoking, pretreatment colonoscopy might be necessary.

Library Instruction for First Year Students Using a CMS Meta-Course: Scalable and Customizable!

ERIC Educational Resources Information Center

Johnson, Megan

2017-01-01

This case study reports on the process for creating a self-paced non-credit information literacy (IL) course delivered via a university's course management system. The four online modules are designed to contextualize information literacy competencies within the curriculum taught in First Year Seminar (FYS) courses. The meta-course approach…

Understanding Similarities and Differences between Parents' and Teachers' Construal of Children's Behaviour

ERIC Educational Resources Information Center

Winterbottom, Mark; Smith, Sarah; Hind, Sally; Haggard, Mark

2008-01-01

Purpose: eduroam[TM] has already been proved to be a scalable, secure and feasible way for universities and research institutions to connect their wireless networks into a WLAN roaming community, but the advantages of eduroam[TM] have not yet been fully discovered in the wireless community networks aimed at regular consumers. This aim of this…

Utilising eduroam[TM] Architecture in Building Wireless Community Networks

ERIC Educational Resources Information Center

Huhtanen, Karri; Vatiainen, Heikki; Keski-Kasari, Sami; Harju, Jarmo

2008-01-01

Purpose: eduroam[TM] has already been proved to be a scalable, secure and feasible way for universities and research institutions to connect their wireless networks into a WLAN roaming community, but the advantages of eduroam[TM] have not yet been fully discovered in the wireless community networks aimed at regular consumers. This aim of this…

Iowa State University – Final Report for SciDAC3/NUCLEI

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

Vary, James P

The Iowa State University (ISU) contributions to the NUCLEI project are focused on developing, implementing and running an efficient and scalable configuration interaction code (Many-Fermion Dynamics – nuclear or MFDn) for leadership class supercomputers addressing forefront research problems in low-energy nuclear physics. We investigate nuclear structure and reactions with realistic nucleon-nucleon (NN) and three-nucleon (3N) interactions. We select a few highlights from our work that has produced a total of more than 82 refereed publications and more than 109 invited talks under SciDAC3/NUCLEI.

A New Unified Analysis of Estimate Errors by Model-Matching Phase-Estimation Methods for Sensorless Drive of Permanent-Magnet Synchronous Motors and New Trajectory-Oriented Vector Control, Part II

NASA Astrophysics Data System (ADS)

Shinnaka, Shinji

This paper presents a new unified analysis of estimate errors by model-matching extended-back-EMF estimation methods for sensorless drive of permanent-magnet synchronous motors. Analytical solutions about estimate errors, whose validity is confirmed by numerical experiments, are rich in universality and applicability. As an example of universality and applicability, a new trajectory-oriented vector control method is proposed, which can realize directly quasi-optimal strategy minimizing total losses with no additional computational loads by simply orienting one of vector-control coordinates to the associated quasi-optimal trajectory. The coordinate orientation rule, which is analytically derived, is surprisingly simple. Consequently the trajectory-oriented vector control method can be applied to a number of conventional vector control systems using model-matching extended-back-EMF estimation methods.

An intrinsic poperty of memory of the Cellular automaton infrastructure of Nature leading to the organization of the physical world as an Internet o things; TOE = IOT

NASA Astrophysics Data System (ADS)

Berkovich, Simon

2015-04-01

The undamental advantage of a Cellular automaton construction foris that it can be viewed as an undetectable absolute frame o reference, in accordance with Lorentz-Poincare's interpretation.. The cellular automaton model for physical poblems comes upon two basic hurdles: (1) How to find the Elemental Rule that, and how to get non-locality from local transformations. Both problems are resolved considering the transfomation rule of mutual distributed synchronization Actually any information proessing device starts with a clocking system. and it turns out that ``All physical phenomena are different aspects of the high-level description of distributed mutual synchronization in a network of digital clocks''. Non-locality comes from two hugely different time-scales of signaling.. The universe is acombinines information and matter processes, These fast spreading diffusion wave solutions create the mechanism of the Holographic Universe. And thirdly Disengaged from synchronization, circular counters can perform memory functions by retaining phases of their oscillations, an idea of Von Neumann'. Thus, the suggested model generates the necessary constructs for the physical world as an Internet of Things. Life emerges due to the specifics of macromolecules that serve as communication means, with the holographic memory...

Internet-Based Laboratory Immersion: When The Real Deal is Not Available

NASA Astrophysics Data System (ADS)

Meisner, Gerald; Hoffman, Harol

2004-11-01

Do you want all of your students to investigate equilibrium conditions in the physics lab, but don't have time for lab investigations? Do your under-prepared students need basic, careful and detailed remedial work to help them succeed? LAAPhysics provides an answer to these questions by means of robust online physics courseware based on: (1) a sound, research-based pedagogy (2) a rich laboratory environment with skills and operational knowledge transferable to the wet lab' and (3) a paradigm which is economically scalable. LAAPhysics provides both synchronous and asynchronous learning experiences for an introductory, algebra-based course for students (undergraduate, AP High School, seekers of a second degree), those seeking career changes, and pre-service and in-service teachers. We have developed a simulated physics laboratory comprised of virtual lab equipment and instruments, associated curriculum modules and virtual guidance for real time feedback, formative assessment and collaborative learning.

Approximate Computing Techniques for Iterative Graph Algorithms

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

Panyala, Ajay R.; Subasi, Omer; Halappanavar, Mahantesh

Approximate computing enables processing of large-scale graphs by trading off quality for performance. Approximate computing techniques have become critical not only due to the emergence of parallel architectures but also the availability of large scale datasets enabling data-driven discovery. Using two prototypical graph algorithms, PageRank and community detection, we present several approximate computing heuristics to scale the performance with minimal loss of accuracy. We present several heuristics including loop perforation, data caching, incomplete graph coloring and synchronization, and evaluate their efficiency. We demonstrate performance improvements of up to 83% for PageRank and up to 450x for community detection, with lowmore » impact of accuracy for both the algorithms. We expect the proposed approximate techniques will enable scalable graph analytics on data of importance to several applications in science and their subsequent adoption to scale similar graph algorithms.« less

Naver: a PC-cluster-based VR system

NASA Astrophysics Data System (ADS)

Park, ChangHoon; Ko, HeeDong; Kim, TaiYun

2003-04-01

In this paper, we present a new framework NAVER for virtual reality application. The NAVER is based on a cluster of low-cost personal computers. The goal of NAVER is to provide flexible, extensible, scalable and re-configurable framework for the virtual environments defined as the integration of 3D virtual space and external modules. External modules are various input or output devices and applications on the remote hosts. From the view of system, personal computers are divided into three servers according to its specific functions: Render Server, Device Server and Control Server. While Device Server contains external modules requiring event-based communication for the integration, Control Server contains external modules requiring synchronous communication every frame. And, the Render Server consists of 5 managers: Scenario Manager, Event Manager, Command Manager, Interaction Manager and Sync Manager. These managers support the declaration and operation of virtual environment and the integration with external modules on remote servers.

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

High repetition rate tunable femtosecond pulses and broadband amplification from fiber laser pumped parametric amplifier.

PubMed

Andersen, T V; Schmidt, O; Bruchmann, C; Limpert, J; Aguergaray, C; Cormier, E; Tünnermann, A

2006-05-29

We report on the generation of high energy femtosecond pulses at 1 MHz repetition rate from a fiber laser pumped optical parametric amplifier (OPA). Nonlinear bandwidth enhancement in fibers provides the intrinsically synchronized signal for the parametric amplifier. We demonstrate large tunability extending from 700 nm to 1500 nm of femtosecond pulses with pulse energies as high as 1.2 muJ when the OPA is seeded by a supercontinuum generated in a photonic crystal fiber. Broadband amplification over more than 85 nm is achieved at a fixed wavelength. Subsequent compression in a prism sequence resulted in 46 fs pulses. With an average power of 0.5 W these pulses have a peak-power above 10 MW. In particular, the average power and pulse energy scalability of both involved concepts, the fiber laser and the parametric amplifier, will enable easy up-scaling to higher powers.

A Conceptual Design for a Reliable Optical Bus (ROBUS)

NASA Technical Reports Server (NTRS)

Miner, Paul S.; Malekpour, Mahyar; Torres, Wilfredo

2002-01-01

The Scalable Processor-Independent Design for Electromagnetic Resilience (SPIDER) is a new family of fault-tolerant architectures under development at NASA Langley Research Center (LaRC). The SPIDER is a general-purpose computational platform suitable for use in ultra-reliable embedded control applications. The design scales from a small configuration supporting a single aircraft function to a large distributed configuration capable of supporting several functions simultaneously. SPIDER consists of a collection of simplex processing elements communicating via a Reliable Optical Bus (ROBUS). The ROBUS is an ultra-reliable, time-division multiple access broadcast bus with strictly enforced write access (no babbling idiots) providing basic fault-tolerant services using formally verified fault-tolerance protocols including Interactive Consistency (Byzantine Agreement), Internal Clock Synchronization, and Distributed Diagnosis. The conceptual design of the ROBUS is presented in this paper including requirements, topology, protocols, and the block-level design. Verification activities, including the use of formal methods, are also discussed.

On the long-period evolution of the sun-synchronous orbits

NASA Astrophysics Data System (ADS)

Kuznetsov, E. D.; Jasim, A. T.

2016-05-01

The dynamic evolution of sun-synchronous orbits at a time interval of 20 years is considered. The numerical motion simulation has been carried out using the Celestial Mechanics software package developed at the Institute of Astronomy of the University of Bern. The dependence of the dynamic evolution on the initial value of the ascending node longitude is examined for two families of sun-synchronous orbits with altitudes of 751 and 1191 km. Variations of the semimajor axis and orbit inclination are obtained depending on the initial value of the ascending node longitude. Recommendations on the selection of orbits, in which spent sun-synchronous satellites can be moved, are formulated. Minimal changes of elements over a time interval of 20 years have been observed for orbits in which at the initial time the angle between the orbit ascending node and the direction of the Sun measured along the equator have been close to 90° or 270°. In this case, the semimajor axis of the orbit is not experiencing secular perturbations arising from the satellite's passage through the Earth's shadow.

Distance learning through synchronous interactive television.

PubMed

Hall, Janis L

2007-01-01

The advent and popularity of asynchronous online learning has somewhat obscured a standby technology developed over the last two decades. Interactive videoconferencing, sometimes called "interactive television," though not as glamorous and popular a topic at distance-learning conferences, is still alive and well at many institutions. Three or four years ago, many of us were led to believe that interactive television would go the way of the dinosaurs-everything would soon be in an asynchronous format or on individual desktops. There would no longer be any need for elaborately designed classrooms, networks, and operations staff. To date, this prediction has not come true. In fact, synchronous interactive television has experienced significant growth as newer, easier, and cheaper technologies allow institutions to reach more students with less resource investment. Faculty and students, while appreciating the convenience of asynchronous delivery, still express a need for synchronous communication. This article explores the issues involved in synchronous distance education, the current technologies and proposed future developments, and best practices in terms of classroom design, faculty use, and operational issues. It is not a research article but an anecdotal case study based on Washington State University's experiences over the last 20 years in developing and adapting to new synchronous technologies and creating the support and technical infrastructure to best deliver academic courses through this medium.

Real-time SHVC software decoding with multi-threaded parallel processing

NASA Astrophysics Data System (ADS)

Gudumasu, Srinivas; He, Yuwen; Ye, Yan; He, Yong; Ryu, Eun-Seok; Dong, Jie; Xiu, Xiaoyu

2014-09-01

This paper proposes a parallel decoding framework for scalable HEVC (SHVC). Various optimization technologies are implemented on the basis of SHVC reference software SHM-2.0 to achieve real-time decoding speed for the two layer spatial scalability configuration. SHVC decoder complexity is analyzed with profiling information. The decoding process at each layer and the up-sampling process are designed in parallel and scheduled by a high level application task manager. Within each layer, multi-threaded decoding is applied to accelerate the layer decoding speed. Entropy decoding, reconstruction, and in-loop processing are pipeline designed with multiple threads based on groups of coding tree units (CTU). A group of CTUs is treated as a processing unit in each pipeline stage to achieve a better trade-off between parallelism and synchronization. Motion compensation, inverse quantization, and inverse transform modules are further optimized with SSE4 SIMD instructions. Simulations on a desktop with an Intel i7 processor 2600 running at 3.4 GHz show that the parallel SHVC software decoder is able to decode 1080p spatial 2x at up to 60 fps (frames per second) and 1080p spatial 1.5x at up to 50 fps for those bitstreams generated with SHVC common test conditions in the JCT-VC standardization group. The decoding performance at various bitrates with different optimization technologies and different numbers of threads are compared in terms of decoding speed and resource usage, including processor and memory.

Visualization of cavitation phenomena in a Diesel engine fuel injection nozzle by neutron radiography

NASA Astrophysics Data System (ADS)

Takenaka, N.; Kadowaki, T.; Kawabata, Y.; Lim, I. C.; Sim, C. M.

2005-04-01

Visualization of cavitation phenomena in a Diesel engine fuel injection nozzle was carried out by using neutron radiography system at KUR in Research Reactor Institute in Kyoto University and at HANARO in Korea Atomic Energy Research Institute. A neutron chopper was synchronized to the engine rotation for high shutter speed exposures. A multi-exposure method was applied to obtain a clear image as an ensemble average of the synchronized images. Some images were successfully obtained and suggested new understanding of the cavitation phenomena in a Diesel engine fuel injection nozzle.

Non-conventional synchronization of weakly coupled active oscillators

NASA Astrophysics Data System (ADS)

Manevitch, L. I.; Kovaleva, M. A.; Pilipchuk, V. N.

2013-03-01

We present a new type of self-sustained vibrations in the fundamental physical model covering a broad area of applications from wave generation in radiophysics and nonlinear optics to the heart muscle contraction and eyesight disorder in biophysics. Such a diversity of applications is due to the universal physical phenomenon of synchronization. Previous studies of this phenomenon, originating from Huygens famous observation, are based mainly on the model of two weakly coupled Van der Pol oscillators and usually deal with their synchronization in the regimes close to nonlinear normal modes (NNMs). In this work, we show for the first time that, in the important case of threshold excitation, an alternative synchronization mechanism can develop when the conventional synchronization becomes impossible. We identify this mechanism as an appearance of dynamic attractor with the complete periodic energy exchange between the oscillators, which is the dissipative analogue of highly intensive beats in a conservative system. This type of motion is therefore opposite to the NNM-type synchronization with no energy exchange by definition. The analytical description of these vibrations employs the concept of Limiting Phase Trajectories (LPTs) introduced by one of the authors earlier for conservative systems. Finally, within the LPT approach, we describe the transition from the complete energy exchange between the oscillators to the energy localization mostly on one of the two oscillators. The localized mode is an attractor in the range of model parameters wherein the LPT as well as the in-phase and out-of-phase NNMs become unstable.

Electromagnetic Launchers and Guns. Phase 1

DTIC Science & Technology

1980-06-01

a high-speed maglev transportation system based on a linear synchronous motor (1,2,3). In 1975 Gerard K. O’Neill of Princeton University...fact that the very important railgun- homopolar launcher technology is already being pursued at Westinghouse and university of Texas, Austin. The...shown in Fig. 14 on the following page. There are three comparable options for energy storage: an engine-driven homopolar generator followed by an

Tradeoffs Between Synchronization, Communication, and Work in Parallel Linear Algebra Computations

DTIC Science & Technology

2014-01-25

Demmel Electrical Engineering and Computer Sciences University of California at Berkeley Technical Report No. UCB/EECS-2014- 8 http...www.eecs.berkeley.edu/Pubs/TechRpts/2014/EECS-2014- 8 .html January 25, 2014 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the...University of California at Berkeley,Electrical Engineering and Computer Sciences,Berkeley,CA,94720 8 . PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING

Challenge-based instruction in biomedical engineering: a scalable method to increase the efficiency and effectiveness of teaching and learning in biomedical engineering.

PubMed

Harris, Thomas R; Brophy, Sean P

2005-09-01

Vanderbilt University, Northwestern University, the University of Texas and the Harvard/MIT Health Sciences Technology Program have collaborated since 1999 to develop means to improve bioengineering education. This effort, funded by the National Science Foundation as the VaNTH Engineering Research Center in Bioengineering Educational Technologies, has sought a synthesis of learning science, learning technology, assessment and the domains of bioengineering in order to improve learning by bioengineering students. Research has shown that bioengineering educational materials may be designed to emphasize challenges that engage the student and, when coupled with a learning cycle and appropriate technologies, can lead to improvements in instruction.

Blueprint for a microwave trapped ion quantum computer.

PubMed

Lekitsch, Bjoern; Weidt, Sebastian; Fowler, Austin G; Mølmer, Klaus; Devitt, Simon J; Wunderlich, Christof; Hensinger, Winfried K

2017-02-01

The availability of a universal quantum computer may have a fundamental impact on a vast number of research fields and on society as a whole. An increasingly large scientific and industrial community is working toward the realization of such a device. An arbitrarily large quantum computer may best be constructed using a modular approach. We present a blueprint for a trapped ion-based scalable quantum computer module, making it possible to create a scalable quantum computer architecture based on long-wavelength radiation quantum gates. The modules control all operations as stand-alone units, are constructed using silicon microfabrication techniques, and are within reach of current technology. To perform the required quantum computations, the modules make use of long-wavelength radiation-based quantum gate technology. To scale this microwave quantum computer architecture to a large size, we present a fully scalable design that makes use of ion transport between different modules, thereby allowing arbitrarily many modules to be connected to construct a large-scale device. A high error-threshold surface error correction code can be implemented in the proposed architecture to execute fault-tolerant operations. With appropriate adjustments, the proposed modules are also suitable for alternative trapped ion quantum computer architectures, such as schemes using photonic interconnects.

The Advance of the MOOCs (Massive Open Online Courses): The Impending Globalisation of Business Education?

ERIC Educational Resources Information Center

Clarke, Thomas

2013-01-01

Purpose: The purpose of this paper is to analyse the rapid development of the massive open online courses (MOOCs) and the implications for business education, to critically examine the educational and business models of the MOOCs, to assess their present scale and scalability, and to explore the responses of the universities to this challenge.…

Synchronization of eukaryotic flagella in vivo: from two to thousands

NASA Astrophysics Data System (ADS)

Goldstein, Raymond E.

2012-02-01

From unicellular organisms as small as a few microns to the largest vertebrates on Earth, we find groups of beating flagella or cilia that exhibit striking spatiotemporal organization. This may take the form of precise frequency and phase locking, as frequently found in the swimming of green algae, or beating with long-wavelength phase modulations known as metachronal waves, seen in ciliates such as Paramecium and in our own respiratory systems. The remarkable similarity in the underlying molecular structure of flagella across the whole eukaryotic world leads naturally to the hypothesis that a similarly universal mechanism might be responsible for synchronization. Although this mechanism is poorly understood, one appealing hypothesis is that it results from hydrodynamic interactions between flagella. This talk will summarize recent work using the unicellular alga Chlamydomonas reinhardtii and its multicellular cousin Volvox carteri to study in detail the nature of flagellar synchronization and its possible hydrodynamic origins.

Thermal coupling and effect of subharmonic synchronization in a system of two VO2 based oscillators

NASA Astrophysics Data System (ADS)

Velichko, Andrey; Belyaev, Maksim; Putrolaynen, Vadim; Perminov, Valentin; Pergament, Alexander

2018-03-01

We explore a prototype of an oscillatory neural network (ONN) based on vanadium dioxide switching devices. The model system under study represents two oscillators based on thermally coupled VO2 switches. Numerical simulation shows that the effective action radius RTC of coupling depends both on the total energy released during switching and on the average power. It is experimentally and numerically proved that the temperature change ΔT commences almost synchronously with the released power peak and T-coupling reveals itself up to a frequency of about 10 kHz. For the studied switching structure configuration, the RTC value varies over a wide range from 4 to 45 μm, depending on the external circuit capacitance C and resistance Ri, but the variation of Ri is more promising from the practical viewpoint. In the case of a "weak" coupling, synchronization is accompanied by attraction effect and decrease of the main spectra harmonics width. In the case of a "strong" coupling, the number of effects increases, synchronization can occur on subharmonics resulting in multilevel stable synchronization of two oscillators. An advanced algorithm for synchronization efficiency and subharmonic ratio calculation is proposed. It is shown that of the two oscillators the leading one is that with a higher main frequency, and, in addition, the frequency stabilization effect is observed. Also, in the case of a strong thermal coupling, the limit of the supply current parameters, for which the oscillations exist, expands by ∼10%. The obtained results have a universal character and open up a new kind of coupling in ONNs, namely, T-coupling, which allows for easy transition from 2D to 3D integration. The effect of subharmonic synchronization hold promise for application in classification and pattern recognition.

Inter-subject synchronization of brain responses during natural music listening.

PubMed

Abrams, Daniel A; Ryali, Srikanth; Chen, Tianwen; Chordia, Parag; Khouzam, Amirah; Levitin, Daniel J; Menon, Vinod

2013-05-01

Music is a cultural universal and a rich part of the human experience. However, little is known about common brain systems that support the processing and integration of extended, naturalistic 'real-world' music stimuli. We examined this question by presenting extended excerpts of symphonic music, and two pseudomusical stimuli in which the temporal and spectral structure of the Natural Music condition were disrupted, to non-musician participants undergoing functional brain imaging and analysing synchronized spatiotemporal activity patterns between listeners. We found that music synchronizes brain responses across listeners in bilateral auditory midbrain and thalamus, primary auditory and auditory association cortex, right-lateralized structures in frontal and parietal cortex, and motor planning regions of the brain. These effects were greater for natural music compared to the pseudo-musical control conditions. Remarkably, inter-subject synchronization in the inferior colliculus and medial geniculate nucleus was also greater for the natural music condition, indicating that synchronization at these early stages of auditory processing is not simply driven by spectro-temporal features of the stimulus. Increased synchronization during music listening was also evident in a right-hemisphere fronto-parietal attention network and bilateral cortical regions involved in motor planning. While these brain structures have previously been implicated in various aspects of musical processing, our results are the first to show that these regions track structural elements of a musical stimulus over extended time periods lasting minutes. Our results show that a hierarchical distributed network is synchronized between individuals during the processing of extended musical sequences, and provide new insight into the temporal integration of complex and biologically salient auditory sequences. © 2013 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Scalable randomized benchmarking of non-Clifford gates

NASA Astrophysics Data System (ADS)

Cross, Andrew; Magesan, Easwar; Bishop, Lev; Smolin, John; Gambetta, Jay

Randomized benchmarking is a widely used experimental technique to characterize the average error of quantum operations. Benchmarking procedures that scale to enable characterization of n-qubit circuits rely on efficient procedures for manipulating those circuits and, as such, have been limited to subgroups of the Clifford group. However, universal quantum computers require additional, non-Clifford gates to approximate arbitrary unitary transformations. We define a scalable randomized benchmarking procedure over n-qubit unitary matrices that correspond to protected non-Clifford gates for a class of stabilizer codes. We present efficient methods for representing and composing group elements, sampling them uniformly, and synthesizing corresponding poly (n) -sized circuits. The procedure provides experimental access to two independent parameters that together characterize the average gate fidelity of a group element. We acknowledge support from ARO under Contract W911NF-14-1-0124.

Ballistic Characterization of the Scalability of Mg Alloy AMX602

NASA Astrophysics Data System (ADS)

Jones, Tyrone L.; Kondoh, Katsuyoshi; Moore, David; Otsuka, Isamu; Annis, Alan; Nakazawa, Hiroto; Ohori, Yoshinori; Numasawa, Ryo; Takahashi, Masamichi

The US Army Research Laboratory (ARL) and the Osaka University Joining and Welding Research Institute (JWRI) formed a collaborative partnership with Taber Extrusions, Epson, Pacific Sowa, Kurimoto, and National Material LP to domestically reproduce and scale-up military grade magnesium alloy AMX602 at the Taber Extrusion manufacturing facility in Gulfport, MS. AMX602 material was provided in the form of 38.1-mm (1.5-inch) wide bars, 101.6-mm (4-inch) wide plate, and 152.4-mm (6-in) wide plate. The ARL and the JWRI conducted mechanical analysis and dynamic impact examination to evaluate the lateral dimension scale-up of AMX602. The results were parametrically analyzed and compared to conventionally processed AZ31B-H24 and AA5083-H131. Details of the scalability of the AMX602 alloy are provided.

A universal exchange language for healthcare.

PubMed

Robson, Barry; Caruso, Thomas P

2013-01-01

We have defined a Universal Exchange Language (UEL) for healthcare that takes a green field approach to the development of a novel "XML-like" language. We consider here what given a free hand might mean: a UEL that incorporates an advanced mathematical foundation that uses Dirac's notation and algebra. For consented and public information, it allows probabilistic inference from UEL semantic web triplet tags. But also it is possible to use similar thinking to maximize the security and analytic characteristics of private health data by disaggregating or "shredding" it. Both are scalable to millions of records that could be spread across the Internet.

An Evaluation of the Network Efficiency Required in Order to Support Multicast and Synchronous Distributed Learning Network Traffic

DTIC Science & Technology

2003-09-01

This restriction limits the deployment to small and medium sized enterprises. The Internet cannot universally use DVMRP for this reason. In addition...20503. 1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE September 2003 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE... University , 1996 Submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN COMPUTER SCIENCE from

Visual Data-Analytics of Large-Scale Parallel Discrete-Event Simulations

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

Ross, Caitlin; Carothers, Christopher D.; Mubarak, Misbah

Parallel discrete-event simulation (PDES) is an important tool in the codesign of extreme-scale systems because PDES provides a cost-effective way to evaluate designs of highperformance computing systems. Optimistic synchronization algorithms for PDES, such as Time Warp, allow events to be processed without global synchronization among the processing elements. A rollback mechanism is provided when events are processed out of timestamp order. Although optimistic synchronization protocols enable the scalability of large-scale PDES, the performance of the simulations must be tuned to reduce the number of rollbacks and provide an improved simulation runtime. To enable efficient large-scale optimistic simulations, one has tomore » gain insight into the factors that affect the rollback behavior and simulation performance. We developed a tool for ROSS model developers that gives them detailed metrics on the performance of their large-scale optimistic simulations at varying levels of simulation granularity. Model developers can use this information for parameter tuning of optimistic simulations in order to achieve better runtime and fewer rollbacks. In this work, we instrument the ROSS optimistic PDES framework to gather detailed statistics about the simulation engine. We have also developed an interactive visualization interface that uses the data collected by the ROSS instrumentation to understand the underlying behavior of the simulation engine. The interface connects real time to virtual time in the simulation and provides the ability to view simulation data at different granularities. We demonstrate the usefulness of our framework by performing a visual analysis of the dragonfly network topology model provided by the CODES simulation framework built on top of ROSS. The instrumentation needs to minimize overhead in order to accurately collect data about the simulation performance. To ensure that the instrumentation does not introduce unnecessary overhead, we perform a scaling study that compares instrumented ROSS simulations with their noninstrumented counterparts in order to determine the amount of perturbation when running at different simulation scales.« less

Virtual machine-based simulation platform for mobile ad-hoc network-based cyber infrastructure

DOE PAGES

Yoginath, Srikanth B.; Perumalla, Kayla S.; Henz, Brian J.

2015-09-29

In modeling and simulating complex systems such as mobile ad-hoc networks (MANETs) in de-fense communications, it is a major challenge to reconcile multiple important considerations: the rapidity of unavoidable changes to the software (network layers and applications), the difficulty of modeling the critical, implementation-dependent behavioral effects, the need to sustain larger scale scenarios, and the desire for faster simulations. Here we present our approach in success-fully reconciling them using a virtual time-synchronized virtual machine(VM)-based parallel ex-ecution framework that accurately lifts both the devices as well as the network communications to a virtual time plane while retaining full fidelity. At themore » core of our framework is a scheduling engine that operates at the level of a hypervisor scheduler, offering a unique ability to execute multi-core guest nodes over multi-core host nodes in an accurate, virtual time-synchronized manner. In contrast to other related approaches that suffer from either speed or accuracy issues, our framework provides MANET node-wise scalability, high fidelity of software behaviors, and time-ordering accuracy. The design and development of this framework is presented, and an ac-tual implementation based on the widely used Xen hypervisor system is described. Benchmarks with synthetic and actual applications are used to identify the benefits of our approach. The time inaccuracy of traditional emulation methods is demonstrated, in comparison with the accurate execution of our framework verified by theoretically correct results expected from analytical models of the same scenarios. In the largest high fidelity tests, we are able to perform virtual time-synchronized simulation of 64-node VM-based full-stack, actual software behaviors of MANETs containing a mix of static and mobile (unmanned airborne vehicle) nodes, hosted on a 32-core host, with full fidelity of unmodified ad-hoc routing protocols, unmodified application executables, and user-controllable physical layer effects including inter-device wireless signal strength, reachability, and connectivity.« less

Virtual machine-based simulation platform for mobile ad-hoc network-based cyber infrastructure

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

Yoginath, Srikanth B.; Perumalla, Kayla S.; Henz, Brian J.

In modeling and simulating complex systems such as mobile ad-hoc networks (MANETs) in de-fense communications, it is a major challenge to reconcile multiple important considerations: the rapidity of unavoidable changes to the software (network layers and applications), the difficulty of modeling the critical, implementation-dependent behavioral effects, the need to sustain larger scale scenarios, and the desire for faster simulations. Here we present our approach in success-fully reconciling them using a virtual time-synchronized virtual machine(VM)-based parallel ex-ecution framework that accurately lifts both the devices as well as the network communications to a virtual time plane while retaining full fidelity. At themore » core of our framework is a scheduling engine that operates at the level of a hypervisor scheduler, offering a unique ability to execute multi-core guest nodes over multi-core host nodes in an accurate, virtual time-synchronized manner. In contrast to other related approaches that suffer from either speed or accuracy issues, our framework provides MANET node-wise scalability, high fidelity of software behaviors, and time-ordering accuracy. The design and development of this framework is presented, and an ac-tual implementation based on the widely used Xen hypervisor system is described. Benchmarks with synthetic and actual applications are used to identify the benefits of our approach. The time inaccuracy of traditional emulation methods is demonstrated, in comparison with the accurate execution of our framework verified by theoretically correct results expected from analytical models of the same scenarios. In the largest high fidelity tests, we are able to perform virtual time-synchronized simulation of 64-node VM-based full-stack, actual software behaviors of MANETs containing a mix of static and mobile (unmanned airborne vehicle) nodes, hosted on a 32-core host, with full fidelity of unmodified ad-hoc routing protocols, unmodified application executables, and user-controllable physical layer effects including inter-device wireless signal strength, reachability, and connectivity.« less

Physiological coherence in healthy volunteers during laboratory-induced stress and controlled breathing.

PubMed

Mejía-Mejía, Elisa; Torres, Robinson; Restrepo, Diana

2018-06-01

Physiological coherence has been related with a general sense of well-being and improvements in health and physical, social, and cognitive performance. The aim of this study was to evaluate the relationship between acute stress, controlled breathing, and physiological coherence, and the degree of body systems synchronization during a coherence-generation exercise. Thirty-four university employees were evaluated during a 20-min test consisting of four stages of 5-min duration each, during which basal measurements were obtained (Stage 1), acute stress was induced using validated mental stressors (Stroop test and mental arithmetic task, during Stage 2 and 3, respectively), and coherence states were generated using a controlled breathing technique (Stage 4). Physiological coherence and cardiorespiratory synchronization were assessed during each stage from heart rate variability, pulse transit time, and respiration. Coherence measurements derived from the three analyzed variables increased during controlled respiration. Moreover, signals synchronized during the controlled breathing stage, implying a cardiorespiratory synchronization was achieved by most participants. Hence, physiological coherence and cardiopulmonary synchronization, which could lead to improvements in health and better life quality, can be achieved using slow, controlled breathing exercises. Meanwhile, coherence measured during basal state and stressful situations did not show relevant differences using heart rate variability and pulse transit time. More studies are needed to evaluate the ability of coherence ratio to reflect acute stress. © 2017 Society for Psychophysiological Research.

Griffin: A Tool for Symbolic Inference of Synchronous Boolean Molecular Networks.

PubMed

Muñoz, Stalin; Carrillo, Miguel; Azpeitia, Eugenio; Rosenblueth, David A

2018-01-01

Boolean networks are important models of biochemical systems, located at the high end of the abstraction spectrum. A number of Boolean gene networks have been inferred following essentially the same method. Such a method first considers experimental data for a typically underdetermined "regulation" graph. Next, Boolean networks are inferred by using biological constraints to narrow the search space, such as a desired set of (fixed-point or cyclic) attractors. We describe Griffin , a computer tool enhancing this method. Griffin incorporates a number of well-established algorithms, such as Dubrova and Teslenko's algorithm for finding attractors in synchronous Boolean networks. In addition, a formal definition of regulation allows Griffin to employ "symbolic" techniques, able to represent both large sets of network states and Boolean constraints. We observe that when the set of attractors is required to be an exact set, prohibiting additional attractors, a naive Boolean coding of this constraint may be unfeasible. Such cases may be intractable even with symbolic methods, as the number of Boolean constraints may be astronomically large. To overcome this problem, we employ an Artificial Intelligence technique known as "clause learning" considerably increasing Griffin 's scalability. Without clause learning only toy examples prohibiting additional attractors are solvable: only one out of seven queries reported here is answered. With clause learning, by contrast, all seven queries are answered. We illustrate Griffin with three case studies drawn from the Arabidopsis thaliana literature. Griffin is available at: http://turing.iimas.unam.mx/griffin.

Fast and Accurate Support Vector Machines on Large Scale Systems

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

Vishnu, Abhinav; Narasimhan, Jayenthi; Holder, Larry

Support Vector Machines (SVM) is a supervised Machine Learning and Data Mining (MLDM) algorithm, which has become ubiquitous largely due to its high accuracy and obliviousness to dimensionality. The objective of SVM is to find an optimal boundary --- also known as hyperplane --- which separates the samples (examples in a dataset) of different classes by a maximum margin. Usually, very few samples contribute to the definition of the boundary. However, existing parallel algorithms use the entire dataset for finding the boundary, which is sub-optimal for performance reasons. In this paper, we propose a novel distributed memory algorithm to eliminatemore » the samples which do not contribute to the boundary definition in SVM. We propose several heuristics, which range from early (aggressive) to late (conservative) elimination of the samples, such that the overall time for generating the boundary is reduced considerably. In a few cases, a sample may be eliminated (shrunk) pre-emptively --- potentially resulting in an incorrect boundary. We propose a scalable approach to synchronize the necessary data structures such that the proposed algorithm maintains its accuracy. We consider the necessary trade-offs of single/multiple synchronization using in-depth time-space complexity analysis. We implement the proposed algorithm using MPI and compare it with libsvm--- de facto sequential SVM software --- which we enhance with OpenMP for multi-core/many-core parallelism. Our proposed approach shows excellent efficiency using up to 4096 processes on several large datasets such as UCI HIGGS Boson dataset and Offending URL dataset.« less

Parallel computing of physical maps--a comparative study in SIMD and MIMD parallelism.

PubMed

Bhandarkar, S M; Chirravuri, S; Arnold, J

1996-01-01

Ordering clones from a genomic library into physical maps of whole chromosomes presents a central computational problem in genetics. Chromosome reconstruction via clone ordering is usually isomorphic to the NP-complete Optimal Linear Arrangement problem. Parallel SIMD and MIMD algorithms for simulated annealing based on Markov chain distribution are proposed and applied to the problem of chromosome reconstruction via clone ordering. Perturbation methods and problem-specific annealing heuristics are proposed and described. The SIMD algorithms are implemented on a 2048 processor MasPar MP-2 system which is an SIMD 2-D toroidal mesh architecture whereas the MIMD algorithms are implemented on an 8 processor Intel iPSC/860 which is an MIMD hypercube architecture. A comparative analysis of the various SIMD and MIMD algorithms is presented in which the convergence, speedup, and scalability characteristics of the various algorithms are analyzed and discussed. On a fine-grained, massively parallel SIMD architecture with a low synchronization overhead such as the MasPar MP-2, a parallel simulated annealing algorithm based on multiple periodically interacting searches performs the best. For a coarse-grained MIMD architecture with high synchronization overhead such as the Intel iPSC/860, a parallel simulated annealing algorithm based on multiple independent searches yields the best results. In either case, distribution of clonal data across multiple processors is shown to exacerbate the tendency of the parallel simulated annealing algorithm to get trapped in a local optimum.

Nanotechnology: A Policy Primer

DTIC Science & Technology

2008-05-20

of oil.3 ! Universal access to clean water. Nanotechnology water desalination and filtration systems may offer affordable, scalable, and portable...Order Code RL34511 Nanotechnology : A Policy Primer May 20, 2008 John F. Sargent Specialist in Science and Technology Policy Resources, Science, and...REPORT DATE 20 MAY 2008 2. REPORT TYPE 3. DATES COVERED 00-00-2008 to 00-00-2008 4. TITLE AND SUBTITLE Nanotechnology : A Policy Primer 5a

Development of the Novel e-Learning System, "SPES NOVA" (Scalable Personality-Adapted Education System with Networking of Views and Activities)

ERIC Educational Resources Information Center

Takeuchi, Ken; Murakami, Manabu; Kato, Atsushi; Akiyama, Ryuichi; Honda, Hirotaka; Nozawa, Hajime; Sato, Ki-ichiro

2009-01-01

The Faculty of Industrial Science and Technology at Tokyo University of Science developed a two-campus system to produce well-trained engineers possessing both technical and humanistic traits. In their first year of study, students reside in dormitories in the natural setting of the Oshamambe campus located in Hokkaido, Japan. The education…

Entanglement in a Quantum Annealing Processor

DTIC Science & Technology

2016-09-07

that QA is a viable technology for large- scale quantum computing . DOI: 10.1103/PhysRevX.4.021041 Subject Areas: Quantum Physics, Quantum Information...Superconductivity I. INTRODUCTION The past decade has been exciting for the field of quantum computation . A wide range of physical imple- mentations...measurements used in studying prototype universal quantum computers [9–14]. These constraints make it challenging to experimentally determine whether a scalable

Maturity Assessment of Space Plug-and-Play Architecture

DTIC Science & Technology

2013-03-01

SSM SPA Service Module SRL System Readiness Level TAT Time-at-Tone TRA Technology Readiness Assessment TRL Technology Readiness Level USB Universal...maturity assessment—the Technology Readiness Level (TRL) process, the Integration Readiness Level (IRL) process, and the System Readiness Level ( SRL ...is an important hallmark of the SPA concept, and makes possible the composability and scalability of system designs that employ it. 14 4. SPA

Think 500, not 50! A scalable approach to student success in STEM.

PubMed

LaCourse, William R; Sutphin, Kathy Lee; Ott, Laura E; Maton, Kenneth I; McDermott, Patrice; Bieberich, Charles; Farabaugh, Philip; Rous, Philip

2017-01-01

UMBC, a diverse public research university, "builds" upon its reputation in producing highly capable undergraduate scholars to create a comprehensive new model, STEM BUILD at UMBC. This program is designed to help more students develop the skills, experience and motivation to excel in science, technology, engineering, and mathematics (STEM). This article provides an in-depth description of STEM BUILD at UMBC and provides the context of this initiative within UMBC's vision and mission. The STEM BUILD model targets promising STEM students who enter as freshmen or transfer students and do not qualify for significant university or other scholarship support. Of primary importance to this initiative are capacity, scalability, and institutional sustainability, as we distill the advantages and opportunities of UMBC's successful scholars programs and expand their application to more students. The general approach is to infuse the mentoring and training process into the fabric of the undergraduate experience while fostering community, scientific identity, and resilience. At the heart of STEM BUILD at UMBC is the development of BUILD Group Research (BGR), a sequence of experiences designed to overcome the challenges that undergraduates without programmatic support often encounter (e.g., limited internship opportunities, mentorships, and research positions for which top STEM students are favored). BUILD Training Program (BTP) Trainees serve as pioneers in this initiative, which is potentially a national model for universities as they address the call to retain and graduate more students in STEM disciplines - especially those from underrepresented groups. As such, BTP is a research study using random assignment trial methodology that focuses on the scalability and eventual incorporation of successful measures into the traditional format of the academy. Critical measures to transform institutional culture include establishing an extensive STEM Living and Learning Community to increase undergraduate retention, expanding the adoption of "active learning" pedagogies to increase the efficiency of learning, and developing programs to train researchers to effectively mentor a greater portion of the student population. The overarching goal of STEM BUILD at UMBC is to retain students in STEM majors and better prepare them for post baccalaureate, graduate, or professional programs as well as careers in biomedical and behavioral research.

Simulating Behavioural Interviews Using Synchronous Communication Software: Elluminate Live

ERIC Educational Resources Information Center

Sponza, Maria

2011-01-01

This practice application brief reviews the preparation, implementation, and evaluation of running behavioural interviews online. In a collaborative program between the School of Information Technology and the Careers and Employment service at Deakin University in Australia, students demonstrated their ability to articulate their generic…

Blending Online and Traditional Instruction in the Mathematics Classroom.

ERIC Educational Resources Information Center

Abrams, Gene; Haefner, Jeremy

2002-01-01

Describes the MathOnline system at the University of Colorado (Colorado Springs), a learning delivery method that, in addition to blending synchronous and asynchronous learning, combines traditional mathematics instruction with distance learning. Student surveys indicate the system greatly enhances traditional learners' educational experiences…

A New Unified Analysis of Estimate Errors by Model-Matching Phase-Estimation Methods for Sensorless Drive of Permanent-Magnet Synchronous Motors and New Trajectory-Oriented Vector Control, Part I

NASA Astrophysics Data System (ADS)

Shinnaka, Shinji; Sano, Kousuke

This paper presents a new unified analysis of estimate errors by model-matching phase-estimation methods such as rotor-flux state-observers, back EMF state-observers, and back EMF disturbance-observers, for sensorless drive of permanent-magnet synchronous motors. Analytical solutions about estimate errors, whose validity is confirmed by numerical experiments, are rich in universality and applicability. As an example of universality and applicability, a new trajectory-oriented vector control method is proposed, which can realize directly quasi-optimal strategy minimizing total losses with no additional computational loads by simply orienting one of vector-control coordinates to the associated quasi-optimal trajectory. The coordinate orientation rule, which is analytically derived, is surprisingly simple. Consequently the trajectory-oriented vector control method can be applied to a number of conventional vector control systems using one of the model-matching phase-estimation methods.

Scalable Collaborative Infrastructure for a Learning Healthcare System (SCILHS): Architecture

PubMed Central

Mandl, Kenneth D; Kohane, Isaac S; McFadden, Douglas; Weber, Griffin M; Natter, Marc; Mandel, Joshua; Schneeweiss, Sebastian; Weiler, Sarah; Klann, Jeffrey G; Bickel, Jonathan; Adams, William G; Ge, Yaorong; Zhou, Xiaobo; Perkins, James; Marsolo, Keith; Bernstam, Elmer; Showalter, John; Quarshie, Alexander; Ofili, Elizabeth; Hripcsak, George; Murphy, Shawn N

2014-01-01

We describe the architecture of the Patient Centered Outcomes Research Institute (PCORI) funded Scalable Collaborative Infrastructure for a Learning Healthcare System (SCILHS, http://www.SCILHS.org) clinical data research network, which leverages the $48 billion dollar federal investment in health information technology (IT) to enable a queryable semantic data model across 10 health systems covering more than 8 million patients, plugging universally into the point of care, generating evidence and discovery, and thereby enabling clinician and patient participation in research during the patient encounter. Central to the success of SCILHS is development of innovative ‘apps’ to improve PCOR research methods and capacitate point of care functions such as consent, enrollment, randomization, and outreach for patient-reported outcomes. SCILHS adapts and extends an existing national research network formed on an advanced IT infrastructure built with open source, free, modular components. PMID:24821734

CATSAT: A small satellite for studying gamma-ray bursts

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

Vestrand, W. T.; NIS-2, Los Alamos National Laboratory, Los Alamos, New Mexico 87545; Forrest, D. J.

1999-12-15

The Cooperative Astrophysics and Technology Satellite (CATSAT) is a University Explorer (UNEX) Class Mission that is being constructed by the University of New Hampshire and the University of Leicester. The primary scientific goal of the mission is to study the spectral properties of gamma-ray bursts in the energy range range from 500 eV to 5 MeV with particular emphasis on the 500 eV to 10 keV energy band. The satellite will be zenith pointed and flown in a 590 km sun-synchronous terminator orbit. Here we briefly discuss the mission and the expected scientific results.

A slotted access control protocol for metropolitan WDM ring networks

NASA Astrophysics Data System (ADS)

Baziana, P. A.; Pountourakis, I. E.

2009-03-01

In this study we focus on the serious scalability problems that many access protocols for WDM ring networks introduce due to the use of a dedicated wavelength per access node for either transmission or reception. We propose an efficient slotted MAC protocol suitable for WDM ring metropolitan area networks. The proposed network architecture employs a separate wavelength for control information exchange prior to the data packet transmission. Each access node is equipped with a pair of tunable transceivers for data communication and a pair of fixed tuned transceivers for control information exchange. Also, each access node includes a set of fixed delay lines for synchronization reasons; to keep the data packets, while the control information is processed. An efficient access algorithm is applied to avoid both the data wavelengths and the receiver collisions. In our protocol, each access node is capable of transmitting and receiving over any of the data wavelengths, facing the scalability issues. Two different slot reuse schemes are assumed: the source and the destination stripping schemes. For both schemes, performance measures evaluation is provided via an analytic model. The analytical results are validated by a discrete event simulation model that uses Poisson traffic sources. Simulation results show that the proposed protocol manages efficient bandwidth utilization, especially under high load. Also, comparative simulation results prove that our protocol achieves significant performance improvement as compared with other WDMA protocols which restrict transmission over a dedicated data wavelength. Finally, performance measures evaluation is explored for diverse numbers of buffer size, access nodes and data wavelengths.

Assessing Ongoing Electronic Resource Purchases: Linking Tools to Synchronize Staff Workflows

ERIC Educational Resources Information Center

Carroll, Jeffrey D.; Major, Colleen; O'Neal, Nada; Tofanelli, John

2012-01-01

Ongoing electronic resource purchases represent a substantial proportion of collections budgets. Recognizing the necessity of systematic ongoing assessment with full selector engagement, Columbia University Libraries appointed an Electronic Resources Assessment Working Group to promote the inclusion of such resources within our current culture of…

Enhancing Practicum Supervision with Asynchronous and Synchronous Technologies

ERIC Educational Resources Information Center

Teo, Yiong Hwee; McNamara, Sue; Romeo, Geoff; Gronn, Donna

2015-01-01

Three video/web conferencing technologies (Pocket Camcorder, Skype, Adobe Connect) were used in regional schools in Australia to determine whether the technologies are appropriate for the needs of the university supervisor, trainee teachers and supervising teachers with regard to practicum teaching placements. Findings revealed that Pocket…

Collaborative International Education: Reaching across Borders

ERIC Educational Resources Information Center

Hilgers, Michael G.; Flachsbart, Barry B.; Elrod, Cassandra C.

2012-01-01

Purpose: As international boundaries fade and financial pressures increase, universities are redefining the norm in educational models. The move from a synchronous classroom to a blended classroom or a completely asynchronous environment has forced faculty to be creative in delivery while overcoming complexities in the associated infrastructure.…

SparkSeq: fast, scalable and cloud-ready tool for the interactive genomic data analysis with nucleotide precision.

PubMed

Wiewiórka, Marek S; Messina, Antonio; Pacholewska, Alicja; Maffioletti, Sergio; Gawrysiak, Piotr; Okoniewski, Michał J

2014-09-15

Many time-consuming analyses of next -: generation sequencing data can be addressed with modern cloud computing. The Apache Hadoop-based solutions have become popular in genomics BECAUSE OF: their scalability in a cloud infrastructure. So far, most of these tools have been used for batch data processing rather than interactive data querying. The SparkSeq software has been created to take advantage of a new MapReduce framework, Apache Spark, for next-generation sequencing data. SparkSeq is a general-purpose, flexible and easily extendable library for genomic cloud computing. It can be used to build genomic analysis pipelines in Scala and run them in an interactive way. SparkSeq opens up the possibility of customized ad hoc secondary analyses and iterative machine learning algorithms. This article demonstrates its scalability and overall fast performance by running the analyses of sequencing datasets. Tests of SparkSeq also prove that the use of cache and HDFS block size can be tuned for the optimal performance on multiple worker nodes. Available under open source Apache 2.0 license: https://bitbucket.org/mwiewiorka/sparkseq/. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Blueprint for a microwave trapped ion quantum computer

PubMed Central

Lekitsch, Bjoern; Weidt, Sebastian; Fowler, Austin G.; Mølmer, Klaus; Devitt, Simon J.; Wunderlich, Christof; Hensinger, Winfried K.

2017-01-01

The availability of a universal quantum computer may have a fundamental impact on a vast number of research fields and on society as a whole. An increasingly large scientific and industrial community is working toward the realization of such a device. An arbitrarily large quantum computer may best be constructed using a modular approach. We present a blueprint for a trapped ion–based scalable quantum computer module, making it possible to create a scalable quantum computer architecture based on long-wavelength radiation quantum gates. The modules control all operations as stand-alone units, are constructed using silicon microfabrication techniques, and are within reach of current technology. To perform the required quantum computations, the modules make use of long-wavelength radiation–based quantum gate technology. To scale this microwave quantum computer architecture to a large size, we present a fully scalable design that makes use of ion transport between different modules, thereby allowing arbitrarily many modules to be connected to construct a large-scale device. A high error–threshold surface error correction code can be implemented in the proposed architecture to execute fault-tolerant operations. With appropriate adjustments, the proposed modules are also suitable for alternative trapped ion quantum computer architectures, such as schemes using photonic interconnects. PMID:28164154

Universal quantum gate set approaching fault-tolerant thresholds with superconducting qubits.

PubMed

Chow, Jerry M; Gambetta, Jay M; Córcoles, A D; Merkel, Seth T; Smolin, John A; Rigetti, Chad; Poletto, S; Keefe, George A; Rothwell, Mary B; Rozen, J R; Ketchen, Mark B; Steffen, M

2012-08-10

We use quantum process tomography to characterize a full universal set of all-microwave gates on two superconducting single-frequency single-junction transmon qubits. All extracted gate fidelities, including those for Clifford group generators, single-qubit π/4 and π/8 rotations, and a two-qubit controlled-not, exceed 95% (98%), without (with) subtracting state preparation and measurement errors. Furthermore, we introduce a process map representation in the Pauli basis which is visually efficient and informative. This high-fidelity gate set serves as a critical building block towards scalable architectures of superconducting qubits for error correction schemes and pushes up on the known limits of quantum gate characterization.

Universal Quantum Computing with Measurement-Induced Continuous-Variable Gate Sequence in a Loop-Based Architecture.

PubMed

Takeda, Shuntaro; Furusawa, Akira

2017-09-22

We propose a scalable scheme for optical quantum computing using measurement-induced continuous-variable quantum gates in a loop-based architecture. Here, time-bin-encoded quantum information in a single spatial mode is deterministically processed in a nested loop by an electrically programmable gate sequence. This architecture can process any input state and an arbitrary number of modes with almost minimum resources, and offers a universal gate set for both qubits and continuous variables. Furthermore, quantum computing can be performed fault tolerantly by a known scheme for encoding a qubit in an infinite-dimensional Hilbert space of a single light mode.

Universal Quantum Computing with Measurement-Induced Continuous-Variable Gate Sequence in a Loop-Based Architecture

NASA Astrophysics Data System (ADS)

Takeda, Shuntaro; Furusawa, Akira

2017-09-01

We propose a scalable scheme for optical quantum computing using measurement-induced continuous-variable quantum gates in a loop-based architecture. Here, time-bin-encoded quantum information in a single spatial mode is deterministically processed in a nested loop by an electrically programmable gate sequence. This architecture can process any input state and an arbitrary number of modes with almost minimum resources, and offers a universal gate set for both qubits and continuous variables. Furthermore, quantum computing can be performed fault tolerantly by a known scheme for encoding a qubit in an infinite-dimensional Hilbert space of a single light mode.

Universal Quantum Gate Set Approaching Fault-Tolerant Thresholds with Superconducting Qubits

NASA Astrophysics Data System (ADS)

Chow, Jerry M.; Gambetta, Jay M.; Córcoles, A. D.; Merkel, Seth T.; Smolin, John A.; Rigetti, Chad; Poletto, S.; Keefe, George A.; Rothwell, Mary B.; Rozen, J. R.; Ketchen, Mark B.; Steffen, M.

2012-08-01

We use quantum process tomography to characterize a full universal set of all-microwave gates on two superconducting single-frequency single-junction transmon qubits. All extracted gate fidelities, including those for Clifford group generators, single-qubit π/4 and π/8 rotations, and a two-qubit controlled-not, exceed 95% (98%), without (with) subtracting state preparation and measurement errors. Furthermore, we introduce a process map representation in the Pauli basis which is visually efficient and informative. This high-fidelity gate set serves as a critical building block towards scalable architectures of superconducting qubits for error correction schemes and pushes up on the known limits of quantum gate characterization.

[Melatonin as a universal stabilizing factor of mental activity].

PubMed

Arushanian, Ē B

2011-01-01

Pineal hormone melatonin stabilizes mental activity of man and animals due to its somnogenic, anxiolytic, antidepressant and nootropic properties. Melatonin effects are based on the synchronization of biological rhythms via the influence on the cerebral structures which control biological rhythms and emotions and normalize endocrine and immune state.

Automated Content Synthesis for Interactive Remote Instruction.

ERIC Educational Resources Information Center

Maly, K.; Overstreet, C. M.; Gonzalez, A.; Denbar, M. L.; Cutaran, R.; Karunaratne, N.

This paper describes IRI (Interactive Remote Instruction), a computer-based system built at Old Dominion University (Virginia) in order to support distance education. The system is based on the concept of a virtual classroom where students at different locations have the same synchronous class experience, using networked computers to communicate…

Chomsky's 'Ideal' Native Speaker: Sexism in Synchronic Linguistics.

ERIC Educational Resources Information Center

Stanley, Julia Penelope

Drawing on recent research on sexism in English and the ways in which social forces affect language structure, this paper shows how prescriptive statements about English have been incorporated into linguistic grammars as descriptions of language. It is claimed that Chomsky's "universal grammar" is masculinist and that it is contradicted…

Creating a Rich Learning Environment for Remote Postgraduate Learners

ERIC Educational Resources Information Center

Lonie, Anne-Louise; Andrews, Trish

2009-01-01

At Rangelands Australia, a centre in the School of Natural and Rural Systems Management at the University of Queensland, we have recently trialled virtual classroom technology for the delivery of postgraduate support courses. We wanted to explore the capacity of this learning modality to provide collaborative, interactive, synchronous learning…

Investigating L2 Performance in Text Chat

ERIC Educational Resources Information Center

Sauro, Shannon; Smith, Bryan

2010-01-01

This study examines the linguistic complexity and lexical diversity of both overt and covert L2 output produced during synchronous written computer-mediated communication, also referred to as chat. Video enhanced chatscripts produced by university learners of German (N = 23) engaged in dyadic task-based chat interaction were coded and analyzed for…

How "Blended" Should "Blended Learning" Be?

ERIC Educational Resources Information Center

Ostrowski, Boguslaw; Windeatt, Scott; Clark, Jill

2017-01-01

Concerns about progression rates of international students enrolled in an academic English course to prepare them for university studies led to the addition of an online teaching component, including both synchronous and asynchronous elements. Due to what appeared to be inconsistent student engagement with the online element, this study was…

Web-Based Architecture to Enable Compute-Intensive CAD Tools and Multi-user Synchronization in Teleradiology

NASA Astrophysics Data System (ADS)

Mehta, Neville; Kompalli, Suryaprakash; Chaudhary, Vipin

Teleradiology is the electronic transmission of radiological patient images, such as x-rays, CT, or MR across multiple locations. The goal could be interpretation, consultation, or medical records keeping. Information technology solutions have enabled electronic records and their associated benefits are evident in health care today. However, salient aspects of collaborative interfaces, and computer assisted diagnostic (CAD) tools are yet to be integrated into workflow designs. The Computer Assisted Diagnostics and Interventions (CADI) group at the University at Buffalo has developed an architecture that facilitates web-enabled use of CAD tools, along with the novel concept of synchronized collaboration. The architecture can support multiple teleradiology applications and case studies are presented here.

Driving chiral domain walls in antiferromagnets using rotating magnetic fields

NASA Astrophysics Data System (ADS)

Pan, Keming; Xing, Lingdi; Yuan, H. Y.; Wang, Weiwei

2018-05-01

We show theoretically and numerically that an antiferromagnetic domain wall can be moved by a rotating magnetic field in the presence of Dzyaloshinskii-Moriya interaction (DMI). Two motion modes are found: rigid domain wall motion at low frequency (corresponding to the perfect frequency synchronization) and the oscillating motion at high frequency. In the full synchronized region, the steady velocity of the domain wall is universal, in the sense that it depends only on the frequency of the rotating field and the ratio between DMI strength and exchange constant. The domain wall velocity is independent of the Gilbert damping and the rotating field strength. Moreover, a rotating field in megahertz is sufficient to move the antiferromagnetic domain wall.

Anchoring in a novel bimanual coordination pattern.

PubMed

Maslovat, Dana; Lam, Melanie Y; Brunke, Kirstin M; Chua, Romeo; Franks, Ian M

2009-02-01

Anchoring in cyclical movements has been defined as regions of reduced spatial or temporal variability [Beek, P. J. (1989). Juggling dynamics. PhD thesis. Amsterdam: Free University Press] that are typically found at movement reversal points. For in-phase and anti-phase movements, synchronizing reversal points with a metronome pulse has resulted in decreased anchor point variability and increased pattern stability [Byblow, W. D., Carson, R. G., & Goodman, D. (1994). Expressions of asymmetries and anchoring in bimanual coordination. Human Movement Science, 13, 3-28; Fink, P. W., Foo, P., Jirsa, V. K., & Kelso, J. A. S. (2000). Local and global stabilization of coordination by sensory information. Experimental Brain Research, 134, 9-20]. The present experiment examined anchoring during acquisition, retention, and transfer of a 90 degrees phase-offset continuous bimanual coordination pattern (whereby the right limb lags the left limb by one quarter cycle), involving horizontal flexion about the elbow. Three metronome synchronization strategies were imposed: participants either synchronized maximal flexion of the right arm (i.e., single metronome), both flexion and extension of the right arm (i.e., double metronome within-limb), or flexion of each arm (i.e., double metronome between-limb) to an auditory metronome. In contrast to simpler in-phase and anti-phase movements, synchronization of additional reversal points to the metronome did not reduce reversal point variability or increase pattern stability. Furthermore, practicing under different metronome synchronization strategies did not appear to have a significant effect on the rate of acquisition of the pattern.

A New On-Line Diagnosis Protocol for the SPIDER Family of Byzantine Fault Tolerant Architectures

NASA Technical Reports Server (NTRS)

Geser, Alfons; Miner, Paul S.

2004-01-01

This paper presents the formal verification of a new protocol for online distributed diagnosis for the SPIDER family of architectures. An instance of the Scalable Processor-Independent Design for Electromagnetic Resilience (SPIDER) architecture consists of a collection of processing elements communicating over a Reliable Optical Bus (ROBUS). The ROBUS is a specialized fault-tolerant device that guarantees Interactive Consistency, Distributed Diagnosis (Group Membership), and Synchronization in the presence of a bounded number of physical faults. Formal verification of the original SPIDER diagnosis protocol provided a detailed understanding that led to the discovery of a significantly more efficient protocol. The original protocol was adapted from the formally verified protocol used in the MAFT architecture. It required O(N) message exchanges per defendant to correctly diagnose failures in a system with N nodes. The new protocol achieves the same diagnostic fidelity, but only requires O(1) exchanges per defendant. This paper presents this new diagnosis protocol and a formal proof of its correctness using PVS.

OAM-labeled free-space optical flow routing.

PubMed

Gao, Shecheng; Lei, Ting; Li, Yangjin; Yuan, Yangsheng; Xie, Zhenwei; Li, Zhaohui; Yuan, Xiaocong

2016-09-19

Space-division multiplexing allows unprecedented scaling of bandwidth density for optical communication. Routing spatial channels among transmission ports is critical for future scalable optical network, however, there is still no characteristic parameter to label the overlapped optical carriers. Here we propose a free-space optical flow routing (OFR) scheme by using optical orbital angular moment (OAM) states to label optical flows and simultaneously steer each flow according to their OAM states. With an OAM multiplexer and a reconfigurable OAM demultiplexer, massive individual optical flows can be routed to the demanded optical ports. In the routing process, the OAM beams act as data carriers at the same time their topological charges act as each carrier's labels. Using this scheme, we experimentally demonstrate switching, multicasting and filtering network functions by simultaneously steer 10 input optical flows on demand to 10 output ports. The demonstration of data-carrying OFR with nonreturn-to-zero signals shows that this process enables synchronous processing of massive spatial channels and flexible optical network.

Application of neural based estimation algorithm for gait phases of above knee prosthesis.

PubMed

Tileylioğlu, E; Yilmaz, A

2015-01-01

In this study, two gait phase estimation methods which utilize a rule based quantization and an artificial neural network model respectively are developed and applied for the microcontroller based semi-active knee prosthesis in order to respond user demands and adapt environmental conditions. In this context, an experimental environment in which gait data collected synchronously from both inertial and image based measurement systems has been set up. The inertial measurement system that incorporates MEM accelerometers and gyroscopes is used to perform direct motion measurement through the microcontroller, while the image based measurement system is employed for producing the verification data and assessing the success of the prosthesis. Embedded algorithms dynamically normalize the input data prior to gait phase estimation. The real time analyses of two methods revealed that embedded ANN based approach performs slightly better in comparison with the rule based algorithm and has advantage of being easily-scalable, thus able to accommodate additional input parameters considering the microcontroller constraints.

Realistic Data-Driven Traffic Flow Animation Using Texture Synthesis.

PubMed

Chao, Qianwen; Deng, Zhigang; Ren, Jiaping; Ye, Qianqian; Jin, Xiaogang

2018-02-01

We present a novel data-driven approach to populate virtual road networks with realistic traffic flows. Specifically, given a limited set of vehicle trajectories as the input samples, our approach first synthesizes a large set of vehicle trajectories. By taking the spatio-temporal information of traffic flows as a 2D texture, the generation of new traffic flows can be formulated as a texture synthesis process, which is solved by minimizing a newly developed traffic texture energy. The synthesized output captures the spatio-temporal dynamics of the input traffic flows, and the vehicle interactions in it strictly follow traffic rules. After that, we position the synthesized vehicle trajectory data to virtual road networks using a cage-based registration scheme, where a few traffic-specific constraints are enforced to maintain each vehicle's original spatial location and synchronize its motion in concert with its neighboring vehicles. Our approach is intuitive to control and scalable to the complexity of virtual road networks. We validated our approach through many experiments and paired comparison user studies.

Autonomous smart sensor network for full-scale structural health monitoring

NASA Astrophysics Data System (ADS)

Rice, Jennifer A.; Mechitov, Kirill A.; Spencer, B. F., Jr.; Agha, Gul A.

2010-04-01

The demands of aging infrastructure require effective methods for structural monitoring and maintenance. Wireless smart sensor networks offer the ability to enhance structural health monitoring (SHM) practices through the utilization of onboard computation to achieve distributed data management. Such an approach is scalable to the large number of sensor nodes required for high-fidelity modal analysis and damage detection. While smart sensor technology is not new, the number of full-scale SHM applications has been limited. This slow progress is due, in part, to the complex network management issues that arise when moving from a laboratory setting to a full-scale monitoring implementation. This paper presents flexible network management software that enables continuous and autonomous operation of wireless smart sensor networks for full-scale SHM applications. The software components combine sleep/wake cycling for enhanced power management with threshold detection for triggering network wide tasks, such as synchronized sensing or decentralized modal analysis, during periods of critical structural response.

Real-time scalable visual analysis on mobile devices

NASA Astrophysics Data System (ADS)

Pattath, Avin; Ebert, David S.; May, Richard A.; Collins, Timothy F.; Pike, William

2008-02-01

Interactive visual presentation of information can help an analyst gain faster and better insight from data. When combined with situational or context information, visualization on mobile devices is invaluable to in-field responders and investigators. However, several challenges are posed by the form-factor of mobile devices in developing such systems. In this paper, we classify these challenges into two broad categories - issues in general mobile computing and issues specific to visual analysis on mobile devices. Using NetworkVis and Infostar as example systems, we illustrate some of the techniques that we employed to overcome many of the identified challenges. NetworkVis is an OpenVG-based real-time network monitoring and visualization system developed for Windows Mobile devices. Infostar is a flash-based interactive, real-time visualization application intended to provide attendees access to conference information. Linked time-synchronous visualization, stylus/button-based interactivity, vector graphics, overview-context techniques, details-on-demand and statistical information display are some of the highlights of these applications.

High duty cycle inverse Compton scattering X-ray source

DOE PAGES

Ovodenko, A.; Agustsson, R.; Babzien, M.; ...

2016-12-22

Inverse Compton Scattering (ICS) is an emerging compact X-ray source technology, where the small source size and high spectral brightness are of interest for multitude of applications. However, to satisfy the practical flux requirements, a high-repetition-rate ICS system needs to be developed. To this end, this article reports the experimental demonstration of a high peak brightness ICS source operating in a burst mode at 40 MHz. A pulse train interaction has been achieved by recirculating a picosecond CO 2 laser pulse inside an active optical cavity synchronized to the electron beam. The pulse train ICS performance has been characterized atmore » 5- and 15- pulses per train and compared to a single pulse operation under the same operating conditions. Lastly, with the observed near-linear X-ray photon yield gain due to recirculation, as well as noticeably higher operational reliability, the burst-mode ICS offers a great potential for practical scalability towards high duty cycles.« less

Continuous whole-system monitoring toward rapid understanding of production HPC applications and systems

DOE PAGES

Agelastos, Anthony; Allan, Benjamin; Brandt, Jim; ...

2016-05-18

A detailed understanding of HPC applications’ resource needs and their complex interactions with each other and HPC platform resources are critical to achieving scalability and performance. Such understanding has been difficult to achieve because typical application profiling tools do not capture the behaviors of codes under the potentially wide spectrum of actual production conditions and because typical monitoring tools do not capture system resource usage information with high enough fidelity to gain sufficient insight into application performance and demands. In this paper we present both system and application profiling results based on data obtained through synchronized system wide monitoring onmore » a production HPC cluster at Sandia National Laboratories (SNL). We demonstrate analytic and visualization techniques that we are using to characterize application and system resource usage under production conditions for better understanding of application resource needs. Furthermore, our goals are to improve application performance (through understanding application-to-resource mapping and system throughput) and to ensure that future system capabilities match their intended workloads.« less

ROBUS-2: A Fault-Tolerant Broadcast Communication System

NASA Technical Reports Server (NTRS)

Torres-Pomales, Wilfredo; Malekpour, Mahyar R.; Miner, Paul S.

2005-01-01

The Reliable Optical Bus (ROBUS) is the core communication system of the Scalable Processor-Independent Design for Enhanced Reliability (SPIDER), a general-purpose fault-tolerant integrated modular architecture currently under development at NASA Langley Research Center. The ROBUS is a time-division multiple access (TDMA) broadcast communication system with medium access control by means of time-indexed communication schedule. ROBUS-2 is a developmental version of the ROBUS providing guaranteed fault-tolerant services to the attached processing elements (PEs), in the presence of a bounded number of faults. These services include message broadcast (Byzantine Agreement), dynamic communication schedule update, clock synchronization, and distributed diagnosis (group membership). The ROBUS also features fault-tolerant startup and restart capabilities. ROBUS-2 is tolerant to internal as well as PE faults, and incorporates a dynamic self-reconfiguration capability driven by the internal diagnostic system. This version of the ROBUS is intended for laboratory experimentation and demonstrations of the capability to reintegrate failed nodes, dynamically update the communication schedule, and tolerate and recover from correlated transient faults.

Parallel Discrete Molecular Dynamics Simulation With Speculation and In-Order Commitment*†

PubMed Central

Khan, Md. Ashfaquzzaman; Herbordt, Martin C.

2011-01-01

Discrete molecular dynamics simulation (DMD) uses simplified and discretized models enabling simulations to advance by event rather than by timestep. DMD is an instance of discrete event simulation and so is difficult to scale: even in this multi-core era, all reported DMD codes are serial. In this paper we discuss the inherent difficulties of scaling DMD and present our method of parallelizing DMD through event-based decomposition. Our method is microarchitecture inspired: speculative processing of events exposes parallelism, while in-order commitment ensures correctness. We analyze the potential of this parallelization method for shared-memory multiprocessors. Achieving scalability required extensive experimentation with scheduling and synchronization methods to mitigate serialization. The speed-up achieved for a variety of system sizes and complexities is nearly 6× on an 8-core and over 9× on a 12-core processor. We present and verify analytical models that account for the achieved performance as a function of available concurrency and architectural limitations. PMID:21822327

Parallel Discrete Molecular Dynamics Simulation With Speculation and In-Order Commitment.

PubMed

Khan, Md Ashfaquzzaman; Herbordt, Martin C

2011-07-20

Discrete molecular dynamics simulation (DMD) uses simplified and discretized models enabling simulations to advance by event rather than by timestep. DMD is an instance of discrete event simulation and so is difficult to scale: even in this multi-core era, all reported DMD codes are serial. In this paper we discuss the inherent difficulties of scaling DMD and present our method of parallelizing DMD through event-based decomposition. Our method is microarchitecture inspired: speculative processing of events exposes parallelism, while in-order commitment ensures correctness. We analyze the potential of this parallelization method for shared-memory multiprocessors. Achieving scalability required extensive experimentation with scheduling and synchronization methods to mitigate serialization. The speed-up achieved for a variety of system sizes and complexities is nearly 6× on an 8-core and over 9× on a 12-core processor. We present and verify analytical models that account for the achieved performance as a function of available concurrency and architectural limitations.

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

Agelastos, Anthony; Allan, Benjamin; Brandt, Jim

A detailed understanding of HPC applications’ resource needs and their complex interactions with each other and HPC platform resources are critical to achieving scalability and performance. Such understanding has been difficult to achieve because typical application profiling tools do not capture the behaviors of codes under the potentially wide spectrum of actual production conditions and because typical monitoring tools do not capture system resource usage information with high enough fidelity to gain sufficient insight into application performance and demands. In this paper we present both system and application profiling results based on data obtained through synchronized system wide monitoring onmore » a production HPC cluster at Sandia National Laboratories (SNL). We demonstrate analytic and visualization techniques that we are using to characterize application and system resource usage under production conditions for better understanding of application resource needs. Furthermore, our goals are to improve application performance (through understanding application-to-resource mapping and system throughput) and to ensure that future system capabilities match their intended workloads.« less

A Universal and Robust Integrated Platform for the Scalable Production of Human Cardiomyocytes From Pluripotent Stem Cells.

PubMed

Fonoudi, Hananeh; Ansari, Hassan; Abbasalizadeh, Saeed; Larijani, Mehran Rezaei; Kiani, Sahar; Hashemizadeh, Shiva; Zarchi, Ali Sharifi; Bosman, Alexis; Blue, Gillian M; Pahlavan, Sara; Perry, Matthew; Orr, Yishay; Mayorchak, Yaroslav; Vandenberg, Jamie; Talkhabi, Mahmood; Winlaw, David S; Harvey, Richard P; Aghdami, Nasser; Baharvand, Hossein

2015-12-01

Recent advances in the generation of cardiomyocytes (CMs) from human pluripotent stem cells (hPSCs), in conjunction with the promising outcomes from preclinical and clinical studies, have raised new hopes for cardiac cell therapy. We report the development of a scalable, robust, and integrated differentiation platform for large-scale production of hPSC-CM aggregates in a stirred suspension bioreactor as a single-unit operation. Precise modulation of the differentiation process by small molecule activation of WNT signaling, followed by inactivation of transforming growth factor-β and WNT signaling and activation of sonic hedgehog signaling in hPSCs as size-controlled aggregates led to the generation of approximately 100% beating CM spheroids containing virtually pure (∼90%) CMs in 10 days. Moreover, the developed differentiation strategy was universal, as demonstrated by testing multiple hPSC lines (5 human embryonic stem cell and 4 human inducible PSC lines) without cell sorting or selection. The produced hPSC-CMs successfully expressed canonical lineage-specific markers and showed high functionality, as demonstrated by microelectrode array and electrophysiology tests. This robust and universal platform could become a valuable tool for the mass production of functional hPSC-CMs as a prerequisite for realizing their promising potential for therapeutic and industrial applications, including drug discovery and toxicity assays. Recent advances in the generation of cardiomyocytes (CMs) from human pluripotent stem cells (hPSCs) and the development of novel cell therapy strategies using hPSC-CMs (e.g., cardiac patches) in conjunction with promising preclinical and clinical studies, have raised new hopes for patients with end-stage cardiovascular disease, which remains the leading cause of morbidity and mortality globally. In this study, a simplified, scalable, robust, and integrated differentiation platform was developed to generate clinical grade hPSC-CMs as cell aggregates under chemically defined culture conditions. This approach resulted in approximately 100% beating CM spheroids with virtually pure (∼90%) functional cardiomyocytes in 10 days from multiple hPSC lines. This universal and robust bioprocessing platform can provide sufficient numbers of hPSC-CMs for companies developing regenerative medicine technologies to rescue, replace, and help repair damaged heart tissues and for pharmaceutical companies developing advanced biologics and drugs for regeneration of lost heart tissue using high-throughput technologies. It is believed that this technology can expedite clinical progress in these areas to achieve a meaningful impact on improving clinical outcomes, cost of care, and quality of life for those patients disabled and experiencing heart disease. ©AlphaMed Press.

A Universal and Robust Integrated Platform for the Scalable Production of Human Cardiomyocytes From Pluripotent Stem Cells

PubMed Central

Fonoudi, Hananeh; Ansari, Hassan; Abbasalizadeh, Saeed; Larijani, Mehran Rezaei; Kiani, Sahar; Hashemizadeh, Shiva; Zarchi, Ali Sharifi; Bosman, Alexis; Blue, Gillian M.; Pahlavan, Sara; Perry, Matthew; Orr, Yishay; Mayorchak, Yaroslav; Vandenberg, Jamie; Talkhabi, Mahmood; Winlaw, David S.; Harvey, Richard P.; Aghdami, Nasser

2015-01-01

Recent advances in the generation of cardiomyocytes (CMs) from human pluripotent stem cells (hPSCs), in conjunction with the promising outcomes from preclinical and clinical studies, have raised new hopes for cardiac cell therapy. We report the development of a scalable, robust, and integrated differentiation platform for large-scale production of hPSC-CM aggregates in a stirred suspension bioreactor as a single-unit operation. Precise modulation of the differentiation process by small molecule activation of WNT signaling, followed by inactivation of transforming growth factor-β and WNT signaling and activation of sonic hedgehog signaling in hPSCs as size-controlled aggregates led to the generation of approximately 100% beating CM spheroids containing virtually pure (∼90%) CMs in 10 days. Moreover, the developed differentiation strategy was universal, as demonstrated by testing multiple hPSC lines (5 human embryonic stem cell and 4 human inducible PSC lines) without cell sorting or selection. The produced hPSC-CMs successfully expressed canonical lineage-specific markers and showed high functionality, as demonstrated by microelectrode array and electrophysiology tests. This robust and universal platform could become a valuable tool for the mass production of functional hPSC-CMs as a prerequisite for realizing their promising potential for therapeutic and industrial applications, including drug discovery and toxicity assays. Significance Recent advances in the generation of cardiomyocytes (CMs) from human pluripotent stem cells (hPSCs) and the development of novel cell therapy strategies using hPSC-CMs (e.g., cardiac patches) in conjunction with promising preclinical and clinical studies, have raised new hopes for patients with end-stage cardiovascular disease, which remains the leading cause of morbidity and mortality globally. In this study, a simplified, scalable, robust, and integrated differentiation platform was developed to generate clinical grade hPSC-CMs as cell aggregates under chemically defined culture conditions. This approach resulted in approximately 100% beating CM spheroids with virtually pure (∼90%) functional cardiomyocytes in 10 days from multiple hPSC lines. This universal and robust bioprocessing platform can provide sufficient numbers of hPSC-CMs for companies developing regenerative medicine technologies to rescue, replace, and help repair damaged heart tissues and for pharmaceutical companies developing advanced biologics and drugs for regeneration of lost heart tissue using high-throughput technologies. It is believed that this technology can expedite clinical progress in these areas to achieve a meaningful impact on improving clinical outcomes, cost of care, and quality of life for those patients disabled and experiencing heart disease. PMID:26511653

Dynamic full-scalability conversion in scalable video coding

NASA Astrophysics Data System (ADS)

Lee, Dong Su; Bae, Tae Meon; Thang, Truong Cong; Ro, Yong Man

2007-02-01

For outstanding coding efficiency with scalability functions, SVC (Scalable Video Coding) is being standardized. SVC can support spatial, temporal and SNR scalability and these scalabilities are useful to provide a smooth video streaming service even in a time varying network such as a mobile environment. But current SVC is insufficient to support dynamic video conversion with scalability, thereby the adaptation of bitrate to meet a fluctuating network condition is limited. In this paper, we propose dynamic full-scalability conversion methods for QoS adaptive video streaming in SVC. To accomplish full scalability dynamic conversion, we develop corresponding bitstream extraction, encoding and decoding schemes. At the encoder, we insert the IDR NAL periodically to solve the problems of spatial scalability conversion. At the extractor, we analyze the SVC bitstream to get the information which enable dynamic extraction. Real time extraction is achieved by using this information. Finally, we develop the decoder so that it can manage the changing scalability. Experimental results showed that dynamic full-scalability conversion was verified and it was necessary for time varying network condition.

Gender and autistic traits modulate implicit motor synchrony

PubMed Central

Cheng, Miao; Kato, Masaharu

2017-01-01

Interpersonal motor synchrony during walking or dancing is universally observed across cultures, and this joint movement was modulated by physical and social parameters. However, human interactions are greatly shaped by our unique traits, and self-related factors are surprisingly little studied in the context of interpersonal motor synchrony. In this study, we investigated two such factors known to be highly associated with motor coordination: gender and autistic traits. We employed a real-world task extending our understanding beyond laboratory tasks. Participants of the same gender were paired up to walk and chat in a natural environment. A cover story was introduced so that participants would not know their walking steps were being recorded and instead believed that their location was being tracked by a global positioning system (GPS), so they would ignore the motor recording. We found that the female pairs’ steps were more synchronized than those of the males, and higher autistic tendencies (measured by the autism-spectrum quotient) attenuated synchronous steps. Those who synchronized better had higher impression rating increase for their walking partners (measured by interpersonal judgement scale) than those who synchronized less well. Our results indicated that the participants’ joint movements were shaped by predisposed traits and might share similar mechanism with social functions such as empathy. PMID:28873419

Synchronisms and correlations of spring phenology between apical and lateral meristems in two boreal conifers.

PubMed

Antonucci, Serena; Rossi, Sergio; Deslauriers, Annie; Lombardi, Fabio; Marchetti, Marco; Tognetti, Roberto

2015-10-01

Phenological synchronisms between apical and lateral meristems could clarify some aspects related to the physiological relationships among the different organs of trees. This study correlated the phenological phases of bud development and xylem differentiation during spring 2010-14 in balsam fir (Abies balsamea Mill.) and black spruce [(Picea mariana Mill. (BSP)] of the Monts-Valin National Park (Quebec, Canada) by testing the hypothesis that bud development occurs after the reactivation of xylem growth. From May to September, we conducted weekly monitoring of xylem differentiation using microcores and bud development with direct observations on terminal branches. Synchronism between the beginning of bud development and xylem differentiation was found in both species with significant correlations between the phases of bud and xylem phenology. Degree-day sum was more appropriate in assessing the date of bud growth resumption, while thermal thresholds were more suitable for cambium phenology. Our results provide new knowledge on the dynamics of spring phenology and novel information on the synchronisms between two meristems in coniferous trees. The study demonstrates the importance of precisely defining the phases of bud development in order to correctly analyse the relationships with xylem phenology. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Role of the dorsal premotor cortex in rhythmic auditory-motor entrainment: a perturbational approach by rTMS.

PubMed

Giovannelli, Fabio; Innocenti, Iglis; Rossi, Simone; Borgheresi, Alessandra; Ragazzoni, Aldo; Zaccara, Gaetano; Viggiano, Maria Pia; Cincotta, Massimo

2014-04-01

Synchronization of body movements to an external beat is a universal human ability, which has also been recently documented in nonhuman species. The neural substrates of this rhythmic motor entrainment are still under investigation. Correlational neuroimaging data suggest an involvement of the dorsal premotor cortex (dPMC) and the supplementary motor area (SMA). In 14 healthy volunteers, we more specifically investigated the neural network underlying this phenomenon using a causal approach by an established 1-Hz repetitive transcranial magnetic stimulation (rTMS) protocol, which produces a focal suppression of cortical excitability outlasting the stimulation period. Synchronization accuracy between rhythmic cues and right index finger tapping, as measured by the mean time lag (asynchrony) between motor and auditory events, was significantly affected when the right dPMC function was transiently perturbed by "off-line" focal rTMS, whereas the reproduction of the rhythmic sequence per se (inter-tap-interval) was spared. This approach affected metrical rhythms of different complexity, but not non-metrical or isochronous sequences. Conversely, no change in auditory-motor synchronization was observed with rTMS of the SMA, of the left dPMC or over a control site (midline occipital area). Our data strongly support the view that the right dPMC is crucial for rhythmic auditory-motor synchronization in humans.

Ultra-Scalable Algorithms for Large-Scale Uncertainty Quantification in Inverse Wave Propagation

DTIC Science & Technology

2016-03-04

53] N. Petra , J. Martin , G. Stadler, and O. Ghattas, A computational framework for infinite-dimensional Bayesian inverse problems: Part II...positions: Alen Alexanderian (NC State), Tan Bui-Thanh (UT-Austin), Carsten Burstedde (University of Bonn), Noemi Petra (UC Merced), Georg Stalder (NYU), Hari...Baltimore, MD, Nov. 2002. SC2002 Best Technical Paper Award. [3] A. Alexanderian, N. Petra , G. Stadler, and O. Ghattas, A-optimal design of exper

ESRDC - Designing and Powering the Future Fleet

DTIC Science & Technology

2018-02-22

Awards Management 301 Main Street University of South Carolina Columbia, SC 29208 1600 Hampton St, Suite 414 Phone: 803-777-7890 Columbia, SC 29208... managing short circuit faults in MVDC Systems, and 5) modeling of SiC-based electronic power converters to support accurate scalable models in S3D...Research in advanced thermal management followed three tracks. We developed models of thermal system components that are suitable for use in early stage

Validation of 3D RANS-SA Calculations on Strand/Cartesian Meshes

DTIC Science & Technology

2014-01-07

a parallel environment. This allows for significant gains in efficiency and scalability of domain connectiv- ity, effectively eliminating inter... equation of state , p = ρRT is used to close the equations . 4 of 22 American Institute of Aeronautics and Astronautics 6 III.A. Discretization and...Utah State University 1415 Old Main Hill - Room 64 Logan, UT 84322 -1415 1 ABSTRACT Validation of 3D RANS-SA Calculations on Strand/Cartesian Meshes

Epitaxial Growth of Molecular Crystals on van der Waals Substrates for High-Performance Organic Electronics

DTIC Science & Technology

2014-01-01

Taniguchi Advanced Materials Laboratory National Institute for Materials Science 1–1 Namiki, Tsukuba , 305–0044 , Japan Prof. J. Hone Department...of Mechanical Engineering Columbia University New York , NY , 10027 , USA DOI : 10.1002/adma.201304973 The growth of high-quality organic...vdW heterostructures, combined with recent progress on large-area growth of layered materials , [ 6,7 ] provides new opportunities for the scalable

Departures from the Friedmann-Lemaitre-Robertston-Walker Cosmological Model in an Inhomogeneous Universe: A Numerical Examination.

PubMed

Giblin, John T; Mertens, James B; Starkman, Glenn D

2016-06-24

While the use of numerical general relativity for modeling astrophysical phenomena and compact objects is commonplace, the application to cosmological scenarios is only just beginning. Here, we examine the expansion of a spacetime using the Baumgarte-Shapiro-Shibata-Nakamura formalism of numerical relativity in synchronous gauge. This work represents the first numerical cosmological study that is fully relativistic, nonlinear, and without symmetry. The universe that emerges exhibits an average Friedmann-Lemaître-Robertson-Walker (FLRW) behavior; however, this universe also exhibits locally inhomogeneous expansion beyond that expected in linear perturbation theory around a FLRW background.

Clock distribution for BaF2 readout electronics at CSNS-WNS

NASA Astrophysics Data System (ADS)

He, Bing; Cao, Ping; Zhang, De-Liang; Wang, Qi; Zhang, Ya-Xi; Qi, Xin-Cheng; An, Qi

2017-01-01

A BaF2 (Barium Fluoride) detector array is designed to precisely measure the (n, γ) cross section at the CSNS-WNS (white neutron source at China Spallation Neutron Source). It is a 4π solid angle-shaped detector array consisting of 92 BaF2 crystal elements. To discriminate signals from the BaF2 detector, a pulse shape discrimination method is used, supported by a waveform digitization technique. There are 92 channels for digitizing. The precision and synchronization of clock distribution restricts the performance of waveform digitizing. In this paper, a clock prototype for the BaF2 readout electronics at CSNS-WNS is introduced. It is based on the PXIe platform and has a twin-stage tree topology. In the first stage, clock is synchronously distributed from the tree root to each PXIe crate through a coaxial cable over a long distance, while in the second stage, the clock is further distributed to each electronic module through a PXIe dedicated differential star bus. With the help of this topology, each tree node can fan out up to 20 clocks with 3U size. Test results show the clock jitter is less than 20 ps, which meets the requirements of the BaF2 readout electronics. Besides, this clock system has the advantages of high density, simplicity, scalability and cost saving, so it can be useful for other clock distribution applications. Supported by National Research and Development plan (2016 YFA0401602) NSAF (U1530111) and National Natural Science Foundation of China (11005107)

Injection locking of optomechanical oscillators via acoustic waves.

PubMed

Huang, Ke; Hossein-Zadeh, Mani

2018-04-02

Injection locking is an effective technique for synchronization of oscillator networks and controlling the phase and frequency of individual oscillators. As such, exploring new mechanisms for injection locking of emerging oscillators is important for their usage in various systems. Here, we present the first demonstration of injection locking of a radiation pressure driven optomechanical oscillator (OMO) via acoustic waves. As opposed to previously reported techniques (based on pump modulation or direct application of a modulated electrostatic force), injection locking of OMO via acoustic waves does not require optical power modulation or physical contact with the OMO and it can be easily implemented on various platforms to lock different types of OMOs independent of their size and structure. Using this approach we have locked the phase and frequency of two distinct modes of a microtoroidal silica OMO to a piezoelectric transducer (PZT). We have characterized the behavior of the injection locked OMO with three acoustic excitation configurations and showed that even without proper acoustic impedance, matching the OMO can be locked to the PZT and tuned over 17 kHz with only -30 dBm of RF power fed to the PZT. The high efficiency, simplicity, and scalability of the proposed approach paves the road toward a new class of photonic systems that rely on synchronization of several OMOs to a single or multiple RF oscillators with applications in optical communication, metrology, and sensing. Beyond its practical applications, injection locking via acoustic waves can be used in fundamental studies in quantum optomechanics where thermal and optical isolation of the OMO are critical.

Etude et simulation du protocole TTEthernet sur un sous-systeme de gestion de vols et adaptation de la planification des tâches a des fins de simulation

NASA Astrophysics Data System (ADS)

Abidi, Dhafer

TTEthernet is a deterministic network technology that makes enhancements to Layer 2 Quality-of-Service (QoS) for Ethernet. The components that implement its services enrich the Ethernet functionality with distributed fault-tolerant synchronization, robust temporal partitioning bandwidth and synchronous communication with fixed latency and low jitter. TTEthernet services can facilitate the design of scalable, robust, less complex distributed systems and architectures tolerant to faults. Simulation is nowadays an essential step in critical systems design process and represents a valuable support for validation and performance evaluation. CoRE4INET is a project bringing together all TTEthernet simulation models currently available. It is based on the extension of models of OMNeT ++ INET framework. Our objective is to study and simulate the TTEthernet protocol on a flight management subsystem (FMS). The idea is to use CoRE4INET to design the simulation model of the target system. The problem is that CoRE4INET does not offer a task scheduling tool for TTEthernet network. To overcome this problem we propose an adaptation for simulation purposes of a task scheduling approach based on formal specification of network constraints. The use of Yices solver allowed the translation of the formal specification into an executable program to generate the desired transmission plan. A case study allowed us at the end to assess the impact of the arrangement of Time-Triggered frames offsets on the performance of each type of the system traffic.

Let's Get Virtual: Observing Physical Education Field Experiences through Synchronous Video Conferencing

ERIC Educational Resources Information Center

Krause, Jennifer M.; Douglas, Scott; Lynch, Brandy M.; Kesselring, LeAnn

2018-01-01

The student-teaching experience is the most noteworthy experience for a teacher candidate (TC) in a teacher preparation program. University supervisors play a crucial role in this experience through feedback, support and maintaining congruency between the student teaching environment and the teacher preparation program. Due to issues related to…

Designing Online Tutor Training for Language Courses: A Case Study

ERIC Educational Resources Information Center

Stickler, Ursula; Hampel, Regine

2007-01-01

In 2003-04 the Open University offered its first German beginners' course with a dual tuition strand: tutorials were delivered either face-to-face or online using synchronous, audio-graphic, Internet-based conferencing software. For the new online tutors, a special training programme was designed and delivered. We evaluated the benefits of our…

Expanding the Traditional Physiology Class with Asynchronous Online Discussions and Collaborative Projects

ERIC Educational Resources Information Center

Taradi, Suncana Kukolja; Taradi, Milan

2004-01-01

Discussion and writing are very powerful ways to support learning. This article describes the use of a free, synchronous online forum to expand student-teacher discussions beyond the time/place constraints of the physical physiology classroom. The main participants were medical students enrolled in physiology class at the University of Zagreb…

Facilitating Professional Learning Communities among Higher Education Faculty: The Walden Junto Model

ERIC Educational Resources Information Center

Bedford, Laurie A.; Rossow, Katie A.

2017-01-01

Virtual Professional Learning Communities (PLC) have become an innovative way to meet the professional development needs of faculty in the online learning environment. Walden University's model for PLCs, the Walden Junto, uses a combination of synchronous and asynchronous online strategies and is based on a philosophy that embraces the faculty…

Meeting Face to Face = Seeing Eye to Eye?: Interglobal Dialogue via Videoconference

ERIC Educational Resources Information Center

Kan, Koon Hwee

2011-01-01

Based on a series of videoconferences held between two universities, one located in China and another in the United States, this pilot curriculum study illustrates how successful interglobal communication via synchronized educational technology requires detailed planning and the use of a substantial number of pedagogical strategies. Achieving the…

Evaluating the Quality of a Chat Service

ERIC Educational Resources Information Center

Arnold, Julie; Kaske, Neal K.

2005-01-01

A quantitative study of a university chat reference service (online synchronous) addresses the following research questions: (1) What types of questions are being asked? (2) Who is asking the questions of the service? and (3) Did the customers get correct answers to their questions? All the transcripts (351) from January through August 2002 were…

An Undergraduate Survey Course on Asynchronous Sequential Logic, Ladder Logic, and Fuzzy Logic

ERIC Educational Resources Information Center

Foster, D. L.

2012-01-01

For a basic foundation in computer engineering, universities traditionally teach synchronous sequential circuit design, using discrete gates or field programmable gate arrays, and a microcomputers course that includes basic I/O processing. These courses, though critical, expose students to only a small subset of tools. At co-op schools like…

Blended Learning for Learner Empowerment: Voices from the Middle East

ERIC Educational Resources Information Center

Tamim, Rana M.

2018-01-01

Blended learning (BL) is still in its infancy in the United Arab Emirates, but is gaining growing attention and acceptance. The particular university under investigation offers its nationally accredited graduate programs with a BL format that makes use of synchronous virtual classrooms, asynchronous self-study, and face-to-face sessions. The…

Breaking out of the Asynchronous Box: Using Web Conferencing in Distance Learning

ERIC Educational Resources Information Center

Lietzau, Julie Arnold; Mann, Barbara J.

2009-01-01

A discussion of a university library's use of Web conferencing (real-time synchronous instruction) which addresses the questions (1) Is Web conferencing a viable option for distance students in online only classrooms? (2) Do faculty and students benefit from this type of instruction? Four different scenarios are presented with assessment results…

Experiences of Instructors in Online Learning Environments: Identifying and Regulating Emotions

ERIC Educational Resources Information Center

Regan, Kelley; Evmenova, Anna; Baker, Pam; Jerome, Marci Kinas; Spencer, Vicky; Lawson, Holly; Werner, Terry

2012-01-01

In an effort to expand existing research on the barriers of instructors experience in online learning environments (OLEs), a qualitative study was conducted at a large mid-Atlantic university. Six instructors teaching in different OLE formats (e.g., asynchronous, hybrid, and synchronous via videoconferencing) participated in two focus groups in…

An Assistive Computerized Learning Environment for Distance Learning Students with Learning Disabilities

ERIC Educational Resources Information Center

Klemes, Joel; Epstein, Alit; Zuker, Michal; Grinberg, Nira; Ilovitch, Tamar

2006-01-01

The current study examines how a computerized learning environment assists students with learning disabilities (LD) enrolled in a distance learning course at the Open University of Israel. The technology provides computer display of the text, synchronized with auditory output and accompanied by additional computerized study skill tools which…

Workplace Literacy for World Class Manufacturing. Final Report.

ERIC Educational Resources Information Center

Dowling, William D.; And Others

The Ohio State University, Inland Fisher Guide Division of General Motors, and United Auto Workers Local 969 formed a collaborative partnership in 1990 to train employees whose inadequate literacy skills made them unable to respond to the requirements of "synchronous manufacturing" (or "just in time" production). One of the goals is to reduce the…

Universal filtered multi-carrier system for asynchronous uplink transmission in optical access network

NASA Astrophysics Data System (ADS)

Kang, Soo-Min; Kim, Chang-Hun; Han, Sang-Kook

2016-02-01

In passive optical network (PON), orthogonal frequency division multiplexing (OFDM) has been studied actively due to its advantages such as high spectra efficiency (SE), dynamic resource allocation in time or frequency domain, and dispersion robustness. However, orthogonal frequency division multiple access (OFDMA)-PON requires tight synchronization among multiple access signals. If not, frequency orthogonality could not be maintained. Also its sidelobe causes inter-channel interference (ICI) to adjacent channel. To prevent ICI caused by high sidelobes, guard band (GB) is usually used which degrades SE. Thus, OFDMA-PON is not suitable for asynchronous uplink transmission in optical access network. In this paper, we propose intensity modulation/direct detection (IM/DD) based universal filtered multi-carrier (UFMC) PON for asynchronous multiple access. The UFMC uses subband filtering to subsets of subcarriers. Since it reduces sidelobe of each subband by applying subband filtering, it could achieve better performance compared to OFDM. For the experimental demonstration, different sample delay was applied to subbands to implement asynchronous transmission condition. As a result, time synchronization robustness of UFMC was verified in asynchronous multiple access system.

Subthalamic stimulation modulates cortical motor network activity and synchronization in Parkinson's disease.

PubMed

Weiss, Daniel; Klotz, Rosa; Govindan, Rathinaswamy B; Scholten, Marlieke; Naros, Georgios; Ramos-Murguialday, Ander; Bunjes, Friedemann; Meisner, Christoph; Plewnia, Christian; Krüger, Rejko; Gharabaghi, Alireza

2015-03-01

Dynamic modulations of large-scale network activity and synchronization are inherent to a broad spectrum of cognitive processes and are disturbed in neuropsychiatric conditions including Parkinson's disease. Here, we set out to address the motor network activity and synchronization in Parkinson's disease and its modulation with subthalamic stimulation. To this end, 20 patients with idiopathic Parkinson's disease with subthalamic nucleus stimulation were analysed on externally cued right hand finger movements with 1.5-s interstimulus interval. Simultaneous recordings were obtained from electromyography on antagonistic muscles (right flexor digitorum and extensor digitorum) together with 64-channel electroencephalography. Time-frequency event-related spectral perturbations were assessed to determine cortical and muscular activity. Next, cross-spectra in the time-frequency domain were analysed to explore the cortico-cortical synchronization. The time-frequency modulations enabled us to select a time-frequency range relevant for motor processing. On these time-frequency windows, we developed an extension of the phase synchronization index to quantify the global cortico-cortical synchronization and to obtain topographic differentiations of distinct electrode sites with respect to their contributions to the global phase synchronization index. The spectral measures were used to predict clinical and reaction time outcome using regression analysis. We found that movement-related desynchronization of cortical activity in the upper alpha and beta range was significantly facilitated with 'stimulation on' compared to 'stimulation off' on electrodes over the bilateral parietal, sensorimotor, premotor, supplementary-motor, and prefrontal areas, including the bilateral inferior prefrontal areas. These spectral modulations enabled us to predict both clinical and reaction time improvement from subthalamic stimulation. With 'stimulation on', interhemispheric cortico-cortical coherence in the beta band was significantly attenuated over the bilateral sensorimotor areas. Similarly, the global cortico-cortical phase synchronization was attenuated, and the topographic differentiation revealed stronger desynchronization over the (ipsilateral) right-hemispheric prefrontal, premotor and sensorimotor areas compared to 'stimulation off'. We further demonstrated that the cortico-cortical phase synchronization was largely dominated by genuine neuronal coupling. The clinical improvement with 'stimulation on' compared to 'stimulation off' could be predicted from this cortical decoupling with multiple regressions, and the reduction of synchronization over the right prefrontal area showed a linear univariate correlation with clinical improvement. Our study demonstrates wide-spread activity and synchronization modulations of the cortical motor network, and highlights subthalamic stimulation as a network-modulating therapy. Accordingly, subthalamic stimulation may release bilateral cortical computational resources by facilitating movement-related desynchronization. Moreover, the subthalamic nucleus is critical to balance inhibitory and facilitatory cortical players within the motor program. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Ultradian metronome: timekeeper for orchestration of cellular coherence.

PubMed

Lloyd, David; Murray, Douglas B

2005-07-01

Dynamic intracellular spatial and temporal organization emerges from spontaneous synchronization of a massive array of weakly coupled oscillators; the majority of subcellular processes are implicated in this integrated expression of cellular physiology. Evidence for this view comes mainly from studies of Saccharomyces cerevisiae growing in self-synchronized continuous cultures, in which a temperature-compensated ultradian clock (period of approximately 40 min) couples fermentation with redox state in addition to the transcriptome and cell-division-cycle progression. Functions for ultradian clocks have also been determined in other yeasts (e.g. Schizosaccharomyces pombe and Candida utilis), seven protists (e.g. Acanthamoeba castellanii and Paramecium tetraurelia), as well as cultured mammalian cells. We suggest that ultradian timekeeping is a basic universal necessity for coordinated intracellular coherence.

HiDi: an efficient reverse engineering schema for large-scale dynamic regulatory network reconstruction using adaptive differentiation.

PubMed

Deng, Yue; Zenil, Hector; Tegnér, Jesper; Kiani, Narsis A

2017-12-15

The use of differential equations (ODE) is one of the most promising approaches to network inference. The success of ODE-based approaches has, however, been limited, due to the difficulty in estimating parameters and by their lack of scalability. Here, we introduce a novel method and pipeline to reverse engineer gene regulatory networks from gene expression of time series and perturbation data based upon an improvement on the calculation scheme of the derivatives and a pre-filtration step to reduce the number of possible links. The method introduces a linear differential equation model with adaptive numerical differentiation that is scalable to extremely large regulatory networks. We demonstrate the ability of this method to outperform current state-of-the-art methods applied to experimental and synthetic data using test data from the DREAM4 and DREAM5 challenges. Our method displays greater accuracy and scalability. We benchmark the performance of the pipeline with respect to dataset size and levels of noise. We show that the computation time is linear over various network sizes. The Matlab code of the HiDi implementation is available at: www.complexitycalculator.com/HiDiScript.zip. hzenilc@gmail.com or narsis.kiani@ki.se. Supplementary data are available at Bioinformatics online. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Generalized Low-Temperature Fabrication of Scalable Multi-Type Two-Dimensional Nanosheets with a Green Soft Template.

PubMed

Wang, Lanfang; Song, Chuang; Shi, Yi; Dang, Liyun; Jin, Ying; Jiang, Hong; Lu, Qingyi; Gao, Feng

2016-04-11

Two-dimensional nanosheets with high specific surface areas and fascinating physical and chemical properties have attracted tremendous interests because of their promising potentials in both fundamental research and practical applications. However, the problem of developing a universal strategy with a facile and cost-effective synthesis process for multi-type ultrathin 2 D nanostructures remains unresolved. Herein, we report a generalized low-temperature fabrication of scalable multi-type 2 D nanosheets including metal hydroxides (such as Ni(OH)2, Co(OH)2, Cd(OH)2, and Mg(OH)2), metal oxides (such as ZnO and Mn3O4), and layered mixed transition-metal hydroxides (Ni-Co LDH, Ni-Fe LDH, Co-Fe LDH, and Ni-Co-Fe layered ternary hydroxides) through the rational employment of a green soft-template. The synthesized crystalline inorganic nanosheets possess confined thickness, resulting in ultrahigh surface atom ratios and chemically reactive facets. Upon evaluation as electrode materials for pseudocapacitors, the Ni-Co LDH nanosheets exhibit a high specific capacitance of 1087 F g(-1) at a current density of 1 A g(-1), and excellent stability, with 103% retention after 500 cycles. This strategy is facile and scalable for the production of high-quality ultrathin crystalline inorganic nanosheets, with the possibility of extension to the preparation of other complex nanosheets. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Student-Centered Mental Health Virtual Community Needs and Features: A Focus Group Study.

PubMed

El Morr, Christo; Maule, Catherine; Ashfaq, Iqra; Ritvo, Paul; Ahmad, Farah

2017-01-01

Mental health is a pervasive challenge in the population and especially for university/college students on campuses across North America. Anxiety, stress and depression are on the rise and a scalable, economically sound innovation is essential to address these mental health challenges. The research team has conducted 8 focus groups in April to May 2016 in order to elicit perspectives of students at York University about their online activities and the development of an online mindfulness based Mental Health Virtual Community. This paper explains the main results of the qualitative analysis pertaining to the challenges and benefits of an online mindfulness based Mental Health Virtual Community.

Loran-C time management

NASA Technical Reports Server (NTRS)

Justice, Charles; Mason, Norm; Taggart, Doug

1994-01-01

As of 1 Oct. 1993, the US Coast Guard (USCG) supports and operates fifteen Loran-C chains. With the introduction of the Global Positioning Systems (GPS) and the termination of the Department of Defense (DOD) overseas need for Loran-C, the USCG will cease operating the three remaining overseas chains by 31 Dec. 1994. Following this date, the USCG Loran-C system will consist of twelve chains. Since 1971, management of time synchronization of the Loran-C system has been conducted under a Memorandum of Agreement between the US Naval Observatory (USNO) and the USCG. The requirement to maintain synchronization with Coordinated Universal Time (UTC) was initially specified as +/- 25 microseconds. This tolerance was rapidly lowered to +/- 2.5 microseconds in 1974. To manage this synchronization requirement, the USCG incorporated administrative practices which kept the USNO appraised of all aspects of the master timing path. This included procedures for responding to timing path failures, timing adjustments, and time steps. Conducting these aspects of time synchronization depended on message traffic between the various master stations and the USNO. To determine clock adjustment the USCG relied upon the USNO's Series 4 and 100 updates so that the characteristics of the master clock could be plotted and controls appropriately applied. In 1987, Public Law 100-223, under the Airport and Airway Improvement Act Amendment, reduced the synchronization tolerance to approximately 100 nanoseconds for chains serving the National Airspace System (NAS). This action caused changes in the previous administrative procedures and techniques. The actions taken by the USCG to meet the requirements of this law are presented.

Visual interaction: models, systems, prototypes. The Pictorial Computing Laboratory at the University of Rome La Sapienza.

PubMed

Bottoni, Paolo; Cinque, Luigi; De Marsico, Maria; Levialdi, Stefano; Panizzi, Emanuele

2006-06-01

This paper reports on the research activities performed by the Pictorial Computing Laboratory at the University of Rome, La Sapienza, during the last 5 years. Such work, essentially is based on the study of humancomputer interaction, spans from metamodels of interaction down to prototypes of interactive systems for both synchronous multimedia communication and groupwork, annotation systems for web pages, also encompassing theoretical and practical issues of visual languages and environments also including pattern recognition algorithms. Some applications are also considered like e-learning and collaborative work.

A Scalable Fabrication Process for Liquid Crystal Based Uncooled Thermal Imagers

DTIC Science & Technology

2016-02-12

ll.mit.edu). Phillip Bos, Valerie Finnemeyer, Colin McGinty and Douglas Bryant are with the Liquid Crystal Institute at Kent State University, Kent...Crystal-Based Uncooled Thermal Imagers Shaun Berry, Carl Bozler, Robert Reich, Harry Clark Jr., Phillip Bos, Valerie Finnemeyer, Colin McGinty...was aligned to the die features on the wafer with appropriate weight added (Fig. 5b). We used stainless steel bars to apply the weight to the block

High Optical Access Trap 2.0.

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

Maunz, Peter Lukas Wilhelm

2016-01-26

The High Optical Access (HOA) trap was designed in collaboration with the Modular Universal Scalable Ion-trap Quantum Computer (MUSIQC) team, funded along with Sandia National Laboratories through IARPA's Multi Qubit Coherent Operations (MQCO) program. The design of version 1 of the HOA trap was completed in September 2012 and initial devices were completed and packaged in February 2013. The second version of the High Optical Access Trap (HOA-2) was completed in September 2014 and is available at IARPA's disposal.

Scalable Collaborative Infrastructure for a Learning Healthcare System (SCILHS): architecture.

PubMed

Mandl, Kenneth D; Kohane, Isaac S; McFadden, Douglas; Weber, Griffin M; Natter, Marc; Mandel, Joshua; Schneeweiss, Sebastian; Weiler, Sarah; Klann, Jeffrey G; Bickel, Jonathan; Adams, William G; Ge, Yaorong; Zhou, Xiaobo; Perkins, James; Marsolo, Keith; Bernstam, Elmer; Showalter, John; Quarshie, Alexander; Ofili, Elizabeth; Hripcsak, George; Murphy, Shawn N

2014-01-01

We describe the architecture of the Patient Centered Outcomes Research Institute (PCORI) funded Scalable Collaborative Infrastructure for a Learning Healthcare System (SCILHS, http://www.SCILHS.org) clinical data research network, which leverages the $48 billion dollar federal investment in health information technology (IT) to enable a queryable semantic data model across 10 health systems covering more than 8 million patients, plugging universally into the point of care, generating evidence and discovery, and thereby enabling clinician and patient participation in research during the patient encounter. Central to the success of SCILHS is development of innovative 'apps' to improve PCOR research methods and capacitate point of care functions such as consent, enrollment, randomization, and outreach for patient-reported outcomes. SCILHS adapts and extends an existing national research network formed on an advanced IT infrastructure built with open source, free, modular components. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

DNA-programmable multiplexing for scalable, renewable redox protein bio-nanoelectronics.

PubMed

Withey, Gary D; Kim, Jin Ho; Xu, Jimmy

2008-11-01

A universal, site-addressable DNA linking strategy is deployed for the programmable assembly of multifunctional, long-lasting redox protein nanoelectronic devices. This addressable linker, the first incorporated into a redox enzyme-nanoelectronic system, promotes versatility and renewability by allowing the reconfiguration and replacement of enzymes at will. The linker is transferable to all redox proteins due to the simple conjugation chemistry involved. The efficacy of this linking strategy is assessed using two model enzymes, glucose oxidase (GOx) and alcohol dehydrogenase (ADH), self-assembled onto separate nanoelectrode regions comprised of a highly ordered carbon nanotube (CNT) array. The sequence-specificity of DNA hybridization provides the means of encoding spatial address to the self-assembling process that conjugates enzymes tagged with single-stranded DNA (ssDNA) to the tips of designated CNTs functionalized with the complementary strands. In this study, we demonstrate the feasibility of multiplexed, scalable, reconfigurable and renewable transduction of redox protein signals by virtue of DNA addressing.

Power System Observation by using Synchronized Phasor Measurements as a Smart Device

NASA Astrophysics Data System (ADS)

Mitani, Yasunori

Phasor Measurement Unit (PMU) is an apparatus which detects the absolute value of phase angle in sinusoidal signal. When more than two units are located distantly apart from each other, and they are synchronized with GPS signal which tells us the information on exact time, it becomes ready to get phase differences between two distant places. Thus, PMU with GPS receiver is applied to the monitoring of AC power system dynamics and usually installed at substations of transmission lines. The states of power network are uniquely determined by the active and reactive power and the magnitude and phase angle of voltage in each node. Among these values the phase angle had not been easily obtained until the scheme of time synchronism with GPS appeared. In this report, the history of GPS and PMU, and the current status of the applications in power systems in the world are presented. In Japan we are developing a power system monitoring system with PMUs installed at University's campuses with 100V outlets, which is called Campus WAMS. This report also introduces some results from the Campus WAMS briefly.

A comprehensive methodology for the multidimensional and synchronic data collecting in soundscape.

PubMed

Kogan, Pablo; Turra, Bruno; Arenas, Jorge P; Hinalaf, María

2017-02-15

The soundscape paradigm is comprised of complex living systems where individuals interact moment-by-moment among one another and with the physical environment. The real environments provide promising conditions to reveal deep soundscape behavior, including the multiple components involved and their interrelations as a whole. However, measuring and analyzing the numerous simultaneous variables of soundscape represents a challenge that is not completely understood. This work proposes and applies a comprehensive methodology for multidimensional and synchronic data collection in soundscape. The soundscape variables were organized into three main entities: experienced environment, acoustic environment, and extra-acoustic environment, containing, in turn, subgroups of variables called components. The variables contained in these components were acquired through synchronic field techniques that include surveys, acoustic measurements, audio recordings, photography, and video. The proposed methodology was tested, optimized, and applied in diverse open environments, including squares, parks, fountains, university campuses, streets, and pedestrian areas. The systematization of this comprehensive methodology provides a framework for soundscape research, a support for urban and environment management, and a preliminary procedure for standardization in soundscape data collecting. Copyright © 2016 Elsevier B.V. All rights reserved.

Random noise can help to improve synchronization of excimer laser pulses.

PubMed

Mingesz, Róbert; Barna, Angéla; Gingl, Zoltán; Mellár, János

2016-02-01

Recently, we have reported on a compact microcontroller-based unit developed to accurately synchronize excimer laser pulses (Mingesz et al. 2012 Fluct. Noise Lett. 11, 1240007 (doi:10.1142/S021947751240007X)). We have shown that dithering based on random jitter noise plus pseudorandom numbers can be used in the digital control system to radically reduce the long-term drift of the laser pulse from the trigger and to improve the accuracy of the synchronization. In this update paper, we present our new experimental results obtained by the use of the delay-controller unit to tune the timing of a KrF excimer laser as an addition to our previous numerical simulation results. The hardware was interfaced to the laser using optical signal paths in order to reduce sensitivity to electromagnetic interference and the control algorithm tested by simulations was applied in the experiments. We have found that the system is able to reduce the delay uncertainty very close to the theoretical limit and performs well in real applications. The simple, compact and flexible system is universal enough to also be used in various multidisciplinary applications.

Mixed H ∞ and Passive Projective Synchronization for Fractional Order Memristor-Based Neural Networks with Time-Delay and Parameter Uncertainty

NASA Astrophysics Data System (ADS)

Song, Xiao-Na; Song, Shuai; Tejado Balsera, Inés; Liu, Lei-Po

2017-10-01

This paper investigates the mixed H ∞ and passive projective synchronization problem for fractional-order (FO) memristor-based neural networks. Our aim is to design a controller such that, though the unavoidable phenomena of time-delay and parameter uncertainty are fully considered, the resulting closed-loop system is asymptotically stable with a mixed H ∞ and passive performance level. By combining active and adaptive control methods, a novel hybrid control strategy is designed, which can guarantee the robust stability of the closed-loop system and also ensure a mixed H ∞ and passive performance level. Via the application of FO Lyapunov stability theory, the projective synchronization conditions are addressed in terms of linear matrix inequality techniques. Finally, two simulation examples are given to illustrate the effectiveness of the proposed method. Supported by National Natural Science Foundation of China under Grant Nos. U1604146, U1404610, 61473115, 61203047, Science and Technology Research Project in Henan Province under Grant Nos. 152102210273, 162102410024, and Foundation for the University Technological Innovative Talents of Henan Province under Grant No. 18HASTIT019

An Exploration of Asynchronous and Synchronous Feedback Modes in EFL Writing

ERIC Educational Resources Information Center

Shang, Hui-Fang

2017-01-01

In the English as a foreign language (EFL) writing context, most of the research studies on the feedback process are conducted in a face-to-face context and few research studies have been conducted to investigate what actually happens in online feedback conditions. Thus, this study aimed to compare 44 EFL university students' experience of…

Language Learning Going Global: Linking Teachers and Learners via Commercial Skype-Based CMC

ERIC Educational Resources Information Center

Terhune, N. M.

2016-01-01

This paper reports on students' use of face-to-face synchronous computer-mediated communication (CMC) for oral language learning. It describes a university English language class designed to prepare students for overseas study in which a Skype-based English conversation school was piloted. The study offers analysis of how students used the CMC…

Student Attitudes and Preferences toward an E-Mentoring Program: A Survey of Journalism Students

ERIC Educational Resources Information Center

Switzer, Jamie; Switzer, Ralph

2015-01-01

Advances in information and communication technologies (ICTs) provide new opportunities for mentoring, eliminating the need for a synchronous meeting. We report the findings of a survey that measured university student perceptions of the roles and expectations of online mentors and the likelihood of using an online mentor if given the opportunity.…

Research on Automatic Programming

DTIC Science & Technology

1975-12-31

Sequential processes, deadlocks, and semaphore primitives , Ph.D. Thesis, Harvard University, November 1974; Center for Research in Computing...verified. 13 Code generated to effect the synchronization makes use of the ECL control extension facility (Prenner’s CI, see [Prenner]). The... semaphore operations [Dijkstra] is being developed. Initial results for this code generator are very encouraging; in many cases generated code is

Instructional WebBoard Strategies in Secondary Education and University Teaching.

ERIC Educational Resources Information Center

Siegle, Del; Ward, Layne; McCoach, D. Betsy

The nature of student participation with WebBoard, an electronic bulletin board system that can be used for synchronous and asynchronous discussions among participants, was studied in an action research project in two settings. In one, 67 and 59 high school students of Japanese participated in a course using WebBoard. The number of times students…

Building a Community of Inquiry and Analytical Skills in an Online History Course

ERIC Educational Resources Information Center

Stover, Sheri; Pollock, Sean

2014-01-01

The purpose of this case study was to assess a history instructor's attempt to redesign an introductory history survey course. Traditionally, it has been taught in a face-to-face environment within the university's core curriculum program. It was redesigned as a synchronous online course that provided students with opportunities to work…

Exploring the Role of Distributed Learning in Distance Education at Allama Iqbal Open University: Academic Challenges at Postgraduate Level

ERIC Educational Resources Information Center

Bukhsh, Qadir; Chaudhary, Muhammad Ajmal

2015-01-01

Distributed learning is derived from the concept of distributed resources. Different institutions around the globe connected through network and the learners are diverse, located in the different cultures and communities. Distributed learning provides global standards of quality to all learners through synchronous and asynchronous communications…

Evaluation of Distance Education Components of e-MBA Program--A Case Study

ERIC Educational Resources Information Center

Gunes, Ali; Altintas, Tugba

2013-01-01

By 2008-2009 educational year, distance education e-MBA Program have been added to Graduate School of Social Sciences of Istanbul Aydin University. The distance education components that were used included asynchronous education, synchronous education, exams, the learning management system-web site and a remote live-support desk. At the end of the…

Using Electronic Communication Tools in Online Group Activities to Develop Collaborative Learning Skills

ERIC Educational Resources Information Center

Khalil, Hanan; Ebner, Martin

2017-01-01

The purpose of this study was to investigate the effect of using synchronous and asynchronous communication tools in online group activities to develop collaborative learning skills. An experimental study was implemented on a sample of faculty of education students in Mansoura University. The sample was divided into two groups, a group studied…

Chatting in L2 Spanish: Interactivity, Self-Efficacy and Interpersonal Relations

ERIC Educational Resources Information Center

Sanchez-Castro, Olga; Mrowa-Hopkins, Colette

2012-01-01

This study seeks to examine variations in patterns of interactivity as they are displayed in the ongoing discourse construction of high and low self-efficacy learners of Spanish in the context of computer-mediated-communication. The paper specifically focuses on the analysis of synchronous text chats of six university students of Spanish at…

"Can You Hear Me, Hanoi?" Compensatory Mechanisms Employed in Synchronous Net-Based English Language Learning

ERIC Educational Resources Information Center

Cunningham, Una; Fagersten, Kristy Beers; Holmsten, Elin

2010-01-01

At Dalarna University, Sweden, modes of communication are offered at many points of Kenning's continuum with a web-based learning platform, including asynchronous document exchange and collaborative writing tools, e-mail, recorded lectures in various formats, live streamed lectures with the possibility of text questions to the lecturer in real…

Perceptions of Social Presence among Public University Graduate Students Enrolled in Synchronous and Asynchronous Coursework

ERIC Educational Resources Information Center

Lee, Daniel; Spear, Rita; Kero, Patty

2017-01-01

Students are accessing graduate study online in ever-increasing numbers with interactive experiences differing from those who traditionally enroll in corresponding face-to-face (F2F) classes. Soft skills such as collaboration/teamwork, communication and presentation are important to learning but difficult to practice outside the F2F environment.…

The Virtual Classroom and Catholic School Leadership Preparation: The LMU Certificate in Catholic School Administration (CCSA) Program

ERIC Educational Resources Information Center

Sabatino, Anthony

2016-01-01

Catholic Extension and Loyola Marymount University (LMU) have engaged in a partnership to offer a graduate level, virtual classroom-based Certificate in Catholic School Administration (CCSA) program for novice and prospective leaders in Catholic schools in mission dioceses throughout the United States. This synchronous online Catholic School…

The creation of a synchronous learning environment to support a study abroad program for nursing majors at a traditional liberal arts university.

PubMed

Folse, Victoria N; Jarvis, Carolyn M; Swanlund, Susan L; Timan, Mitzi Runyard

2015-01-01

In response to an increased need for Spanish-speaking and culturally competent nurses, a small private undergraduate-only liberal arts university implemented a semester-long study abroad program for nursing majors in Barcelona, Spain. Prior to the creation of this program, study abroad for nursing students was limited because of prelicensure requirements and limitations of a traditional nursing curriculum. Students studying in Spain enroll in four courses--including two core nursing courses delivered using Polycom hardware and telepresence software by nursing faculty who remain in the United States, a Spanish language course, and one general education course taught either by the University's Spain Director or by an experienced Spanish professor. Participants live with host families and participate in clinical and community observational experiences in Spanish health care agencies. Students then complete direct patient care requirements upon return to the United States. To our knowledge, no other undergraduate-only institution offers a semester-long study abroad experience for nursing majors embedded within the curriculum using synchronous learning; we believe our Spain program, which is in its fourth year being open to nursing majors, is truly an innovative approach to establish cultural competence for undergraduate nursing majors that could serve as a model for other schools of nursing and health disciplines. Copyright © 2015 Elsevier Inc. All rights reserved.

Interpersonal brain synchronization in the right temporo-parietal junction during face-to-face economic exchange.

PubMed

Tang, Honghong; Mai, Xiaoqin; Wang, Shun; Zhu, Chaozhe; Krueger, Frank; Liu, Chao

2016-01-01

In daily life, interpersonal interactions are influenced by uncertainty about other people's intentions. Face-to-face (FF) interaction reduces such uncertainty by providing external visible cues such as facial expression or body gestures and facilitates shared intentionality to promote belief of cooperative decisions and actual cooperative behaviors in interaction. However, so far little is known about interpersonal brain synchronization between two people engaged in naturally occurring FF interactions. In this study, we combined an adapted ultimatum game with functional near-infrared spectroscopy (fNIRS) hyperscanning to investigate how FF interaction impacts interpersonal brain synchronization during economic exchange. Pairs of strangers interacted repeatedly either FF or face-blocked (FB), while their activation was simultaneously measured in the right temporo-parietal junction (rTPJ) and the control region, right dorsolateral prefrontal cortex (rDLPFC). Behaviorally, FF interactions increased shared intentionality between strangers, leading more positive belief of cooperative decisions and more actual gains in the game. FNIRS results indicated increased interpersonal brain synchronizations during FF interactions in rTPJ (but not in rDLPFC) with greater shared intentionality between partners. These results highlighted the importance of rTPJ in collaborative social interactions during FF economic exchange and warrant future research that combines FF interactions with fNIRS hyperscanning to study social brain disorders such as autism. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Network synchronization in hippocampal neurons.

PubMed

Penn, Yaron; Segal, Menahem; Moses, Elisha

2016-03-22

Oscillatory activity is widespread in dynamic neuronal networks. The main paradigm for the origin of periodicity consists of specialized pacemaking elements that synchronize and drive the rest of the network; however, other models exist. Here, we studied the spontaneous emergence of synchronized periodic bursting in a network of cultured dissociated neurons from rat hippocampus and cortex. Surprisingly, about 60% of all active neurons were self-sustained oscillators when disconnected, each with its own natural frequency. The individual neuron's tendency to oscillate and the corresponding oscillation frequency are controlled by its excitability. The single neuron intrinsic oscillations were blocked by riluzole, and are thus dependent on persistent sodium leak currents. Upon a gradual retrieval of connectivity, the synchrony evolves: Loose synchrony appears already at weak connectivity, with the oscillators converging to one common oscillation frequency, yet shifted in phase across the population. Further strengthening of the connectivity causes a reduction in the mean phase shifts until zero-lag is achieved, manifested by synchronous periodic network bursts. Interestingly, the frequency of network bursting matches the average of the intrinsic frequencies. Overall, the network behaves like other universal systems, where order emerges spontaneously by entrainment of independent rhythmic units. Although simplified with respect to circuitry in the brain, our results attribute a basic functional role for intrinsic single neuron excitability mechanisms in driving the network's activity and dynamics, contributing to our understanding of developing neural circuits.

Implementing universal nonadiabatic holonomic quantum gates with transmons

NASA Astrophysics Data System (ADS)

Hong, Zhuo-Ping; Liu, Bao-Jie; Cai, Jia-Qi; Zhang, Xin-Ding; Hu, Yong; Wang, Z. D.; Xue, Zheng-Yuan

2018-02-01

Geometric phases are well known to be noise resilient in quantum evolutions and operations. Holonomic quantum gates provide us with a robust way towards universal quantum computation, as these quantum gates are actually induced by non-Abelian geometric phases. Here we propose and elaborate how to efficiently implement universal nonadiabatic holonomic quantum gates on simpler superconducting circuits, with a single transmon serving as a qubit. In our proposal, an arbitrary single-qubit holonomic gate can be realized in a single-loop scenario by varying the amplitudes and phase difference of two microwave fields resonantly coupled to a transmon, while nontrivial two-qubit holonomic gates may be generated with a transmission-line resonator being simultaneously coupled to the two target transmons in an effective resonant way. Moreover, our scenario may readily be scaled up to a two-dimensional lattice configuration, which is able to support large scalable quantum computation, paving the way for practically implementing universal nonadiabatic holonomic quantum computation with superconducting circuits.

The Psychology of Music: Rhythm and Movement.

PubMed

Levitin, Daniel J; Grahn, Jessica A; London, Justin

2018-01-04

The urge to move to music is universal among humans. Unlike visual art, which is manifest across space, music is manifest across time. When listeners get carried away by the music, either through movement (such as dancing) or through reverie (such as trance), it is usually the temporal qualities of the music-its pulse, tempo, and rhythmic patterns-that put them in this state. In this article, we review studies addressing rhythm, meter, movement, synchronization, entrainment, the perception of groove, and other temporal factors that constitute a first step to understanding how and why music literally moves us. The experiments we review span a range of methodological techniques, including neuroimaging, psychophysics, and traditional behavioral experiments, and we also summarize the current studies of animal synchronization, engaging an evolutionary perspective on human rhythmic perception and cognition.

Unified approach to redshift in cosmological/black hole spacetimes and synchronous frame

NASA Astrophysics Data System (ADS)

Toporensky, A. V.; Zaslavskii, O. B.; Popov, S. B.

2018-01-01

Usually, interpretation of redshift in static spacetimes (for example, near black holes) is opposed to that in cosmology. In this methodological note, we show that both explanations are unified in a natural picture. This is achieved if, considering the static spacetime, one (i) makes a transition to a synchronous frame, and (ii) returns to the original frame by means of local Lorentz boost. To reach our goal, we consider a rather general class of spherically symmetric spacetimes. In doing so, we construct frames that generalize the well-known Lemaitre and Painlevé-Gullstand ones and elucidate the relation between them. This helps us to understand, in a unifying approach, how gravitation reveals itself in different branches of general relativity. This framework can be useful for general relativity university courses.

Digital phonocardiographic experiments and signal processing in multidisciplinary fields of university education

NASA Astrophysics Data System (ADS)

Nagy, Tamás; Vadai, Gergely; Gingl, Zoltán

2017-09-01

Modern measurement of physical signals is based on the use of sensors, electronic signal conditioning, analog-to-digital conversion and digital signal processing carried out by dedicated software. The same signal chain is used in many devices such as home appliances, automotive electronics, medical instruments, and smartphones. Teaching the theoretical, experimental, and signal processing background must be an essential part of improving the standard of higher education, and it fits well to the increasingly multidisciplinary nature of physics and engineering too. In this paper, we show how digital phonocardiography can be used in university education as a universal, highly scalable, exciting, and inspiring laboratory practice and as a demonstration at various levels and complexity. We have developed open-source software templates in modern programming languages to support immediate use and to serve as a basis of further modifications using personal computers, tablets, and smartphones.

Hybrid petacomputing meets cosmology: The Roadrunner Universe project

NASA Astrophysics Data System (ADS)

Habib, Salman; Pope, Adrian; Lukić, Zarija; Daniel, David; Fasel, Patricia; Desai, Nehal; Heitmann, Katrin; Hsu, Chung-Hsing; Ankeny, Lee; Mark, Graham; Bhattacharya, Suman; Ahrens, James

2009-07-01

The target of the Roadrunner Universe project at Los Alamos National Laboratory is a set of very large cosmological N-body simulation runs on the hybrid supercomputer Roadrunner, the world's first petaflop platform. Roadrunner's architecture presents opportunities and difficulties characteristic of next-generation supercomputing. We describe a new code designed to optimize performance and scalability by explicitly matching the underlying algorithms to the machine architecture, and by using the physics of the problem as an essential aid in this process. While applications will differ in specific exploits, we believe that such a design process will become increasingly important in the future. The Roadrunner Universe project code, MC3 (Mesh-based Cosmology Code on the Cell), uses grid and direct particle methods to balance the capabilities of Roadrunner's conventional (Opteron) and accelerator (Cell BE) layers. Mirrored particle caches and spectral techniques are used to overcome communication bandwidth limitations and possible difficulties with complicated particle-grid interaction templates.

Nontraditional Students' Perception of a Blended Course: Integrating Synchronous Online Discussion and Face-to-Face Instruction

ERIC Educational Resources Information Center

Blankson, Joseph; Kyei-Blankson, Lydia

2008-01-01

Nontraditional students are rapidly becoming the majority group on campuses across America. These students are often hard pressed for time and in order to provide them with equal learning opportunities many universities and colleges are currently responding by offering classes using a variety of delivery methods and formats. In this study,…

Absence of Copula and the Notion of Simplicity: A Study of Normal Speech, Baby Talk, Foreigner Talk and Pidgins.

ERIC Educational Resources Information Center

Ferguson, Charles A.

For the linguist interested in typology and language universals, this paper suggests the usefulness of a taxonomy of copula and copula-like constructions in the world's languages and the elaboration of hypotheses of synchronic variation and diachronic change in this part of language. For the linguist interested in child language development, the…

The Enemy Objectives Unit in World War II: Selecting Targets for Aerial Bombardment that Support the Political Purpose of War

DTIC Science & Technology

2011-05-19

Planning Staffs .......................................................................................... 26 Operation Octopus ...University Press, 2003), 96. 28 Operation Octopus Having established credibility, the EOU assigned its analysts to branches of the US air and...synchronize efforts. The EOU members coined this effort Operation Octopus . This operation was critical for the EOU as it allowed EOU members to

The Effect of Task Types on Foreign Language Learners' Social Presence in Synchronous Computer Mediated Communication (SCMC)

ERIC Educational Resources Information Center

Ko, Chao-Jung

2016-01-01

This study aims to clarify the relationship between task types and foreign language learners' social presence (SP) in text-based SCMC learning modes. The participants in this study comprised 38 high-intermediate level English as a foreign language (EFL) learners from different disciplines of a university in Taiwan. They were divided into two…

Diving into Lake Devo: Modes of Representation and Means of Interaction and Reflection in Online Role-Play

ERIC Educational Resources Information Center

Koechli, Linda; Glynn, Maureen

2014-01-01

This paper outlines an action research project involving the development of an educational online role-playing website, known as Lake Devo. Designed in keeping with constructivist principles, the website is used in select post-secondary courses at Ryerson University and allows learners to work synchronously, using visual, audio, and text elements…

A Hospital Local Area Communication Network—The First Year's Experience

PubMed Central

Simborg, D. W.; Chadwick, M.; Whiting-O'Keefe, Q. E.; Tolchin, S. G.; Stewart, R. L.; Kahn, S. A.; Bergan, E. S.; Gafke, G. P.

1982-01-01

A local area communications network has been implemented at the University of California, San Francisco Hospital to integrate major components of the hospital's information system. This microprocessor-based network technology was developed by The Applied Physics Laboratory of the Johns Hopkins University. The first year's experience has demonstrated the basic feasibility of this technology in simplifying the integration of diverse hardware and software systems. Four minicomputer-based UCSF systems now use the network to synchronize key patient identification and registration information among the systems. Clinical uses of the network will begin during the second year of the project.

Childhood pneumonia diagnostics: community health workers' and national stakeholders' differing perspectives of new and existing aids.

PubMed

Spence, Hollie; Baker, Kevin; Wharton-Smith, Alexandra; Mucunguzi, Akasiima; Matata, Lena; Habte, Tedila; Nanyumba, Diana; Sebsibe, Anteneh; Thany, Thol; Källander, Karin

2017-01-01

Pneumonia heavily contributes to global under-five mortality. Many countries use community case management to detect and treat childhood pneumonia. Community health workers (CHWs) have limited tools to help them assess signs of pneumonia. New respiratory rate (RR) counting devices and pulse oximeters are being considered for this purpose. To explore perspectives of CHWs and national stakeholders regarding the potential usability and scalability of seven devices to aid community assessment of pneumonia signs. Pile sorting was conducted to rate the usability and scalability of 7 different RR counting aids and pulse oximeters amongst 16 groups of participants. Following each pile-sorting session, a focus group discussion (FGD) explored participants' sorting rationale. Purposive sampling was used to select CHWs and national stakeholders with experience in childhood pneumonia and integrated community case management (iCCM) in Cambodia, Ethiopia, Uganda and South Sudan. Pile-sorting data were aggregated for countries and participant groups. FGDs were audio recorded and transcribed verbatim. Translated FGDs transcripts were coded in NVivo 10 and analysed using thematic content analysis. Comparative analysis was performed between countries and groups to identify thematic patterns. CHWs and national stakeholders across the four countries perceived the acute respiratory infection (ARI) timer and fingertip pulse oximeter as highly scalable and easy for CHWs to use. National stakeholders were less receptive to new technologies. CHWs placed greater priority on device acceptability to caregivers and children. Both groups felt that heavy reliance on electricity reduced potential scalability and usability in rural areas. Device simplicity, affordability and sustainability were universally valued. CHWs and national stakeholders prioritise different device characteristics according to their specific focus of work. The views of all relevant stakeholders, including health workers, policy makers, children and parents, should be considered in future policy decisions, research and development regarding suitable pneumonia diagnostic aids for community use.

Geocomputation over Hybrid Computer Architecture and Systems: Prior Works and On-going Initiatives at UARK

NASA Astrophysics Data System (ADS)

Shi, X.

2015-12-01

As NSF indicated - "Theory and experimentation have for centuries been regarded as two fundamental pillars of science. It is now widely recognized that computational and data-enabled science forms a critical third pillar." Geocomputation is the third pillar of GIScience and geosciences. With the exponential growth of geodata, the challenge of scalable and high performance computing for big data analytics become urgent because many research activities are constrained by the inability of software or tool that even could not complete the computation process. Heterogeneous geodata integration and analytics obviously magnify the complexity and operational time frame. Many large-scale geospatial problems may be not processable at all if the computer system does not have sufficient memory or computational power. Emerging computer architectures, such as Intel's Many Integrated Core (MIC) Architecture and Graphics Processing Unit (GPU), and advanced computing technologies provide promising solutions to employ massive parallelism and hardware resources to achieve scalability and high performance for data intensive computing over large spatiotemporal and social media data. Exploring novel algorithms and deploying the solutions in massively parallel computing environment to achieve the capability for scalable data processing and analytics over large-scale, complex, and heterogeneous geodata with consistent quality and high-performance has been the central theme of our research team in the Department of Geosciences at the University of Arkansas (UARK). New multi-core architectures combined with application accelerators hold the promise to achieve scalability and high performance by exploiting task and data levels of parallelism that are not supported by the conventional computing systems. Such a parallel or distributed computing environment is particularly suitable for large-scale geocomputation over big data as proved by our prior works, while the potential of such advanced infrastructure remains unexplored in this domain. Within this presentation, our prior and on-going initiatives will be summarized to exemplify how we exploit multicore CPUs, GPUs, and MICs, and clusters of CPUs, GPUs and MICs, to accelerate geocomputation in different applications.

Rapid high-yield expression of full-size IgG antibodies in plants coinfected with noncompeting viral vectors

PubMed Central

Giritch, Anatoli; Marillonnet, Sylvestre; Engler, Carola; van Eldik, Gerben; Botterman, Johan; Klimyuk, Victor; Gleba, Yuri

2006-01-01

Plant viral vectors allow expression of heterologous proteins at high yields, but so far, they have been unable to express heterooligomeric proteins efficiently. We describe here a rapid and indefinitely scalable process for high-level expression of functional full-size mAbs of the IgG class in plants. The process relies on synchronous coinfection and coreplication of two viral vectors, each expressing a separate antibody chain. The two vectors are derived from two different plant viruses that were found to be noncompeting. Unlike vectors derived from the same virus, noncompeting vectors effectively coexpress the heavy and light chains in the same cell throughout the plant body, resulting in yields of up to 0.5 g of assembled mAbs per kg of fresh-leaf biomass. This technology allows production of gram quantities of mAbs for research purposes in just several days, and the same protocol can be used on an industrial scale in situations requiring rapid response, such as pandemic or terrorism events. PMID:16973752

Enabling a high throughput real time data pipeline for a large radio telescope array with GPUs

NASA Astrophysics Data System (ADS)

Edgar, R. G.; Clark, M. A.; Dale, K.; Mitchell, D. A.; Ord, S. M.; Wayth, R. B.; Pfister, H.; Greenhill, L. J.

2010-10-01

The Murchison Widefield Array (MWA) is a next-generation radio telescope currently under construction in the remote Western Australia Outback. Raw data will be generated continuously at 5 GiB s-1, grouped into 8 s cadences. This high throughput motivates the development of on-site, real time processing and reduction in preference to archiving, transport and off-line processing. Each batch of 8 s data must be completely reduced before the next batch arrives. Maintaining real time operation will require a sustained performance of around 2.5 TFLOP s-1 (including convolutions, FFTs, interpolations and matrix multiplications). We describe a scalable heterogeneous computing pipeline implementation, exploiting both the high computing density and FLOP-per-Watt ratio of modern GPUs. The architecture is highly parallel within and across nodes, with all major processing elements performed by GPUs. Necessary scatter-gather operations along the pipeline are loosely synchronized between the nodes hosting the GPUs. The MWA will be a frontier scientific instrument and a pathfinder for planned peta- and exa-scale facilities.

Service Management Database for DSN Equipment

NASA Technical Reports Server (NTRS)

Zendejas, Silvino; Bui, Tung; Bui, Bach; Malhotra, Shantanu; Chen, Fannie; Wolgast, Paul; Allen, Christopher; Luong, Ivy; Chang, George; Sadaqathulla, Syed

2009-01-01

This data- and event-driven persistent storage system leverages the use of commercial software provided by Oracle for portability, ease of maintenance, scalability, and ease of integration with embedded, client-server, and multi-tiered applications. In this role, the Service Management Database (SMDB) is a key component of the overall end-to-end process involved in the scheduling, preparation, and configuration of the Deep Space Network (DSN) equipment needed to perform the various telecommunication services the DSN provides to its customers worldwide. SMDB makes efficient use of triggers, stored procedures, queuing functions, e-mail capabilities, data management, and Java integration features provided by the Oracle relational database management system. SMDB uses a third normal form schema design that allows for simple data maintenance procedures and thin layers of integration with client applications. The software provides an integrated event logging system with ability to publish events to a JMS messaging system for synchronous and asynchronous delivery to subscribed applications. It provides a structured classification of events and application-level messages stored in database tables that are accessible by monitoring applications for real-time monitoring or for troubleshooting and analysis over historical archives.

Multi-mode sensor processing on a dynamically reconfigurable massively parallel processor array

NASA Astrophysics Data System (ADS)

Chen, Paul; Butts, Mike; Budlong, Brad; Wasson, Paul

2008-04-01

This paper introduces a novel computing architecture that can be reconfigured in real time to adapt on demand to multi-mode sensor platforms' dynamic computational and functional requirements. This 1 teraOPS reconfigurable Massively Parallel Processor Array (MPPA) has 336 32-bit processors. The programmable 32-bit communication fabric provides streamlined inter-processor connections with deterministically high performance. Software programmability, scalability, ease of use, and fast reconfiguration time (ranging from microseconds to milliseconds) are the most significant advantages over FPGAs and DSPs. This paper introduces the MPPA architecture, its programming model, and methods of reconfigurability. An MPPA platform for reconfigurable computing is based on a structural object programming model. Objects are software programs running concurrently on hundreds of 32-bit RISC processors and memories. They exchange data and control through a network of self-synchronizing channels. A common application design pattern on this platform, called a work farm, is a parallel set of worker objects, with one input and one output stream. Statically configured work farms with homogeneous and heterogeneous sets of workers have been used in video compression and decompression, network processing, and graphics applications.

On Parallelizing Single Dynamic Simulation Using HPC Techniques and APIs of Commercial Software

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

Diao, Ruisheng; Jin, Shuangshuang; Howell, Frederic

Time-domain simulations are heavily used in today’s planning and operation practices to assess power system transient stability and post-transient voltage/frequency profiles following severe contingencies to comply with industry standards. Because of the increased modeling complexity, it is several times slower than real time for state-of-the-art commercial packages to complete a dynamic simulation for a large-scale model. With the growing stochastic behavior introduced by emerging technologies, power industry has seen a growing need for performing security assessment in real time. This paper presents a parallel implementation framework to speed up a single dynamic simulation by leveraging the existing stability model librarymore » in commercial tools through their application programming interfaces (APIs). Several high performance computing (HPC) techniques are explored such as parallelizing the calculation of generator current injection, identifying fast linear solvers for network solution, and parallelizing data outputs when interacting with APIs in the commercial package, TSAT. The proposed method has been tested on a WECC planning base case with detailed synchronous generator models and exhibits outstanding scalable performance with sufficient accuracy.« less

Programming Cells for Dynamic Assembly of Inorganic Nano-Objects with Spatiotemporal Control.

PubMed

Wang, Xinyu; Pu, Jiahua; An, Bolin; Li, Yingfeng; Shang, Yuequn; Ning, Zhijun; Liu, Yi; Ba, Fang; Zhang, Jiaming; Zhong, Chao

2018-04-01

Programming living cells to organize inorganic nano-objects (NOs) in a spatiotemporally precise fashion would advance new techniques for creating ordered ensembles of NOs and new bio-abiotic hybrid materials with emerging functionalities. Bacterial cells often grow in cellular communities called biofilms. Here, a strategy is reported for programming dynamic biofilm formation for the synchronized assembly of discrete NOs or hetero-nanostructures on diverse interfaces in a dynamic, scalable, and hierarchical fashion. By engineering Escherichia coli to sense blue light and respond by producing biofilm curli fibers, biofilm formation is spatially controlled and the patterned NOs' assembly is simultaneously achieved. Diverse and complex fluorescent quantum dot patterns with a minimum patterning resolution of 100 µm are demonstrated. By temporally controlling the sequential addition of NOs into the culture, multilayered heterostructured thin films are fabricated through autonomous layer-by-layer assembly. It is demonstrated that biologically dynamic self-assembly can be used to advance a new repertoire of nanotechnologies and materials with increasing complexity that would be otherwise challenging to produce. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

ROCK inhibitor is not required for embryoid body formation from singularized human embryonic stem cells.

PubMed

Pettinato, Giuseppe; Vanden Berg-Foels, Wendy S; Zhang, Ning; Wen, Xuejun

2014-01-01

We report a technology to form human embryoid bodies (hEBs) from singularized human embryonic stem cells (hESCs) without the use of the p160 rho-associated coiled-coil kinase inhibitor (ROCKi) or centrifugation (spin). hEB formation was tested under four conditions: +ROCKi/+spin, +ROCKi/-spin, -ROCKi/+spin, and -ROCKi/-spin. Cell suspensions of BG01V/hOG and H9 hESC lines were pipetted into non-adherent hydrogel substrates containing defined microwell arrays. hEBs of consistent size and spherical geometry can be formed in each of the four conditions, including the -ROCKi/-spin condition. The hEBs formed under the -ROCKi/-spin condition differentiated to develop the three embryonic germ layers and tissues derived from each of the germ layers. This simplified hEB production technique offers homogeneity in hEB size and shape to support synchronous differentiation, elimination of the ROCKi xeno-factor and rate-limiting centrifugation treatment, and low-cost scalability, which will directly support automated, large-scale production of hEBs and hESC-derived cells needed for clinical, research, or therapeutic applications.

Performances of multiprocessor multidisk architectures for continuous media storage

NASA Astrophysics Data System (ADS)

Gennart, Benoit A.; Messerli, Vincent; Hersch, Roger D.

1996-03-01

Multimedia interfaces increase the need for large image databases, capable of storing and reading streams of data with strict synchronicity and isochronicity requirements. In order to fulfill these requirements, we consider a parallel image server architecture which relies on arrays of intelligent disk nodes, each disk node being composed of one processor and one or more disks. This contribution analyzes through bottleneck performance evaluation and simulation the behavior of two multi-processor multi-disk architectures: a point-to-point architecture and a shared-bus architecture similar to current multiprocessor workstation architectures. We compare the two architectures on the basis of two multimedia algorithms: the compute-bound frame resizing by resampling and the data-bound disk-to-client stream transfer. The results suggest that the shared bus is a potential bottleneck despite its very high hardware throughput (400Mbytes/s) and that an architecture with addressable local memories located closely to their respective processors could partially remove this bottleneck. The point- to-point architecture is scalable and able to sustain high throughputs for simultaneous compute- bound and data-bound operations.

Optimal network modification for spectral radius dependent phase transitions

NASA Astrophysics Data System (ADS)

Rosen, Yonatan; Kirsch, Lior; Louzoun, Yoram

2016-09-01

The dynamics of contact processes on networks is often determined by the spectral radius of the networks adjacency matrices. A decrease of the spectral radius can prevent the outbreak of an epidemic, or impact the synchronization among systems of coupled oscillators. The spectral radius is thus tightly linked to network dynamics and function. As such, finding the minimal change in network structure necessary to reach the intended spectral radius is important theoretically and practically. Given contemporary big data resources such as large scale communication or social networks, this problem should be solved with a low runtime complexity. We introduce a novel method for the minimal decrease in weights of edges required to reach a given spectral radius. The problem is formulated as a convex optimization problem, where a global optimum is guaranteed. The method can be easily adjusted to an efficient discrete removal of edges. We introduce a variant of the method which finds optimal decrease with a focus on weights of vertices. The proposed algorithm is exceptionally scalable, solving the problem for real networks of tens of millions of edges in a short time.

Motion-adaptive model-assisted compatible coding with spatiotemporal scalability

NASA Astrophysics Data System (ADS)

Lee, JaeBeom; Eleftheriadis, Alexandros

1997-01-01

We introduce the concept of motion adaptive spatio-temporal model-assisted compatible (MA-STMAC) coding, a technique to selectively encode areas of different importance to the human eye in terms of space and time in moving images with the consideration of object motion. PRevious STMAC was proposed base don the fact that human 'eye contact' and 'lip synchronization' are very important in person-to-person communication. Several areas including the eyes and lips need different types of quality, since different areas have different perceptual significance to human observers. The approach provides a better rate-distortion tradeoff than conventional image coding techniques base don MPEG-1, MPEG- 2, H.261, as well as H.263. STMAC coding is applied on top of an encoder, taking full advantage of its core design. Model motion tracking in our previous STMAC approach was not automatic. The proposed MA-STMAC coding considers the motion of the human face within the STMAC concept using automatic area detection. Experimental results are given using ITU-T H.263, addressing very low bit-rate compression.

Multichannel Networked Phasemeter Readout and Analysis

NASA Technical Reports Server (NTRS)

Edmonds, Karina

2008-01-01

Netmeter software reads a data stream from up to 250 networked phasemeters, synchronizes the data, saves the reduced data to disk (after applying a low-pass filter), and provides a Web server interface for remote control. Unlike older phasemeter software that requires a special, real-time operating system, this program can run on any general-purpose computer. It needs about five percent of the CPU (central processing unit) to process 20 channels because it adds built-in data logging and network-based GUIs (graphical user interfaces) that are implemented in Scalable Vector Graphics (SVG). Netmeter runs on Linux and Windows. It displays the instantaneous displacements measured by several phasemeters at a user-selectable rate, up to 1 kHz. The program monitors the measure and reference channel frequencies. For ease of use, levels of status in Netmeter are color coded: green for normal operation, yellow for network errors, and red for optical misalignment problems. Netmeter includes user-selectable filters up to 4 k samples, and user-selectable averaging windows (after filtering). Before filtering, the program saves raw data to disk using a burst-write technique.

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.

Questions on universal constants and four-dimensional symmetry from a broad viewpoint. I

NASA Technical Reports Server (NTRS)

Hsu, J. P.

1983-01-01

It is demonstrated that there is a flexibility in clock synchronizations and that four-dimensional symmetry framework can be viewed broadly. The true universality of basic constants is discussed, considering a class of measurement processes based on the velocity = distance/time interval, which always yields some number when used by an observer. The four-dimensional symmetry framework based on common time for all observers is formulated, and related processes of measuring light speed are discussed. Invariant 'action functions' for physical laws in the new four-dimensional symmetry framework with the common time are established to discuss universal constants. Truly universal constants are demonstrated, and it is shown that physics in this new framework and in special relativity are equivalent as far as one-particle systems and the S-matrix in field theories are concerned.

A system to build distributed multivariate models and manage disparate data sharing policies: implementation in the scalable national network for effectiveness research.

PubMed

Meeker, Daniella; Jiang, Xiaoqian; Matheny, Michael E; Farcas, Claudiu; D'Arcy, Michel; Pearlman, Laura; Nookala, Lavanya; Day, Michele E; Kim, Katherine K; Kim, Hyeoneui; Boxwala, Aziz; El-Kareh, Robert; Kuo, Grace M; Resnic, Frederic S; Kesselman, Carl; Ohno-Machado, Lucila

2015-11-01

Centralized and federated models for sharing data in research networks currently exist. To build multivariate data analysis for centralized networks, transfer of patient-level data to a central computation resource is necessary. The authors implemented distributed multivariate models for federated networks in which patient-level data is kept at each site and data exchange policies are managed in a study-centric manner. The objective was to implement infrastructure that supports the functionality of some existing research networks (e.g., cohort discovery, workflow management, and estimation of multivariate analytic models on centralized data) while adding additional important new features, such as algorithms for distributed iterative multivariate models, a graphical interface for multivariate model specification, synchronous and asynchronous response to network queries, investigator-initiated studies, and study-based control of staff, protocols, and data sharing policies. Based on the requirements gathered from statisticians, administrators, and investigators from multiple institutions, the authors developed infrastructure and tools to support multisite comparative effectiveness studies using web services for multivariate statistical estimation in the SCANNER federated network. The authors implemented massively parallel (map-reduce) computation methods and a new policy management system to enable each study initiated by network participants to define the ways in which data may be processed, managed, queried, and shared. The authors illustrated the use of these systems among institutions with highly different policies and operating under different state laws. Federated research networks need not limit distributed query functionality to count queries, cohort discovery, or independently estimated analytic models. Multivariate analyses can be efficiently and securely conducted without patient-level data transport, allowing institutions with strict local data storage requirements to participate in sophisticated analyses based on federated research networks. © The Author 2015. Published by Oxford University Press on behalf of the American Medical Informatics Association.

University of Arizona Compressed Air Energy Storage

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

Simmons, Joseph; Muralidharan, Krishna

2012-12-31

Boiled down to its essentials, the grant’s purpose was to develop and demonstrate the viability of compressed air energy storage (CAES) for use in renewable energy development. While everyone agrees that energy storage is the key component to enable widespread adoption of renewable energy sources, the development of a viable scalable technology has been missing. The Department of Energy has focused on expanded battery research and improved forecasting, and the utilities have deployed renewable energy resources only to the extent of satisfying Renewable Portfolio Standards. The lack of dispatchability of solar and wind-based electricity generation has drastically increased the costmore » of operation with these components. It is now clear that energy storage coupled with accurate solar and wind forecasting make up the only combination that can succeed in dispatchable renewable energy resources. Conventional batteries scale linearly in size, so the price becomes a barrier for large systems. Flow batteries scale sub-linearly and promise to be useful if their performance can be shown to provide sufficient support for solar and wind-base electricity generation resources. Compressed air energy storage provides the most desirable answer in terms of scalability and performance in all areas except efficiency. With the support of the DOE, Tucson Electric Power and Science Foundation Arizona, the Arizona Research Institute for Solar Energy (AzRISE) at the University of Arizona has had the opportunity to investigate CAES as a potential energy storage resource.« less

A precise clock distribution network for MRPC-based experiments

NASA Astrophysics Data System (ADS)

Wang, S.; Cao, P.; Shang, L.; An, Q.

2016-06-01

In high energy physics experiments, the MRPC (Multi-Gap Resistive Plate Chamber) detectors are widely used recently which can provide higher-resolution measurement for particle identification. However, the application of MRPC detectors leads to a series of challenges in electronics design with large number of front-end electronic channels, especially for distributing clock precisely. To deal with these challenges, this paper presents a universal scheme of clock transmission network for MRPC-based experiments with advantages of both precise clock distribution and global command synchronization. For precise clock distributing, the clock network is designed into a tree architecture with two stages: the first one has a point-to-multipoint long range bidirectional distribution with optical channels and the second one has a fan-out structure with copper link inside readout crates. To guarantee the precision of clock frequency or phase, the r-PTP (reduced Precision Time Protocol) and the DDMTD (digital Dual Mixer Time Difference) methods are used for frequency synthesis, phase measurement and adjustment, which is implemented by FPGA (Field Programmable Gate Array) in real-time. In addition, to synchronize global command execution, based upon this clock distribution network, synchronous signals are coded with clock for transmission. With technique of encoding/decoding and clock data recovery, signals such as global triggers or system control commands, can be distributed to all front-end channels synchronously, which greatly simplifies the system design. The experimental results show that both the clock jitter (RMS) and the clock skew can be less than 100 ps.

Second-order cosmological perturbations. I. Produced by scalar-scalar coupling in synchronous gauge

NASA Astrophysics Data System (ADS)

Wang, Bo; Zhang, Yang

2017-11-01

We present a systematic study of the 2nd-order scalar, vector, and tensor metric perturbations in the Einstein-de Sitter Universe in synchronous coordinates. For the scalar-scalar coupling between 1st-order perturbations, we decompose the 2nd-order perturbed Einstein equation into the respective field equations of 2nd-order scalar, vector, and tensor perturbations, and obtain their solutions with general initial conditions. In particular, the decaying modes of solution are included, the 2nd-order vector is generated even if the 1st-order vector is absent, and the solution of the 2nd-order tensor corrects that in literature. We perform general synchronous-to-synchronous gauge transformations up to 2nd order generated by a 1st-order vector field ξ(1 )μ and a 2nd-order ξ(2 )μ . All the residual gauge modes of 2nd-order metric perturbations and density contrast are found, and their number is substantially reduced when the transformed 3-velocity of dust is set to zero. Moreover, we show that only ξ(2 )μ is effective in carrying out 2nd-order transformations that we consider, because ξ(1 )μ has been used in obtaining the 1st-order perturbations. Holding the 1st-order perturbations fixed, the transformations by ξ(2 )μ on the 2nd-order perturbations have the same structure as those by ξ(1 )μ on the 1st-order perturbations.

The 20-minute team--a critical case study from the emergency room.

PubMed

Berlin, Johan M; Carlström, Eric D

2008-08-01

In this article, the difference between team and group is tested empirically. The research question posed is How are teams formed? Three theoretical concepts that distinguish groups from teams are presented: sequentiality, parallelism and synchronicity. The presumption is that groups cooperate sequentially and teams synchronously, while parallel cooperation is a transition between group and team. To answer the question, a longitudinal case study has been made of a trauma team at a university hospital. Data have been collected through interviews and direct observations. Altogether the work of the trauma team has been studied for a period of 5 years (2002-2006). The results indicate that two factors are of central importance for the creation of a team. The first is related to its management and the other to the forms of cooperation. To allow for a team to act rapidly and to reduce friction between different members, clear leadership is required. The studied team developed cooperation with synchronous elements but never attained a level that corresponds to idealized conceptions of teams. This is used as a basis for challenging ideas that teams are harmonious and free from conflicts and that cooperation takes place without friction.

Real-time time-division color electroholography using a single GPU and a USB module for synchronizing reference light.

PubMed

Araki, Hiromitsu; Takada, Naoki; Niwase, Hiroaki; Ikawa, Shohei; Fujiwara, Masato; Nakayama, Hirotaka; Kakue, Takashi; Shimobaba, Tomoyoshi; Ito, Tomoyoshi

2015-12-01

We propose real-time time-division color electroholography using a single graphics processing unit (GPU) and a simple synchronization system of reference light. To facilitate real-time time-division color electroholography, we developed a light emitting diode (LED) controller with a universal serial bus (USB) module and the drive circuit for reference light. A one-chip RGB LED connected to a personal computer via an LED controller was used as the reference light. A single GPU calculates three computer-generated holograms (CGHs) suitable for red, green, and blue colors in each frame of a three-dimensional (3D) movie. After CGH calculation using a single GPU, the CPU can synchronize the CGH display with the color switching of the one-chip RGB LED via the LED controller. Consequently, we succeeded in real-time time-division color electroholography for a 3D object consisting of around 1000 points per color when an NVIDIA GeForce GTX TITAN was used as the GPU. Furthermore, we implemented the proposed method in various GPUs. The experimental results showed that the proposed method was effective for various GPUs.

Analysis of Generator Oscillation Characteristics Based on Multiple Synchronized Phasor Measurements

NASA Astrophysics Data System (ADS)

Hashiguchi, Takuhei; Yoshimoto, Masamichi; Mitani, Yasunori; Saeki, Osamu; Tsuji, Kiichiro

In recent years, there has been considerable interest in the on-line measurement, such as observation of power system dynamics and evaluation of machine parameters. On-line methods are particularly attractive since the machine’s service need not be interrupted and parameter estimation is performed by processing measurements obtained during the normal operation of the machine. Authors placed PMU (Phasor Measurement Unit) connected to 100V outlets in some Universities in the 60Hz power system and examine oscillation characteristics in power system. PMU is synchronized based on the global positioning system (GPS) and measured data are transmitted via Internet. This paper describes an application of PMU for generator oscillation analysis. The purpose of this paper is to show methods for processing phase difference and to estimate damping coeffcient and natural angular frequency from phase difference at steady state.

ICASE Semiannual Report, 1 April 1990 - 30 September 1990

DTIC Science & Technology

1990-11-01

underlies parallel simulation protocols that synchronize based on logical time (all known approaches). This framework describes a suf- ficient set of...conducted primarily by visiting scientists from universities and from industry, who have resident appointments for limited periods of time , and by consultants...wave equation with point sources and semireflecting impedance boundary conditions. For sources that are piece- wise polynomial in time we get a finite

The Role of Discussion Boards in a University Blended Learning Program (El papel de los foros de discusión en un programa universitario de aprendizaje mixto)

ERIC Educational Resources Information Center

González Moreno, Rosa Isabel

2011-01-01

Discussion boards as tools in blended "English language" learning programs have unique characteristics when compared to other synchronous and asynchronous communication tools that are different. Therefore, it is important to investigate the way they operate, their role within a given program and the students', teachers' and tutors'…

Employing the EPEC Hierarchy of Conditions (Version II) to Evaluate the Effectiveness of Using Synchronous Technologies with Multi-Location Student Cohorts in the Tertiary Education Setting

ERIC Educational Resources Information Center

Eady, Michelle J.; Woodcock, Stuart; Sisco, Ashley

2017-01-01

As e-learning maintains its popularity worldwide, and university enrolments continue to rise, online tertiary level coursework is increasingly being designed for groups of distributed learners, as opposed to individual students. Many institutions struggle with incorporating all facets of online learning and teaching capabilities with the range and…

Measuring Second Language Proficiency with EEG Synchronization: How Functional Cortical Networks and Hemispheric Involvement Differ as a Function of Proficiency Level in Second Language Speakers

ERIC Educational Resources Information Center

Reiterer, Susanne; Pereda, Ernesto; Bhattacharya, Joydeep

2009-01-01

This article examines the question of whether university-based high-level foreign language and linguistic training can influence brain activation and whether different L2 proficiency groups have different brain activation in terms of lateralization and hemispheric involvement. The traditional and prevailing theory of hemispheric involvement in…

Development of a device to simulate tooth mobility.

PubMed

Erdelt, Kurt-Jürgen; Lamper, Timea

2010-10-01

The testing of new materials under simulation of oral conditions is essential in medicine. For simulation of fracture strength different simulation devices are used for test set-up. The results of these in vitro tests differ because there is no standardization of tooth mobility in simulation devices. The aim of this study is to develop a simulation device that depicts the tooth mobility curve as accurately as possible and creates reproducible and scalable mobility curves. With the aid of published literature and with the help of dentists, average forms of tooth classes were generated. Based on these tooth data, different abutment tooth shapes and different simulation devices were designed with a CAD system and were generated with a Rapid Prototyping system. Then, for all simulation devices the displacement curves were created with a universal testing machine and compared with the tooth mobility curve. With this new information, an improved adapted simulation device was constructed. A simulations device that is able to simulate the mobility curve of natural teeth with high accuracy and where mobility is reproducible and scalable was developed.

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

Barbara Chapman

OpenMP was not well recognized at the beginning of the project, around year 2003, because of its limited use in DoE production applications and the inmature hardware support for an efficient implementation. Yet in the recent years, it has been graduately adopted both in HPC applications, mostly in the form of MPI+OpenMP hybrid code, and in mid-scale desktop applications for scientific and experimental studies. We have observed this trend and worked deligiently to improve our OpenMP compiler and runtimes, as well as to work with the OpenMP standard organization to make sure OpenMP are evolved in the direction close tomore » DoE missions. In the Center for Programming Models for Scalable Parallel Computing project, the HPCTools team at the University of Houston (UH), directed by Dr. Barbara Chapman, has been working with project partners, external collaborators and hardware vendors to increase the scalability and applicability of OpenMP for multi-core (and future manycore) platforms and for distributed memory systems by exploring different programming models, language extensions, compiler optimizations, as well as runtime library support.« less

miTRATA: a web-based tool for microRNA Truncation and Tailing Analysis.

PubMed

Patel, Parth; Ramachandruni, S Deepthi; Kakrana, Atul; Nakano, Mayumi; Meyers, Blake C

2016-02-01

We describe miTRATA, the first web-based tool for microRNA Truncation and Tailing Analysis--the analysis of 3' modifications of microRNAs including the loss or gain of nucleotides relative to the canonical sequence. miTRATA is implemented in Python (version 3) and employs parallel processing modules to enhance its scalability when analyzing multiple small RNA (sRNA) sequencing datasets. It utilizes miRBase, currently version 21, as a source of known microRNAs for analysis. miTRATA notifies user(s) via email to download as well as visualize the results online. miTRATA's strengths lie in (i) its biologist-focused web interface, (ii) improved scalability via parallel processing and (iii) its uniqueness as a webtool to perform microRNA truncation and tailing analysis. miTRATA is developed in Python and PHP. It is available as a web-based application from https://wasabi.dbi.udel.edu/∼apps/ta/. meyers@dbi.udel.edu Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Population-based structural variation discovery with Hydra-Multi.

PubMed

Lindberg, Michael R; Hall, Ira M; Quinlan, Aaron R

2015-04-15

Current strategies for SNP and INDEL discovery incorporate sequence alignments from multiple individuals to maximize sensitivity and specificity. It is widely accepted that this approach also improves structural variant (SV) detection. However, multisample SV analysis has been stymied by the fundamental difficulties of SV calling, e.g. library insert size variability, SV alignment signal integration and detecting long-range genomic rearrangements involving disjoint loci. Extant tools suffer from poor scalability, which limits the number of genomes that can be co-analyzed and complicates analysis workflows. We have developed an approach that enables multisample SV analysis in hundreds to thousands of human genomes using commodity hardware. Here, we describe Hydra-Multi and measure its accuracy, speed and scalability using publicly available datasets provided by The 1000 Genomes Project and by The Cancer Genome Atlas (TCGA). Hydra-Multi is written in C++ and is freely available at https://github.com/arq5x/Hydra. aaronquinlan@gmail.com or ihall@genome.wustl.edu Supplementary data are available at Bioinformatics online. © The Author 2014. Published by Oxford University Press.

Scalability Issues for Remote Sensing Infrastructure: A Case Study.

PubMed

Liu, Yang; Picard, Sean; Williamson, Carey

2017-04-29

For the past decade, a team of University of Calgary researchers has operated a large "sensor Web" to collect, analyze, and share scientific data from remote measurement instruments across northern Canada. This sensor Web receives real-time data streams from over a thousand Internet-connected sensors, with a particular emphasis on environmental data (e.g., space weather, auroral phenomena, atmospheric imaging). Through research collaborations, we had the opportunity to evaluate the performance and scalability of their remote sensing infrastructure. This article reports the lessons learned from our study, which considered both data collection and data dissemination aspects of their system. On the data collection front, we used benchmarking techniques to identify and fix a performance bottleneck in the system's memory management for TCP data streams, while also improving system efficiency on multi-core architectures. On the data dissemination front, we used passive and active network traffic measurements to identify and reduce excessive network traffic from the Web robots and JavaScript techniques used for data sharing. While our results are from one specific sensor Web system, the lessons learned may apply to other scientific Web sites with remote sensing infrastructure.

Optimized autonomous space in-situ sensor web for volcano monitoring

USGS Publications Warehouse

Song, W.-Z.; Shirazi, B.; Huang, R.; Xu, M.; Peterson, N.; LaHusen, R.; Pallister, J.; Dzurisin, D.; Moran, S.; Lisowski, M.; Kedar, S.; Chien, S.; Webb, F.; Kiely, A.; Doubleday, J.; Davies, A.; Pieri, D.

2010-01-01

In response to NASA's announced requirement for Earth hazard monitoring sensor-web technology, a multidisciplinary team involving sensor-network experts (Washington State University), space scientists (JPL), and Earth scientists (USGS Cascade Volcano Observatory (CVO)), have developed a prototype of dynamic and scalable hazard monitoring sensor-web and applied it to volcano monitoring. The combined Optimized Autonomous Space In-situ Sensor-web (OASIS) has two-way communication capability between ground and space assets, uses both space and ground data for optimal allocation of limited bandwidth resources on the ground, and uses smart management of competing demands for limited space assets. It also enables scalability and seamless infusion of future space and in-situ assets into the sensor-web. The space and in-situ control components of the system are integrated such that each element is capable of autonomously tasking the other. The ground in-situ was deployed into the craters and around the flanks of Mount St. Helens in July 2009, and linked to the command and control of the Earth Observing One (EO-1) satellite. ?? 2010 IEEE.

Perovskite Technology is Scalable, But Questions Remain about the Best

Science.gov Websites

Methods | News | NREL Perovskite Technology is Scalable, But Questions Remain about the Best Methods News Release: Perovskite Technology is Scalable, But Questions Remain about the Best Methods NREL be used on a larger surface. The NREL researchers examined potential scalable deposition methods

Vanderbilt University Institute of Imaging Science Center for Computational Imaging XNAT: A multimodal data archive and processing environment.

PubMed

Harrigan, Robert L; Yvernault, Benjamin C; Boyd, Brian D; Damon, Stephen M; Gibney, Kyla David; Conrad, Benjamin N; Phillips, Nicholas S; Rogers, Baxter P; Gao, Yurui; Landman, Bennett A

2016-01-01

The Vanderbilt University Institute for Imaging Science (VUIIS) Center for Computational Imaging (CCI) has developed a database built on XNAT housing over a quarter of a million scans. The database provides framework for (1) rapid prototyping, (2) large scale batch processing of images and (3) scalable project management. The system uses the web-based interfaces of XNAT and REDCap to allow for graphical interaction. A python middleware layer, the Distributed Automation for XNAT (DAX) package, distributes computation across the Vanderbilt Advanced Computing Center for Research and Education high performance computing center. All software are made available in open source for use in combining portable batch scripting (PBS) grids and XNAT servers. Copyright © 2015 Elsevier Inc. All rights reserved.

Quality Scalability Aware Watermarking for Visual Content.

PubMed

Bhowmik, Deepayan; Abhayaratne, Charith

2016-11-01

Scalable coding-based content adaptation poses serious challenges to traditional watermarking algorithms, which do not consider the scalable coding structure and hence cannot guarantee correct watermark extraction in media consumption chain. In this paper, we propose a novel concept of scalable blind watermarking that ensures more robust watermark extraction at various compression ratios while not effecting the visual quality of host media. The proposed algorithm generates scalable and robust watermarked image code-stream that allows the user to constrain embedding distortion for target content adaptations. The watermarked image code-stream consists of hierarchically nested joint distortion-robustness coding atoms. The code-stream is generated by proposing a new wavelet domain blind watermarking algorithm guided by a quantization based binary tree. The code-stream can be truncated at any distortion-robustness atom to generate the watermarked image with the desired distortion-robustness requirements. A blind extractor is capable of extracting watermark data from the watermarked images. The algorithm is further extended to incorporate a bit-plane discarding-based quantization model used in scalable coding-based content adaptation, e.g., JPEG2000. This improves the robustness against quality scalability of JPEG2000 compression. The simulation results verify the feasibility of the proposed concept, its applications, and its improved robustness against quality scalable content adaptation. Our proposed algorithm also outperforms existing methods showing 35% improvement. In terms of robustness to quality scalable video content adaptation using Motion JPEG2000 and wavelet-based scalable video coding, the proposed method shows major improvement for video watermarking.

Virtual file system on NoSQL for processing high volumes of HL7 messages.

PubMed

Kimura, Eizen; Ishihara, Ken

2015-01-01

The Standardized Structured Medical Information Exchange (SS-MIX) is intended to be the standard repository for HL7 messages that depend on a local file system. However, its scalability is limited. We implemented a virtual file system using NoSQL to incorporate modern computing technology into SS-MIX and allow the system to integrate local patient IDs from different healthcare systems into a universal system. We discuss its implementation using the database MongoDB and describe its performance in a case study.

Thermodynamic effects of single-qubit operations in silicon-based quantum computing

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

Lougovski, Pavel; Peters, Nicholas A.

Silicon-based quantum logic is a promising technology to implement universal quantum computing. It is widely believed that a millikelvin cryogenic environment will be necessary to accommodate silicon-based qubits. This prompts a question of the ultimate scalability of the technology due to finite cooling capacity of refrigeration systems. In this work, we answer this question by studying energy dissipation due to interactions between nuclear spin impurities and qubit control pulses. Furthermore, we demonstrate that this interaction constrains the sustainable number of single-qubit operations per second for a given cooling capacity.

Editorial: from plant biotechnology to bio-based products.

PubMed

Stöger, Eva

2013-10-01

From plant biotechnology to bio-based products - this Special Issue of Biotechnology Journal is dedicated to plant biotechnology and is edited by Prof. Eva Stöger (University of Natural Resources and Life Sciences, Vienna, Austria). The Special Issue covers a wide range of topics in plant biotechnology, including metabolic engineering of biosynthesis pathways in plants; taking advantage of the scalability of the plant system for the production of innovative materials; as well as the regulatory challenges and society acceptance of plant biotechnology. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Thermodynamic effects of single-qubit operations in silicon-based quantum computing

DOE PAGES

Lougovski, Pavel; Peters, Nicholas A.

2018-05-21

Silicon-based quantum logic is a promising technology to implement universal quantum computing. It is widely believed that a millikelvin cryogenic environment will be necessary to accommodate silicon-based qubits. This prompts a question of the ultimate scalability of the technology due to finite cooling capacity of refrigeration systems. In this work, we answer this question by studying energy dissipation due to interactions between nuclear spin impurities and qubit control pulses. Furthermore, we demonstrate that this interaction constrains the sustainable number of single-qubit operations per second for a given cooling capacity.

Optimal entangling operations between deterministic blocks of qubits encoded into single photons

NASA Astrophysics Data System (ADS)

Smith, Jake A.; Kaplan, Lev

2018-01-01

Here, we numerically simulate probabilistic elementary entangling operations between rail-encoded photons for the purpose of scalable universal quantum computation or communication. We propose grouping logical qubits into single-photon blocks wherein single-qubit rotations and the controlled-not (cnot) gate are fully deterministic and simple to implement. Interblock communication is then allowed through said probabilistic entangling operations. We find a promising trend in the increasing probability of successful interblock communication as we increase the number of optical modes operated on by our elementary entangling operations.

Head-to-Head Comparison of Chest X-Ray/Head and Neck MRI, Chest CT/Head and Neck MRI, and 18F-FDG PET/CT for Detection of Distant Metastases and Synchronous Cancer in Oral, Pharyngeal, and Laryngeal Cancer.

PubMed

Rohde, Max; Nielsen, Anne L; Johansen, Jørgen; Sørensen, Jens A; Nguyen, Nina; Diaz, Anabel; Nielsen, Mie K; Asmussen, Jon T; Christiansen, Janus M; Gerke, Oke; Thomassen, Anders; Alavi, Abass; Høilund-Carlsen, Poul Flemming; Godballe, Christian

2017-12-01

The purpose of this study was to determine the detection rate of distant metastasis and synchronous cancer, comparing clinically used imaging strategies based on chest x-ray + head and neck MRI (CXR/MRI) and chest CT + head and neck MRI (CHCT/MRI) with 18 F-FDG PET/CT upfront in the diagnostic workup of patients with oral, pharyngeal, or laryngeal cancer. Methods: This was a prospective cohort study based on paired data. Consecutive patients with histologically verified primary head and squamous cell carcinoma at Odense University Hospital from September 2013 to March 2016 were considered for the study. Included patients underwent CXR/MRI and CHCT/MRI as well as PET/CT on the same day and before biopsy. Scans were read masked by separate teams of experienced nuclear physicians or radiologists. The true detection rate of distant metastasis and synchronous cancer was assessed for CXR/MRI, CHCT/MRI, and PET/CT. Results: A total of 307 patients were included. CXR/MRI correctly detected 3 (1%) patients with distant metastasis, CHCT/MRI detected 11 (4%) patients, and PET/CT detected 18 (6%) patients. The absolute differences of 5% and 2%, respectively, were statistically significant in favor of PET/CT. Also, PET/CT correctly detected 25 (8%) synchronous cancers, which was significantly more than CXR/MRI (3 patients, 1%) and CHCT/MRI (6 patients, 2%). The true detection rate of distant metastasis or synchronous cancer with PET/CT was 13% (40 patients), which was significantly higher than 2% (6 patients) for CXR/MRI and 6% (17 patients) for CHCT/MRI. Conclusion: A clinical imaging strategy based on PET/CT demonstrated a significantly higher detection rate of distant metastasis or synchronous cancer than strategies in current clinical imaging guidelines, of which European ones primarily recommend CXR/MRI, whereas U.S. guidelines preferably point to CHCT/MRI in patients with head and neck squamous cell carcinoma. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

fastBMA: scalable network inference and transitive reduction.

PubMed

Hung, Ling-Hong; Shi, Kaiyuan; Wu, Migao; Young, William Chad; Raftery, Adrian E; Yeung, Ka Yee

2017-10-01

Inferring genetic networks from genome-wide expression data is extremely demanding computationally. We have developed fastBMA, a distributed, parallel, and scalable implementation of Bayesian model averaging (BMA) for this purpose. fastBMA also includes a computationally efficient module for eliminating redundant indirect edges in the network by mapping the transitive reduction to an easily solved shortest-path problem. We evaluated the performance of fastBMA on synthetic data and experimental genome-wide time series yeast and human datasets. When using a single CPU core, fastBMA is up to 100 times faster than the next fastest method, LASSO, with increased accuracy. It is a memory-efficient, parallel, and distributed application that scales to human genome-wide expression data. A 10 000-gene regulation network can be obtained in a matter of hours using a 32-core cloud cluster (2 nodes of 16 cores). fastBMA is a significant improvement over its predecessor ScanBMA. It is more accurate and orders of magnitude faster than other fast network inference methods such as the 1 based on LASSO. The improved scalability allows it to calculate networks from genome scale data in a reasonable time frame. The transitive reduction method can improve accuracy in denser networks. fastBMA is available as code (M.I.T. license) from GitHub (https://github.com/lhhunghimself/fastBMA), as part of the updated networkBMA Bioconductor package (https://www.bioconductor.org/packages/release/bioc/html/networkBMA.html) and as ready-to-deploy Docker images (https://hub.docker.com/r/biodepot/fastbma/). © The Authors 2017. Published by Oxford University Press.

Adaptive format conversion for scalable video coding

NASA Astrophysics Data System (ADS)

Wan, Wade K.; Lim, Jae S.

2001-12-01

The enhancement layer in many scalable coding algorithms is composed of residual coding information. There is another type of information that can be transmitted instead of (or in addition to) residual coding. Since the encoder has access to the original sequence, it can utilize adaptive format conversion (AFC) to generate the enhancement layer and transmit the different format conversion methods as enhancement data. This paper investigates the use of adaptive format conversion information as enhancement data in scalable video coding. Experimental results are shown for a wide range of base layer qualities and enhancement bitrates to determine when AFC can improve video scalability. Since the parameters needed for AFC are small compared to residual coding, AFC can provide video scalability at low enhancement layer bitrates that are not possible with residual coding. In addition, AFC can also be used in addition to residual coding to improve video scalability at higher enhancement layer bitrates. Adaptive format conversion has not been studied in detail, but many scalable applications may benefit from it. An example of an application that AFC is well-suited for is the migration path for digital television where AFC can provide immediate video scalability as well as assist future migrations.

Realistic Clocks for a Universe Without Time

NASA Astrophysics Data System (ADS)

Bryan, K. L. H.; Medved, A. J. M.

2018-01-01

There are a number of problematic features within the current treatment of time in physical theories, including the "timelessness" of the Universe as encapsulated by the Wheeler-DeWitt equation. This paper considers one particular investigation into resolving this issue; a conditional probability interpretation that was first proposed by Page and Wooters. Those authors addressed the apparent timelessness by subdividing a faux Universe into two entangled parts, "the clock" and "the remainder of the Universe", and then synchronizing the effective dynamics of the two subsystems by way of conditional probabilities. The current treatment focuses on the possibility of using a (somewhat) realistic clock system; namely, a coherent-state description of a damped harmonic oscillator. This clock proves to be consistent with the conditional probability interpretation; in particular, a standard evolution operator is identified with the position of the clock playing the role of time for the rest of the Universe. Restrictions on the damping factor are determined and, perhaps contrary to expectations, the optimal choice of clock is not necessarily one of minimal damping.

Getting the Command and Control Right: A Vietnam Case Study

DTIC Science & Technology

2013-05-23

characteristics of universality. Although the term operational art is relatively new to military doctrine, the concept of synchronization, which...OPERATION URGENT FURY in Granada and while conducting military intervention in Lebanon. Military actions in Granada and Lebanon occurred in 1983. For more...Asia were General John K. Waters , commander of U.S. Army Pacific (USARPAC), General Hunter Harris Jr., Commander-in-Chief Pacific Air Force (CINCPACAF

Cumulative Reports and Publications through December 31, 1990.

DTIC Science & Technology

1991-02-01

visiting scientists from universities and industry who have resident appointments for limited periods of time , and by consultants. Members of NASA’s...David M.: The cost of conservative synchronization in parallel discrete event simula- tions. ICASE Report No. 90-20, May 9, 1990, 31 pages. Submitted...Computing Conference, Charleston, South Carolina, Vol. II, pp. 1028-1037, April 1990. Saltz, Joel H., Ravi Mirchandaney and Kay Crowley: Run- time

MILITARY OPERATIONS IN THE INFORMATION AGE: PUTTING THE COGNITIVE DOMAIN ON TOP

DTIC Science & Technology

2017-04-06

i AIR WAR COLLEGE AIR UNIVERSITY MILITARY OPERATIONS IN THE INFORMATION AGE: PUTTING THE COGNITIVE DOMAIN ON TOP by Sidney A. Connor...in the Information Age: Putting the Cognitive Domain on Top focuses on the application of information to influence combined and synchronized with the...kinetic component of military power as the essence of information age warfare. In the information age, the proliferation of cell phone and

Sonic boom measurement test plan for Space Shuttle STS-3 reentry

NASA Technical Reports Server (NTRS)

Henderson, H. R.

1982-01-01

The lateral area from the reentry ground track affected by sonic boom overpressure levels is determined. Four data acquisition stations are deployed laterally to the STS-3 reentry flight track. These stations provide six intermediate band FM channels of sonic boom data, universal time synchronization, and voice annotation. All measurements are correlated with the vehicle reentry flight track information along with atmospheric and vehicle operation conditions.

All chain Loran-C time synchronization

NASA Technical Reports Server (NTRS)

Sherman, H. T.

1973-01-01

A program is in progress to implement coordinated universal time (UTC) synchronization on all Loran-C transmissions. The present capability is limited to five Loran-C chains in which the tolerance is twenty-five microseconds with respect to UTC. Upon completion of the program, the transmissions of all Loran-C chains will be maintained within five microseconds of UTC. The improvement plan consists of equipping selected Loran-C transmitting stations for greater precision of frequency standard adjustment and improved monitoring capability. External time monitor stations will utilize television time transfer techniques with nearby SATCOM terminals where practicable, thus providing the requisite traceability to the Naval Observatory. The monitor equipment groups and the interrelationships with the ground station equipment are discussed. After a brief review of control doctrine, forth-coming improvements to transmitting stations and how the time monitor and navigation equipments will complement each other resulting in improved service to all users of the Loran-C system are described.

Synchrony, Weather, and Cycles in Southern Pine Beetle (Coleoptera: Curculionidae).

PubMed

Reeve, John D

2018-02-08

Spatial synchrony and cycles are common features of forest insect pests, but are often studied as separate phenomenon. Using time series of timber damage caused by Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae) (southern pine beetle) in 10 states within the southern United States, this study examines synchrony in D. frontalis abundance, the synchronizing effects of temperature extremes, and the evidence for shared cycles among state populations. Cross-correlation and cluster analyses are used to quantify synchrony across a range of geographic distances and to identify groups of states with synchronous dynamics. Similar techniques are used to quantify spatial synchrony in temperature extremes and to examine their relationship to D. frontalis fluctuations. Cross-wavelet analysis is then used to examine pairs of time series for shared cycles. These analyses suggest there is substantial synchrony among states in D. frontalis fluctuations, and there are regional groups of states with similar dynamics. Synchrony in D. frontalis fluctuations also appears related to spatial synchrony in summer and winter temperature extremes. The cross-wavelet results suggest that D. frontalis dynamics may differ among regions and are not stationary. Significant oscillations were present in some states over certain time intervals, suggesting an endogenous feedback mechanism. Management of D. frontalis outbreaks could potentially benefit from a multistate regional approach because populations are synchronous on this level. Extreme summer temperatures are likely to become the most important synchronizing agent due to climate change. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Aggressive intrahepatic therapies for synchronous hepatocellular carcinoma with pulmonary metastasis.

PubMed

Hu, Z; Huang, P; Zhou, Z; Li, W; Xu, J; Xu, K; Wang, J; Zhang, H

2018-06-01

Prognosis of synchronous hepatocellular carcinoma (HCC) patients with pulmonary metastasis (PM) was poor, while aggressive intrahepatic therapies remained controversial. This study aimed to investigate the significance of aggressive intrahepatic therapies for synchronous PM-HCC. Synchronous PM-HCC patients were retrospectively enrolled from Sun Yat-sen Memorial Hospital of Sun Yat-sen University during January 2000 and December 2015. Univariate and multivariate analysis were performed to investigate the prognostic factors. Patients were grouped according to different HCC treatment modalities including liver resection (LR), ablation, transarterial chemoembolization (TACE), systemic therapy (ST, systemic chemotherapy or sorafenib) and supportive care (SC). Case control studies were achieved using propensity score matching (PSM) analysis to further investigate the significance of LR, ablation and TACE. Eighty-one patients were enrolled, and the median overall survival (OS) was 4.5 months. Serum alpha fetal protein (AFP) ≥ 400 ng/ml, multiple HCC lesions and no intrahepatic therapies (LR/Ablation/TACE) were inferior independent prognostic factors. Patients were divided into LR group (n = 9), Ablation/TACE group (n = 24) and ST/SC group (n = 48). After PSM analysis, survival outcome was superior in LR group compared to Ablation/TACE group (19.6 vs. 6.9 months) (p = 0.023) or ST/SC group (19.6 vs. 2.8 months) (p = 0.034), while no significant difference was found between -Ablation/TACE and ST/SC group (5.1 vs. 3.2 months) (p = 0.338). Prognosis of synchronous PM-HCC patients was poor. Serum AFP ≥ 400 ng/ml, multiple HCC lesions and no aggressive intrahepatic therapies were inferior prognostic factors. LR might provide survival benefits in well-selected patients, while the significance of ablation or TACE remained to be further investigated.

A transparently scalable visualization architecture for exploring the universe.

PubMed

Fu, Chi-Wing; Hanson, Andrew J

2007-01-01

Modern astronomical instruments produce enormous amounts of three-dimensional data describing the physical Universe. The currently available data sets range from the solar system to nearby stars and portions of the Milky Way Galaxy, including the interstellar medium and some extrasolar planets, and extend out to include galaxies billions of light years away. Because of its gigantic scale and the fact that it is dominated by empty space, modeling and rendering the Universe is very different from modeling and rendering ordinary three-dimensional virtual worlds at human scales. Our purpose is to introduce a comprehensive approach to an architecture solving this visualization problem that encompasses the entire Universe while seeking to be as scale-neutral as possible. One key element is the representation of model-rendering procedures using power scaled coordinates (PSC), along with various PSC-based techniques that we have devised to generalize and optimize the conventional graphics framework to the scale domains of astronomical visualization. Employing this architecture, we have developed an assortment of scale-independent modeling and rendering methods for a large variety of astronomical models, and have demonstrated scale-insensitive interactive visualizations of the physical Universe covering scales ranging from human scale to the Earth, to the solar system, to the Milky Way Galaxy, and to the entire observable Universe.

Addressable single-spin control in multiple quantum dots coupled in series

NASA Astrophysics Data System (ADS)

Nakajima, Takashi

2015-03-01

Electron spin in semiconductor quantum dots (QDs) is promising building block of quantum computers for its controllability and potential scalability. Recent experiments on GaAs QDs have demonstrated necessary ingredients of universal quantum gate operations: single-spin rotations by electron spin resonance (ESR) which is virtually free from the effect of nuclear spin fluctuation, and pulsed control of two-spin entanglement. The scalability of this architecture, however, has remained to be demonstrated in the real world. In this talk, we will present our recent results on implementing single-spin-based qubits in triple, quadruple, and quintuple QDs based on a series coupled architecture defined by gate electrodes. Deterministic initialization of individual spin states and spin-state readout were performed by the pulse operation of detuning between two neighboring QDs. The spin state was coherently manipulated by ESR, where each spin in different QDs is addressed by the shift of the resonance frequency due to the inhomogeneous magnetic field induced by the micro magnet deposited on top of the QDs. Control of two-spin entanglement was also demonstrated. We will discuss key issues for implementing quantum algorithms based on three or more qubits, including the effect of a nuclear spin bath, single-shot readout fidelity, and tuning of multiple qubit devices. Our approaches to these issues will be also presented. This research is supported by Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST) from JSPS, IARPA project ``Multi-Qubit Coherent Operations'' through Copenhagen University, and Grant-in-Aid for Scientific Research from JSPS.

CMS users data management service integration and first experiences with its NoSQL data storage

NASA Astrophysics Data System (ADS)

Riahi, H.; Spiga, D.; Boccali, T.; Ciangottini, D.; Cinquilli, M.; Hernàndez, J. M.; Konstantinov, P.; Mascheroni, M.; Santocchia, A.

2014-06-01

The distributed data analysis workflow in CMS assumes that jobs run in a different location to where their results are finally stored. Typically the user outputs must be transferred from one site to another by a dedicated CMS service, AsyncStageOut. This new service is originally developed to address the inefficiency in using the CMS computing resources when transferring the analysis job outputs, synchronously, once they are produced in the job execution node to the remote site. The AsyncStageOut is designed as a thin application relying only on the NoSQL database (CouchDB) as input and data storage. It has progressed from a limited prototype to a highly adaptable service which manages and monitors the whole user files steps, namely file transfer and publication. The AsyncStageOut is integrated with the Common CMS/Atlas Analysis Framework. It foresees the management of nearly nearly 200k users' files per day of close to 1000 individual users per month with minimal delays, and providing a real time monitoring and reports to users and service operators, while being highly available. The associated data volume represents a new set of challenges in the areas of database scalability and service performance and efficiency. In this paper, we present an overview of the AsyncStageOut model and the integration strategy with the Common Analysis Framework. The motivations for using the NoSQL technology are also presented, as well as data design and the techniques used for efficient indexing and monitoring of the data. We describe deployment model for the high availability and scalability of the service. We also discuss the hardware requirements and the results achieved as they were determined by testing with actual data and realistic loads during the commissioning and the initial production phase with the Common Analysis Framework.

Synchronous fluorescence spectroscopy of colon neoplasia

NASA Astrophysics Data System (ADS)

Borisova, Ekaterina; Semyachkina-Glushkovskaya, Oxana; Genova, Tsanislava; Penkov, Nikolay; Terziev, Ivan; Vladimirov, Borislav; Avramov, Latchezar

2017-03-01

Synchronous fluorescence spectroscopy (SFS) is a steady-state approach that we used for evaluation of specific fluorescence characteristics of cancerous colorectal tissues. SFS allow narrowing of the fluorescence spectra received, which increase the spectral resolution and improve the analysis of the fluorescence origin in such complex objects, such as biological tissues. In our study we investigate the characteristic differences, with diagnostic meaning, in the synchronous fluorescence spectra (SFS) of cancerous and healthy colorectal tissues ex vivo using a spectrofluorimeter FluoroLog3 (HORIBA, JobinYvon, France) for obtaining of the SFS data in a broad spectral range (300-800 nm) using excitation in the range of 280-440 nm with a delta lambda between 0 and 200 nm with a 10 nm step between scanning excitation and emission data. The procedure of obtaining the investigated samples ex vivo includes their excision during surgery for removal of neoplasia lesions. After the surgical removal biological samples are transported in isothermal conditions and safekeeping solution from the hospital to the spectral laboratory, where their spectral properties were investigated. All patients received and signed written informed consent and this research is approved by Ethics committee of University Hospital "Tsaritsa Yoanna", Sofia. Histological analysis was used as "gold standard" for evaluation of tissue samples and comparison of the spectral data received.

That's not quite me: limb ownership encoding in the brain.

PubMed

Limanowski, Jakub; Blankenburg, Felix

2016-07-01

With congruent stimulation of one's limb together with a fake counterpart, an illusory self-attribution of the fake limb can be induced. Such illusions have brought profound insights into the cognitive and neuronal mechanisms underlying temporary changes in body representation, but to put them in perspective, they need to be compared with ownership as experienced for one's real body. We used functional magnetic resonance imaging (fMRI) to compare the neuronal correlates of touch under different degrees of body ownership. Participants' left and right arms were stimulated either alone or together with a fake counterpart while this stimulation was synchronous, ambiguous or asynchronous. Synchronous stimulation induced illusory fake arm ownership, but the brain still differentiated between touch to one's real arm and to an illusory 'owned' arm: the degree of arm ownership was encoded positively by activity in the ventromedial prefrontal cortex and lateral occipitotemporal cortex and negatively in the temporoparietal cortex. Conversely, the ventral premotor cortex responded more strongly to synchronous stimulation compared with asynchronous stimulation and with real arm only stimulation. These results offer new insights into the differential representation of the real body vs a body that is temporarily self-attributed following the resolution of multisensory conflict. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Protecting privacy in a clinical data warehouse.

PubMed

Kong, Guilan; Xiao, Zhichun

2015-06-01

Peking University has several prestigious teaching hospitals in China. To make secondary use of massive medical data for research purposes, construction of a clinical data warehouse is imperative in Peking University. However, a big concern for clinical data warehouse construction is how to protect patient privacy. In this project, we propose to use a combination of symmetric block ciphers, asymmetric ciphers, and cryptographic hashing algorithms to protect patient privacy information. The novelty of our privacy protection approach lies in message-level data encryption, the key caching system, and the cryptographic key management system. The proposed privacy protection approach is scalable to clinical data warehouse construction with any size of medical data. With the composite privacy protection approach, the clinical data warehouse can be secure enough to keep the confidential data from leaking to the outside world. © The Author(s) 2014.

Universal blind quantum computation for hybrid system

NASA Astrophysics Data System (ADS)

Huang, He-Liang; Bao, Wan-Su; Li, Tan; Li, Feng-Guang; Fu, Xiang-Qun; Zhang, Shuo; Zhang, Hai-Long; Wang, Xiang

2017-08-01

As progress on the development of building quantum computer continues to advance, first-generation practical quantum computers will be available for ordinary users in the cloud style similar to IBM's Quantum Experience nowadays. Clients can remotely access the quantum servers using some simple devices. In such a situation, it is of prime importance to keep the security of the client's information. Blind quantum computation protocols enable a client with limited quantum technology to delegate her quantum computation to a quantum server without leaking any privacy. To date, blind quantum computation has been considered only for an individual quantum system. However, practical universal quantum computer is likely to be a hybrid system. Here, we take the first step to construct a framework of blind quantum computation for the hybrid system, which provides a more feasible way for scalable blind quantum computation.

Automatic provisioning, deployment and orchestration for load-balancing THREDDS instances

NASA Astrophysics Data System (ADS)

Cofino, A. S.; Fernández-Tejería, S.; Kershaw, P.; Cimadevilla, E.; Petri, R.; Pryor, M.; Stephens, A.; Herrera, S.

2017-12-01

THREDDS is a widely used web server to provide to different scientific communities with data access and discovery. Due to THREDDS's lack of horizontal scalability and automatic configuration management and deployment, this service usually deals with service downtimes and time consuming configuration tasks, mainly when an intensive use is done as is usual within the scientific community (e.g. climate). Instead of the typical installation and configuration of a single or multiple independent THREDDS servers, manually configured, this work presents an automatic provisioning, deployment and orchestration cluster of THREDDS servers. This solution it's based on Ansible playbooks, used to control automatically the deployment and configuration setup on a infrastructure and to manage the datasets available in THREDDS instances. The playbooks are based on modules (or roles) of different backends and frontends load-balancing setups and solutions. The frontend load-balancing system enables horizontal scalability by delegating requests to backend workers, consisting in a variable number of instances for the THREDDS server. This implementation allows to configure different infrastructure and deployment scenario setups, as more workers are easily added to the cluster by simply declaring them as Ansible variables and executing the playbooks, and also provides fault-tolerance and better reliability since if any of the workers fail another instance of the cluster can take over it. In order to test the solution proposed, two real scenarios are analyzed in this contribution: The JASMIN Group Workspaces at CEDA and the User Data Gateway (UDG) at the Data Climate Service from the University of Cantabria. On the one hand, the proposed configuration has provided CEDA with a higher level and more scalable Group Workspaces (GWS) service than the previous one based on Unix permissions, improving also the data discovery and data access experience. On the other hand, the UDG has improved its scalability by allowing requests to be distributed to the backend workers instead of being served by a unique THREDDS worker. As a conclusion the proposed configuration supposes a significant improvement with respect to configurations based on non-collaborative THREDDS' instances.

Building a Community Infrastructure for Scalable On-Line Performance Analysis Tools around Open|Speedshop

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

Miller, Barton

2014-06-30

Peta-scale computing environments pose significant challenges for both system and application developers and addressing them required more than simply scaling up existing tera-scale solutions. Performance analysis tools play an important role in gaining this understanding, but previous monolithic tools with fixed feature sets have not sufficed. Instead, this project worked on the design, implementation, and evaluation of a general, flexible tool infrastructure supporting the construction of performance tools as “pipelines” of high-quality tool building blocks. These tool building blocks provide common performance tool functionality, and are designed for scalability, lightweight data acquisition and analysis, and interoperability. For this project, wemore » built on Open|SpeedShop, a modular and extensible open source performance analysis tool set. The design and implementation of such a general and reusable infrastructure targeted for petascale systems required us to address several challenging research issues. All components needed to be designed for scale, a task made more difficult by the need to provide general modules. The infrastructure needed to support online data aggregation to cope with the large amounts of performance and debugging data. We needed to be able to map any combination of tool components to each target architecture. And we needed to design interoperable tool APIs and workflows that were concrete enough to support the required functionality, yet provide the necessary flexibility to address a wide range of tools. A major result of this project is the ability to use this scalable infrastructure to quickly create tools that match with a machine architecture and a performance problem that needs to be understood. Another benefit is the ability for application engineers to use the highly scalable, interoperable version of Open|SpeedShop, which are reassembled from the tool building blocks into a flexible, multi-user interface set of tools. This set of tools targeted at Office of Science Leadership Class computer systems and selected Office of Science application codes. We describe the contributions made by the team at the University of Wisconsin. The project built on the efforts in Open|SpeedShop funded by DOE/NNSA and the DOE/NNSA Tri-Lab community, extended Open|Speedshop to the Office of Science Leadership Class Computing Facilities, and addressed new challenges found on these cutting edge systems. Work done under this project at Wisconsin can be divided into two categories, new algorithms and techniques for debugging, and foundation infrastructure work on our Dyninst binary analysis and instrumentation toolkits and MRNet scalability infrastructure.« less

Temperature as a universal resetting cue for mammalian circadian oscillators

PubMed Central

Buhr, Ethan D.; Yoo, Seung-Hee; Takahashi, Joseph S.

2011-01-01

Environmental temperature cycles are a universal entraining cue for all circadian systems at the organismal level with the exception of homeothermic vertebrates. We report here that resistance to temperature entrainment is a property of the suprachiasmatic nucleus (SCN) network and is not a cell autonomous property of mammalian clocks. This differential sensitivity to temperature allows the SCN to drive circadian rhythms in body temperature which can then act as a universal cue for the entrainment of cell autonomous oscillators throughout the body. Pharmacological experiments show that network interactions in the SCN are required for temperature resistance and that the heat shock pathway is integral to temperature resetting and temperature compensation in mammalian cells. These results suggest that the evolutionarily ancient temperature resetting response can be utilized in homeothermic animals to enhance internal circadian synchronization. PMID:20947768

Temperature as a universal resetting cue for mammalian circadian oscillators.

PubMed

Buhr, Ethan D; Yoo, Seung-Hee; Takahashi, Joseph S

2010-10-15

Environmental temperature cycles are a universal entraining cue for all circadian systems at the organismal level with the exception of homeothermic vertebrates. We report here that resistance to temperature entrainment is a property of the suprachiasmatic nucleus (SCN) network and is not a cell-autonomous property of mammalian clocks. This differential sensitivity to temperature allows the SCN to drive circadian rhythms in body temperature, which can then act as a universal cue for the entrainment of cell-autonomous oscillators throughout the body. Pharmacological experiments show that network interactions in the SCN are required for temperature resistance and that the heat shock pathway is integral to temperature resetting and temperature compensation in mammalian cells. These results suggest that the evolutionarily ancient temperature resetting response can be used in homeothermic animals to enhance internal circadian synchronization.

Exact Performance Analysis of Two Distributed Processes with Multiple Synchronization Points.

DTIC Science & Technology

1987-05-01

number of processes with straight-line sequences of semaphore operations . We use the geometric model for performance analysis, in contrast to proving...distribution unlimited. 4. PERFORMING’*ORGANIZATION REPORT NUMBERS) 5. MONITORING ORGANIZATION REPORT NUMB CS-TR-1845 6a. NAME OF PERFORMING ORGANIZATION 6b...OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATIO U University of Maryland (If applicable) Office of Naval Research N/A 6c. ADDRESS (City, State, and

Cyber-Physical Multi-Core Optimization for Resource and Cache Effects (C2ORES)

DTIC Science & Technology

2014-03-01

DoD-sponsored ATAACK mobile cloud testbed funded through the DURIP program, which is deployed at Virginia Tech and Vanderbilt University to conduct...0.9.2. Jug was configured to use a filesystem (network file system (nfs)) backend for locking and task synchronization. 4.1.7.2 Experiment 1...and performance-aware virtual machine placement technique that is realized as cloud infrastructure middleware. The key contributions of iPlace include

Reducing Response Time Bounds for DAG-Based Task Systems on Heterogeneous Multicore Platforms

DTIC Science & Technology

2016-01-01

synchronous parallel tasks on multicore platforms. In 25th ECRTS, 2013. [10] U. Devi. Soft Real - Time Scheduling on Multiprocessors. PhD thesis...report, Washington University in St Louis, 2014. [18] C. Liu and J. Anderson. Supporting soft real - time DAG-based sys- tems on multiprocessors with...analysis for DAG-based real - time task systems im- plemented on heterogeneous multicore platforms. The spe- cific analysis problem that is considered was

PM2006: a highly scalable urban planning management information system--Case study: Suzhou Urban Planning Bureau

NASA Astrophysics Data System (ADS)

Jing, Changfeng; Liang, Song; Ruan, Yong; Huang, Jie

2008-10-01

During the urbanization process, when facing complex requirements of city development, ever-growing urban data, rapid development of planning business and increasing planning complexity, a scalable, extensible urban planning management information system is needed urgently. PM2006 is such a system that can deal with these problems. In response to the status and problems in urban planning, the scalability and extensibility of PM2006 are introduced which can be seen as business-oriented workflow extensibility, scalability of DLL-based architecture, flexibility on platforms of GIS and database, scalability of data updating and maintenance and so on. It is verified that PM2006 system has good extensibility and scalability which can meet the requirements of all levels of administrative divisions and can adapt to ever-growing changes in urban planning business. At the end of this paper, the application of PM2006 in Urban Planning Bureau of Suzhou city is described.

An Intelligent Sensor Array Distributed System for Vibration Analysis and Acoustic Noise Characterization of a Linear Switched Reluctance Actuator

PubMed Central

Salvado, José; Espírito-Santo, António; Calado, Maria

2012-01-01

This paper proposes a distributed system for analysis and monitoring (DSAM) of vibrations and acoustic noise, which consists of an array of intelligent modules, sensor modules, communication bus and a host PC acting as data center. The main advantages of the DSAM are its modularity, scalability, and flexibility for use of different type of sensors/transducers, with analog or digital outputs, and for signals of different nature. Its final cost is also significantly lower than other available commercial solutions. The system is reconfigurable, can operate either with synchronous or asynchronous modes, with programmable sampling frequencies, 8-bit or 12-bit resolution and a memory buffer of 15 kbyte. It allows real-time data-acquisition for signals of different nature, in applications that require a large number of sensors, thus it is suited for monitoring of vibrations in Linear Switched Reluctance Actuators (LSRAs). The acquired data allows the full characterization of the LSRA in terms of its response to vibrations of structural origins, and the vibrations and acoustic noise emitted under normal operation. The DSAM can also be used for electrical machine condition monitoring, machine fault diagnosis, structural characterization and monitoring, among other applications. PMID:22969364

Creating a process for incorporating epidemiological modelling into outbreak management decisions.

PubMed

Akselrod, Hana; Mercon, Monica; Kirkeby Risoe, Petter; Schlegelmilch, Jeffrey; McGovern, Joanne; Bogucki, Sandy

2012-01-01

Modern computational models of infectious diseases greatly enhance our ability to understand new infectious threats and assess the effects of different interventions. The recently-released CDC Framework for Preventing Infectious Diseases calls for increased use of predictive modelling of epidemic emergence for public health preparedness. Currently, the utility of these technologies in preparedness and response to outbreaks is limited by gaps between modelling output and information requirements for incident management. The authors propose an operational structure that will facilitate integration of modelling capabilities into action planning for outbreak management, using the Incident Command System (ICS) and Synchronization Matrix framework. It is designed to be adaptable and scalable for use by state and local planners under the National Response Framework (NRF) and Emergency Support Function #8 (ESF-8). Specific epidemiological modelling requirements are described, and integrated with the core processes for public health emergency decision support. These methods can be used in checklist format to align prospective or real-time modelling output with anticipated decision points, and guide strategic situational assessments at the community level. It is anticipated that formalising these processes will facilitate translation of the CDC's policy guidance from theory to practice during public health emergencies involving infectious outbreaks.

An empirical evaluation of lightweight random walk based routing protocol in duty cycle aware wireless sensor networks.

PubMed

Mian, Adnan Noor; Fatima, Mehwish; Khan, Raees; Prakash, Ravi

2014-01-01

Energy efficiency is an important design paradigm in Wireless Sensor Networks (WSNs) and its consumption in dynamic environment is even more critical. Duty cycling of sensor nodes is used to address the energy consumption problem. However, along with advantages, duty cycle aware networks introduce some complexities like synchronization and latency. Due to their inherent characteristics, many traditional routing protocols show low performance in densely deployed WSNs with duty cycle awareness, when sensor nodes are supposed to have high mobility. In this paper we first present a three messages exchange Lightweight Random Walk Routing (LRWR) protocol and then evaluate its performance in WSNs for routing low data rate packets. Through NS-2 based simulations, we examine the LRWR protocol by comparing it with DYMO, a widely used WSN protocol, in both static and dynamic environments with varying duty cycles, assuming the standard IEEE 802.15.4 in lower layers. Results for the three metrics, that is, reliability, end-to-end delay, and energy consumption, show that LRWR protocol outperforms DYMO in scalability, mobility, and robustness, showing this protocol as a suitable choice in low duty cycle and dense WSNs.

Sublattice parallel replica dynamics.

PubMed

Martínez, Enrique; Uberuaga, Blas P; Voter, Arthur F

2014-06-01

Exascale computing presents a challenge for the scientific community as new algorithms must be developed to take full advantage of the new computing paradigm. Atomistic simulation methods that offer full fidelity to the underlying potential, i.e., molecular dynamics (MD) and parallel replica dynamics, fail to use the whole machine speedup, leaving a region in time and sample size space that is unattainable with current algorithms. In this paper, we present an extension of the parallel replica dynamics algorithm [A. F. Voter, Phys. Rev. B 57, R13985 (1998)] by combining it with the synchronous sublattice approach of Shim and Amar [ and , Phys. Rev. B 71, 125432 (2005)], thereby exploiting event locality to improve the algorithm scalability. This algorithm is based on a domain decomposition in which events happen independently in different regions in the sample. We develop an analytical expression for the speedup given by this sublattice parallel replica dynamics algorithm and compare it with parallel MD and traditional parallel replica dynamics. We demonstrate how this algorithm, which introduces a slight additional approximation of event locality, enables the study of physical systems unreachable with traditional methodologies and promises to better utilize the resources of current high performance and future exascale computers.

Tunable Luminescent Carbon Nanospheres with Well-Defined Nanoscale Chemistry for Synchronized Imaging and Therapy.

PubMed

Mukherjee, Prabuddha; Misra, Santosh K; Gryka, Mark C; Chang, Huei-Huei; Tiwari, Saumya; Wilson, William L; Scott, John W; Bhargava, Rohit; Pan, Dipanjan

2015-09-01

In this work, we demonstrate the significance of defined surface chemistry in synthesizing luminescent carbon nanomaterials (LCN) with the capability to perform dual functions (i.e., diagnostic imaging and therapy). The surface chemistry of LCN has been tailored to achieve two different varieties: one that has a thermoresponsive polymer and aids in the controlled delivery of drugs, and the other that has fluorescence emission both in the visible and near-infrared (NIR) region and can be explored for advanced diagnostic modes. Although these particles are synthesized using simple, yet scalable hydrothermal methods, they exhibit remarkable stability, photoluminescence and biocompatibility. The photoluminescence properties of these materials are tunable through careful choice of surface-passivating agents and can be exploited for both visible and NIR imaging. Here the synthetic strategy demonstrates the possibility to incorporate a potent antimetastatic agent for inhibiting melanomas in vitro. Since both particles are Raman active, their dispersion on skin surface is reported with Raman imaging and utilizing photoluminescence, their depth penetration is analysed using fluorescence 3D imaging. Our results indicate a new generation of tunable carbon-based probes for diagnosis, therapy or both. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Network structure of multivariate time series.

PubMed

Lacasa, Lucas; Nicosia, Vincenzo; Latora, Vito

2015-10-21

Our understanding of a variety of phenomena in physics, biology and economics crucially depends on the analysis of multivariate time series. While a wide range tools and techniques for time series analysis already exist, the increasing availability of massive data structures calls for new approaches for multidimensional signal processing. We present here a non-parametric method to analyse multivariate time series, based on the mapping of a multidimensional time series into a multilayer network, which allows to extract information on a high dimensional dynamical system through the analysis of the structure of the associated multiplex network. The method is simple to implement, general, scalable, does not require ad hoc phase space partitioning, and is thus suitable for the analysis of large, heterogeneous and non-stationary time series. We show that simple structural descriptors of the associated multiplex networks allow to extract and quantify nontrivial properties of coupled chaotic maps, including the transition between different dynamical phases and the onset of various types of synchronization. As a concrete example we then study financial time series, showing that a multiplex network analysis can efficiently discriminate crises from periods of financial stability, where standard methods based on time-series symbolization often fail.

Biomimetic Models for An Ecological Approach to Massively-Deployed Sensor Networks

NASA Technical Reports Server (NTRS)

Jones, Kennie H.; Lodding, Kenneth N.; Olariu, Stephan; Wilson, Larry; Xin, Chunsheng

2005-01-01

Promises of ubiquitous control of the physical environment by massively-deployed wireless sensor networks open avenues for new applications that will redefine the way we live and work. Due to small size and low cost of sensor devices, visionaries promise systems enabled by deployment of massive numbers of sensors ubiquitous throughout our environment working in concert. Recent research has concentrated on developing techniques for performing relatively simple tasks with minimal energy expense, assuming some form of centralized control. Unfortunately, centralized control is not conducive to parallel activities and does not scale to massive size networks. Execution of simple tasks in sparse networks will not lead to the sophisticated applications predicted. We propose a new way of looking at massively-deployed sensor networks, motivated by lessons learned from the way biological ecosystems are organized. We demonstrate that in such a model, fully distributed data aggregation can be performed in a scalable fashion in massively deployed sensor networks, where motes operate on local information, making local decisions that are aggregated across the network to achieve globally-meaningful effects. We show that such architectures may be used to facilitate communication and synchronization in a fault-tolerant manner, while balancing workload and required energy expenditure throughout the network.

Investigations into the behaviour of Plasma surrounding Pulsars: DYMPHNA3D

NASA Astrophysics Data System (ADS)

Rochford, Ronan; Mc Donald, John; Shearer, Andy

2011-08-01

We report on a new 3D fully relativistic, modular, parallel and scalable Particle-In-Cell (PIC) code currently being developed at the Computational Astrophysics Laboratory in the National University of Ireland, Galway and its initial test applications to the plasma distribution in the vicinity of a rapidly rotating neutron star. We find that Plasma remains confined by trapping surfaces close to the star as opposed to propagating to a significant portion of the light-cylinder distance as predicted in this early work. We discuss planned future modifications and applications of the developed code.

Beyond accuracy: creating interoperable and scalable text-mining web services.

PubMed

Wei, Chih-Hsuan; Leaman, Robert; Lu, Zhiyong

2016-06-15

The biomedical literature is a knowledge-rich resource and an important foundation for future research. With over 24 million articles in PubMed and an increasing growth rate, research in automated text processing is becoming increasingly important. We report here our recently developed web-based text mining services for biomedical concept recognition and normalization. Unlike most text-mining software tools, our web services integrate several state-of-the-art entity tagging systems (DNorm, GNormPlus, SR4GN, tmChem and tmVar) and offer a batch-processing mode able to process arbitrary text input (e.g. scholarly publications, patents and medical records) in multiple formats (e.g. BioC). We support multiple standards to make our service interoperable and allow simpler integration with other text-processing pipelines. To maximize scalability, we have preprocessed all PubMed articles, and use a computer cluster for processing large requests of arbitrary text. Our text-mining web service is freely available at http://www.ncbi.nlm.nih.gov/CBBresearch/Lu/Demo/tmTools/#curl : Zhiyong.Lu@nih.gov. Published by Oxford University Press 2016. This work is written by US Government employees and is in the public domain in the US.

Scalability Issues for Remote Sensing Infrastructure: A Case Study

PubMed Central

Liu, Yang; Picard, Sean; Williamson, Carey

2017-01-01

For the past decade, a team of University of Calgary researchers has operated a large “sensor Web” to collect, analyze, and share scientific data from remote measurement instruments across northern Canada. This sensor Web receives real-time data streams from over a thousand Internet-connected sensors, with a particular emphasis on environmental data (e.g., space weather, auroral phenomena, atmospheric imaging). Through research collaborations, we had the opportunity to evaluate the performance and scalability of their remote sensing infrastructure. This article reports the lessons learned from our study, which considered both data collection and data dissemination aspects of their system. On the data collection front, we used benchmarking techniques to identify and fix a performance bottleneck in the system’s memory management for TCP data streams, while also improving system efficiency on multi-core architectures. On the data dissemination front, we used passive and active network traffic measurements to identify and reduce excessive network traffic from the Web robots and JavaScript techniques used for data sharing. While our results are from one specific sensor Web system, the lessons learned may apply to other scientific Web sites with remote sensing infrastructure. PMID:28468262

Living Organisms Coupling to Electromagnetic Radiation Below Thermal Noise

NASA Astrophysics Data System (ADS)

Stolc, Viktor; Freund, Friedemann

2013-04-01

Ultralow frequency (ULF) and extremely low frequency (ELF) electromagnetic (EM) radiation is part of the natural environment. Prior to major earthquakes the local ULF and global ELF radiation field is often markedly perturbed. This has detrimental effects on living organisms. We are studying the mechanism of these effects on the biochemical, cellular and organismal levels. The transfer of electrons along the Electron Transfer Chain (ETC) controls the universal reduction-oxidation reactions that are essential for fundamental biochemical processes in living cells. In order for these processes to work properly, the ETC has to maintain some form of synchronization, or coherence with all biochemical reactions in the living cells, including energy production, RNA transcription, and DNA replication. As a consequence of this synchronization, harmful chemical conflict between the reductive and the oxidative partial reactions can be minimized or avoided. At the same time we note that the synchronization allows for a transfer of energy, coherent or interfering, via coupling to the natural ambient EM field. Extremely weak high frequency EM fields, well below the thermal noise level, tuned in frequency to the electron spins of certain steps in the ETC, have already been shown to cause aberrant cell growth and disorientation among plants and animals with respect to the magnetic and gravity vectors. We investigate EM fields over a much wider frequency range, including ULF known to be generated deep in the Earth prior to major earthquakes locally, and ELF known to be fed by lightning discharges, traveling around the globe in the cavity formed between the Earth's surface and the ionosphere. This ULF/ELF radiation can control the timing of the biochemical redox cycle and thereby have a universal effect on physiology of organisms. The timing can even have a detrimental influence, via increased oxidative damage, on the DNA replication, which controls heredity.

Production of Recombinant Adeno-associated Virus Vectors Using Suspension HEK293 Cells and Continuous Harvest of Vector From the Culture Media for GMP FIX and FLT1 Clinical Vector

PubMed Central

Grieger, Joshua C; Soltys, Stephen M; Samulski, Richard Jude

2016-01-01

Adeno-associated virus (AAV) has shown great promise as a gene therapy vector in multiple aspects of preclinical and clinical applications. Many developments including new serotypes as well as self-complementary vectors are now entering the clinic. With these ongoing vector developments, continued effort has been focused on scalable manufacturing processes that can efficiently generate high-titer, highly pure, and potent quantities of rAAV vectors. Utilizing the relatively simple and efficient transfection system of HEK293 cells as a starting point, we have successfully adapted an adherent HEK293 cell line from a qualified clinical master cell bank to grow in animal component-free suspension conditions in shaker flasks and WAVE bioreactors that allows for rapid and scalable rAAV production. Using the triple transfection method, the suspension HEK293 cell line generates greater than 1 × 105 vector genome containing particles (vg)/cell or greater than 1 × 1014 vg/l of cell culture when harvested 48 hours post-transfection. To achieve these yields, a number of variables were optimized such as selection of a compatible serum-free suspension media that supports both growth and transfection, selection of a transfection reagent, transfection conditions and cell density. A universal purification strategy, based on ion exchange chromatography methods, was also developed that results in high-purity vector preps of AAV serotypes 1–6, 8, 9 and various chimeric capsids tested. This user-friendly process can be completed within 1 week, results in high full to empty particle ratios (>90% full particles), provides postpurification yields (>1 × 1013 vg/l) and purity suitable for clinical applications and is universal with respect to all serotypes and chimeric particles. To date, this scalable manufacturing technology has been utilized to manufacture GMP phase 1 clinical AAV vectors for retinal neovascularization (AAV2), Hemophilia B (scAAV8), giant axonal neuropathy (scAAV9), and retinitis pigmentosa (AAV2), which have been administered into patients. In addition, we report a minimum of a fivefold increase in overall vector production by implementing a perfusion method that entails harvesting rAAV from the culture media at numerous time-points post-transfection. PMID:26437810

Equalizer: a scalable parallel rendering framework.

PubMed

Eilemann, Stefan; Makhinya, Maxim; Pajarola, Renato

2009-01-01

Continuing improvements in CPU and GPU performances as well as increasing multi-core processor and cluster-based parallelism demand for flexible and scalable parallel rendering solutions that can exploit multipipe hardware accelerated graphics. In fact, to achieve interactive visualization, scalable rendering systems are essential to cope with the rapid growth of data sets. However, parallel rendering systems are non-trivial to develop and often only application specific implementations have been proposed. The task of developing a scalable parallel rendering framework is even more difficult if it should be generic to support various types of data and visualization applications, and at the same time work efficiently on a cluster with distributed graphics cards. In this paper we introduce a novel system called Equalizer, a toolkit for scalable parallel rendering based on OpenGL which provides an application programming interface (API) to develop scalable graphics applications for a wide range of systems ranging from large distributed visualization clusters and multi-processor multipipe graphics systems to single-processor single-pipe desktop machines. We describe the system architecture, the basic API, discuss its advantages over previous approaches, present example configurations and usage scenarios as well as scalability results.

Evaluating Testing Strategies for Identifying Youths With HIV Infection and Linking Youths to Biomedical and Other Prevention Services

PubMed Central

Boyer, Cherrie B.; Chiaramonte, Danielle; Lindeman, Peter; Chutuape, Kate; Cooper-Walker, Bendu; Kapogiannis, Bill G.; Wilson, Craig M.; Fortenberry, J. Dennis

2017-01-01

Importance Most human immunodeficiency virus (HIV)–infected youths are unaware of their serostatus (approximately 60%) and therefore not linked to HIV medical or prevention services. The need to identify promising and scalable approaches to promote uptake of HIV testing among youths at risk is critical. Objective To evaluate a multisite HIV testing program designed to encourage localized HIV testing programs focused on self-identified sexual minority males and to link youths to appropriate prevention services after receipt of their test results. Design, Setting, and Participants Testing strategies were evaluated using an observational design during a 9-month period (June 1, 2015, through February 28, 2016). Testing strategies were implemented by 12 adolescent medicine HIV primary care programs and included targeted testing, universal testing, or a combination. Data were collected from local youth at high risk of HIV infection and, specifically, sexual minority males of color. Main Outcomes and Measures Proportion of sexual minority males and sexual minority males of color tested, proportion of previously undiagnosed HIV-positive youths identified, and rates of linkage to prevention services. Results A total of 3301 youths underwent HIV testing. Overall, 35 (3.6%) of those who underwent universal testing in primary care clinical settings, such as emergency departments and community health centers, were sexual minority males (35 [3.6%] were males of color) compared with 236 (46.7%) (201 [39.8%] were males of color) who were tested through targeted testing and 693 (37.8%) (503 [27.4%] were males of color) through combination efforts. Identification of new HIV-positive cases varied by strategy: 1 (0.1%) via universal testing, 39 (2.1%) through combination testing, and 16 (3.2%) through targeted testing. However, when targeted tests were separated from universal testing results for sites using a combined strategy, the rate of newly identified HIV-positive cases identified through universal testing decreased to 1 (0.1%). Rates of new HIV-positive cases identified through targeted testing increased to 49 (6.3%). Youths who tested through targeted testing (416 [85.1%]) were more likely to link successfully to local HIV prevention services, including preexposure prophylaxis, compared with those who underwent universal testing (328 [34.1%]). Conclusions and Relevance The findings suggest that community-based targeted approaches to HIV testing are more effective than universal screening for reaching young sexual minority males (especially males of color), identifying previously undiagnosed HIV-positive youths, and linking HIV-negative youths to relevant prevention services. Targeted, community-based HIV testing strategies hold promise as a scalable and effective means to identify high-risk youths who are unaware of their HIV status. PMID:28418524

Thermoperiodism Synchronizes Emergence in the Alfalfa Leafcutting Bee (Hymenoptera: Megachilidae).

PubMed

Yocum, George D; Rinehart, Joseph P; Yocum, Ian S; Kemp, William P; Greenlee, Kendra J

2016-02-01

Alfalfa seed production in the northwestern United States and western Canada is heavily dependent upon the pollinating services of Megachile rotundata (F.) (Hymenoptera: Megachilidae). M. rotundata females nest in cavities either naturally occurring or in artificial nesting blocks. Because of the physical nature of the nest, M. rotundata brood may have limited to no exposure to photoperiodic cues in order to regulate important circadian functions. Therefore, various thermoperiod regimes were used to characterize the possible role of thermoperiodism in synchronizing M. rotundata adult emergence. Adult emergence was monitored using a microprocessor-controlled event logger. Incubating bees under constant 29°C and darkness resulted in an arhythmic adult emergence pattern. Exposing developing M. rotundata to a thermoperiod synchronized emergence to the beginning of the thermophase and decreased the total number of days required for all adults to emerge. The amplitude of the thermoperiod regulated the timing of peak emergence in relationship to the increase in temperature. A thermoperiod amplitude of only 2°C was sufficient to synchronize peak adult emergence to take place during the rise in temperature. Increasing the amplitude of the thermoperiod to 4 or 8°C caused a positively correlated shift in peak emergence to later in the thermophase. Brood stored under constant 29°C and darkness for different durations (May or June early in the growing season or July or August late in the growing season) or under a fluctuating thermal regime (base temperature of 6°C and daily 1-h pulse of 20°C until September or November) maintained their capacity for entraining emergence timing by thermoperiodism. Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

Synchronization and anti-synchronization of a fractional order delayed memristor-based chaotic system using active control

NASA Astrophysics Data System (ADS)

Ding, Dawei; Qian, Xin; Wang, Nian; Liang, Dong

2018-05-01

In this paper, the issue of synchronization and anti-synchronization for fractional-delayed memristor-based chaotic system is studied by using active control strategy. Firstly, some explicit conditions are proposed to guarantee the synchronization and anti-synchronization of the proposed system. Secondly, the influence of order and time delay on the synchronization (anti-synchronization) is discussed. It reveals that synchronization (anti-synchronization) is faster as the order increases or the time delay decreases. Finally, some numerical simulations are presented to verify the validity of our theoretical analysis.

Active control strategy for synchronization and anti-synchronization of a fractional chaotic financial system

NASA Astrophysics Data System (ADS)

Huang, Chengdai; Cao, Jinde

2017-05-01

This paper is concerned with the issues of synchronization and anti-synchronization for fractional chaotic financial system with market confidence by taking advantage of active control approach. Some sufficient conditions are derived to guarantee the synchronization and anti-synchronization for the proposed fractional system. Moreover, the relationship between the order and synchronization(anti-synchronization) is demonstrated numerically. It reveals that synchronization(anti-synchronization) is faster as the order increases. Finally, two illustrative examples are exploited to verify the efficiency of the obtained theoretical results.

Efficient universal quantum channel simulation in IBM's cloud quantum computer

NASA Astrophysics Data System (ADS)

Wei, Shi-Jie; Xin, Tao; Long, Gui-Lu

2018-07-01

The study of quantum channels is an important field and promises a wide range of applications, because any physical process can be represented as a quantum channel that transforms an initial state into a final state. Inspired by the method of performing non-unitary operators by the linear combination of unitary operations, we proposed a quantum algorithm for the simulation of the universal single-qubit channel, described by a convex combination of "quasi-extreme" channels corresponding to four Kraus operators, and is scalable to arbitrary higher dimension. We demonstrated the whole algorithm experimentally using the universal IBM cloud-based quantum computer and studied the properties of different qubit quantum channels. We illustrated the quantum capacity of the general qubit quantum channels, which quantifies the amount of quantum information that can be protected. The behavior of quantum capacity in different channels revealed which types of noise processes can support information transmission, and which types are too destructive to protect information. There was a general agreement between the theoretical predictions and the experiments, which strongly supports our method. By realizing the arbitrary qubit channel, this work provides a universally- accepted way to explore various properties of quantum channels and novel prospect for quantum communication.

Scalability problems of simple genetic algorithms.

PubMed

Thierens, D

1999-01-01

Scalable evolutionary computation has become an intensively studied research topic in recent years. The issue of scalability is predominant in any field of algorithmic design, but it became particularly relevant for the design of competent genetic algorithms once the scalability problems of simple genetic algorithms were understood. Here we present some of the work that has aided in getting a clear insight in the scalability problems of simple genetic algorithms. Particularly, we discuss the important issue of building block mixing. We show how the need for mixing places a boundary in the GA parameter space that, together with the boundary from the schema theorem, delimits the region where the GA converges reliably to the optimum in problems of bounded difficulty. This region shrinks rapidly with increasing problem size unless the building blocks are tightly linked in the problem coding structure. In addition, we look at how straightforward extensions of the simple genetic algorithm-namely elitism, niching, and restricted mating are not significantly improving the scalability problems.

Low-complexity transcoding algorithm from H.264/AVC to SVC using data mining

NASA Astrophysics Data System (ADS)

Garrido-Cantos, Rosario; De Cock, Jan; Martínez, Jose Luis; Van Leuven, Sebastian; Cuenca, Pedro; Garrido, Antonio

2013-12-01

Nowadays, networks and terminals with diverse characteristics of bandwidth and capabilities coexist. To ensure a good quality of experience, this diverse environment demands adaptability of the video stream. In general, video contents are compressed to save storage capacity and to reduce the bandwidth required for its transmission. Therefore, if these compressed video streams were compressed using scalable video coding schemes, they would be able to adapt to those heterogeneous networks and a wide range of terminals. Since the majority of the multimedia contents are compressed using H.264/AVC, they cannot benefit from that scalability. This paper proposes a low-complexity algorithm to convert an H.264/AVC bitstream without scalability to scalable bitstreams with temporal scalability in baseline and main profiles by accelerating the mode decision task of the scalable video coding encoding stage using machine learning tools. The results show that when our technique is applied, the complexity is reduced by 87% while maintaining coding efficiency.

Toward a formal verification of a floating-point coprocessor and its composition with a central processing unit

NASA Technical Reports Server (NTRS)

Pan, Jing; Levitt, Karl N.; Cohen, Gerald C.

1991-01-01

Discussed here is work to formally specify and verify a floating point coprocessor based on the MC68881. The HOL verification system developed at Cambridge University was used. The coprocessor consists of two independent units: the bus interface unit used to communicate with the cpu and the arithmetic processing unit used to perform the actual calculation. Reasoning about the interaction and synchronization among processes using higher order logic is demonstrated.

Telemetering and telecommunications research

NASA Technical Reports Server (NTRS)

Osborne, William; Paz, Robert; Ross, Michael; Kopp, Brian; Ashley, Norm

1993-01-01

The New Mexico State University (NMSU) Center for Space Telemetering and Telecommunications systems is engaged in advanced communications systems research. Four areas of study that are being sponsored concern investigations into the use of trellis-coded modulation (TCM). In particular, two areas concentrate on carrier synchronization research in TCM M-ary phase shift key (MPSK) systems. A third research topic is the study of interference effects on TCM, while the fourth research area is in the field of concatenated TCM systems.

The role of attention and intention in synchronization to music: effects on gait.

PubMed

Leow, Li-Ann; Waclawik, Kristina; Grahn, Jessica A

2018-01-01

Anecdotal accounts suggest that individuals spontaneously synchronize their movements to the 'beat' of background music, often without intending to, and perhaps even without attending to the music at all. However, the question of whether intention and attention are necessary to synchronize to the beat remains unclear. Here, we compared whether footsteps during overground walking were synchronized to the beat when young healthy adults were explicitly instructed to synchronize (intention to synchronize), and were not instructed to synchronize (no intention) (Experiment 1: intention). We also examined whether reducing participants' attention to the music affected synchronization, again when participants were explicitly instructed to synchronize, and when they were not (Experiment 2: attention/intention). Synchronization was much less frequent when no instructions to synchronize were given. Without explicit instructions to synchronize, there was no evidence of synchronization in 60% of the trials in Experiment 1, and 43% of the trials in Experiment 2. When instructed to synchronize, only 26% of trials in Experiment 1, and 14% of trials in Experiment 2 showed no evidence of synchronization. Because walking to music alters gait, we also examined how gait kinematics changed with or without instructions to synchronize, and attention to the music was required for synchronization to occur. Instructions to synchronize elicited slower, shorter, and more variable strides than walking in silence. Reducing attention to the music did not significantly affect synchronization of footsteps to the beat, but did elicit slower gait. Thus, during walking, intention, but not attention, appears to be necessary to synchronize footsteps to the beat, and synchronization elicits slower, shorter, and more variable strides, at least in young healthy adults.

Engineering the quantum states of light in a Kerr-nonlinear resonator by two-photon driving

NASA Astrophysics Data System (ADS)

Puri, Shruti; Boutin, Samuel; Blais, Alexandre

2017-04-01

Photonic cat states stored in high-Q resonators show great promise for hardware efficient universal quantum computing. We propose an approach to efficiently prepare such cat states in a Kerr-nonlinear resonator by the use of a two-photon drive. Significantly, we show that this preparation is robust against single-photon loss. An outcome of this observation is that a two-photon drive can eliminate undesirable phase evolution induced by a Kerr nonlinearity. By exploiting the concept of transitionless quantum driving, we moreover demonstrate how non-adiabatic initialization of cat states is possible. Finally, we present a universal set of quantum logical gates that can be performed on the engineered eigenspace of such a two-photon driven resonator and discuss a possible realization using superconducting circuits. The robustness of the engineered subspace to higher-order circuit nonlinearities makes this implementation favorable for scalable quantum computation.

Demonstration of universal parametric entangling gates on a multi-qubit lattice

PubMed Central

Reagor, Matthew; Osborn, Christopher B.; Tezak, Nikolas; Staley, Alexa; Prawiroatmodjo, Guenevere; Scheer, Michael; Alidoust, Nasser; Sete, Eyob A.; Didier, Nicolas; da Silva, Marcus P.; Acala, Ezer; Angeles, Joel; Bestwick, Andrew; Block, Maxwell; Bloom, Benjamin; Bradley, Adam; Bui, Catvu; Caldwell, Shane; Capelluto, Lauren; Chilcott, Rick; Cordova, Jeff; Crossman, Genya; Curtis, Michael; Deshpande, Saniya; El Bouayadi, Tristan; Girshovich, Daniel; Hong, Sabrina; Hudson, Alex; Karalekas, Peter; Kuang, Kat; Lenihan, Michael; Manenti, Riccardo; Manning, Thomas; Marshall, Jayss; Mohan, Yuvraj; O’Brien, William; Otterbach, Johannes; Papageorge, Alexander; Paquette, Jean-Philip; Pelstring, Michael; Polloreno, Anthony; Rawat, Vijay; Ryan, Colm A.; Renzas, Russ; Rubin, Nick; Russel, Damon; Rust, Michael; Scarabelli, Diego; Selvanayagam, Michael; Sinclair, Rodney; Smith, Robert; Suska, Mark; To, Ting-Wai; Vahidpour, Mehrnoosh; Vodrahalli, Nagesh; Whyland, Tyler; Yadav, Kamal; Zeng, William; Rigetti, Chad T.

2018-01-01

We show that parametric coupling techniques can be used to generate selective entangling interactions for multi-qubit processors. By inducing coherent population exchange between adjacent qubits under frequency modulation, we implement a universal gate set for a linear array of four superconducting qubits. An average process fidelity of ℱ = 93% is estimated for three two-qubit gates via quantum process tomography. We establish the suitability of these techniques for computation by preparing a four-qubit maximally entangled state and comparing the estimated state fidelity with the expected performance of the individual entangling gates. In addition, we prepare an eight-qubit register in all possible bitstring permutations and monitor the fidelity of a two-qubit gate across one pair of these qubits. Across all these permutations, an average fidelity of ℱ = 91.6 ± 2.6% is observed. These results thus offer a path to a scalable architecture with high selectivity and low cross-talk. PMID:29423443

Improving Rural Geriatric Care Through Education: A Scalable, Collaborative Project.

PubMed

Buck, Harleah G; Kolanowski, Ann; Fick, Donna; Baronner, Lawrence

2016-07-01

HOW TO OBTAIN CONTACT HOURS BY READING THIS ISSUE Instructions: 1.2 contact hours will be awarded by Villanova University College of Nursing upon successful completion of this activity. A contact hour is a unit of measurement that denotes 60 minutes of an organized learning activity. This is a learner-based activity. Villanova University College of Nursing does not require submission of your answers to the quiz. A contact hour certificate will be awarded after you register, pay the registration fee, and complete the evaluation form online at http://goo.gl/gMfXaf. In order to obtain contact hours you must: 1. Read the article, "Improving Rural Geriatric Care Through Education: A Scalable, Collaborative Project," found on pages 306-313, carefully noting any tables and other illustrative materials that are included to enhance your knowledge and understanding of the content. Be sure to keep track of the amount of time (number of minutes) you spend reading the article and completing the quiz. 2. Read and answer each question on the quiz. After completing all of the questions, compare your answers to those provided within this issue. If you have incorrect answers, return to the article for further study. 3. Go to the Villanova website to register for contact hour credit. You will be asked to provide your name, contact information, and a VISA, MasterCard, or Discover card number for payment of the $20.00 fee. Once you complete the online evaluation, a certificate will be automatically generated. This activity is valid for continuing education credit until June 30, 2019. CONTACT HOURS This activity is co-provided by Villanova University College of Nursing and SLACK Incorporated. Villanova University College of Nursing is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's Commission on Accreditation. OBJECTIVES Describe the unique nursing challenges that occur in caring for older adults in rural areas. Discuss the Improving Rural Geriatric Care through Education (iRuGCE) project, including the facilitators and challenges to its implementation. DISCLOSURE STATEMENT Neither the planners nor the author have any conflicts of interest to disclose. Rural elders are the fastest growing segment of the U.S. population, with a projected increase of 32% in the next 20 years. Shortages in geriatric-prepared workers are particularly critical in rural areas. This article describes Improving Rural Geriatric Care through Education (iRuGCE), a feasible, scalable, and collaborative continuing education project. iRuGCE was designed to improve geriatric nursing practice. Project goals were to identify, mentor, and facilitate an RN geriatric site champion in critical access hospitals (CAHs) to complete national certification in gerontological nursing, and to design a continuing education program that met the specific needs of the CAHs via delivery of three continuing education sessions per year. Evaluation of the project is promising. Preliminary results suggest that iRuGCE has a positive effect on nurse-sensitive patient satisfaction scores, such as communication with nurses, responsiveness of hospital staff, pain management, communication about medicine, discharge information, and willingness to recommend the hospital. J Contin Educ Nurs. 2016;47(7):306-313. Copyright 2016, SLACK Incorporated.

Neutrino flavor transformation in the lepton-asymmetric universe

DOE PAGES

Johns, Lucas Andrew; Mina, Mattia; Cirigliano, Vincenzo; ...

2016-10-01

We investigate neutrino flavor transformation in the early Universe in the presence of a lepton asymmetry, focusing on a two-flavor system with 1–3 mixing parameters. We identify five distinct regimes that emerge in an approximate treatment neglecting collisions as the initial lepton asymmetry at high temperature is varied from values comparable to current constraints on the lepton number down to values at which the neutrino-neutrino forward-scattering potential is negligible. The characteristic phenomena occurring in these regimes are (1) large synchronized oscillations, (2) minimal flavor transformation, (3) asymmetric (ν- or ν¯-only) MSW, (4) partial MSW, and (5) symmetric MSW. We examinemore » our numerical results in the framework of adiabaticity, and we illustrate how they are modified by collisional damping. Lastly, we point out the existence of matter-neutrino resonances in the early Universe and show that they suffer from nonadiabaticity.« less

Neutrino flavor transformation in the lepton-asymmetric universe

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

Johns, Lucas Andrew; Mina, Mattia; Cirigliano, Vincenzo

We investigate neutrino flavor transformation in the early Universe in the presence of a lepton asymmetry, focusing on a two-flavor system with 1–3 mixing parameters. We identify five distinct regimes that emerge in an approximate treatment neglecting collisions as the initial lepton asymmetry at high temperature is varied from values comparable to current constraints on the lepton number down to values at which the neutrino-neutrino forward-scattering potential is negligible. The characteristic phenomena occurring in these regimes are (1) large synchronized oscillations, (2) minimal flavor transformation, (3) asymmetric (ν- or ν¯-only) MSW, (4) partial MSW, and (5) symmetric MSW. We examinemore » our numerical results in the framework of adiabaticity, and we illustrate how they are modified by collisional damping. Lastly, we point out the existence of matter-neutrino resonances in the early Universe and show that they suffer from nonadiabaticity.« less

Scalable Integrated Region-Based Image Retrieval Using IRM and Statistical Clustering.

ERIC Educational Resources Information Center

Wang, James Z.; Du, Yanping

Statistical clustering is critical in designing scalable image retrieval systems. This paper presents a scalable algorithm for indexing and retrieving images based on region segmentation. The method uses statistical clustering on region features and IRM (Integrated Region Matching), a measure developed to evaluate overall similarity between images…

Temporally Scalable Visual SLAM using a Reduced Pose Graph

DTIC Science & Technology

2012-05-25

m b r i d g e , m a 0 213 9 u s a — w w w. c s a i l . m i t . e d u MIT-CSAIL-TR-2012-013 May 25, 2012 Temporally Scalable Visual SLAM using a...00-00-2012 4. TITLE AND SUBTITLE Temporally Scalable Visual SLAM using a Reduced Pose Graph 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...demonstrate a system for temporally scalable visual SLAM using a reduced pose graph representation. Unlike previous visual SLAM approaches that use

A uniform approach for programming distributed heterogeneous computing systems

PubMed Central

Grasso, Ivan; Pellegrini, Simone; Cosenza, Biagio; Fahringer, Thomas

2014-01-01

Large-scale compute clusters of heterogeneous nodes equipped with multi-core CPUs and GPUs are getting increasingly popular in the scientific community. However, such systems require a combination of different programming paradigms making application development very challenging. In this article we introduce libWater, a library-based extension of the OpenCL programming model that simplifies the development of heterogeneous distributed applications. libWater consists of a simple interface, which is a transparent abstraction of the underlying distributed architecture, offering advanced features such as inter-context and inter-node device synchronization. It provides a runtime system which tracks dependency information enforced by event synchronization to dynamically build a DAG of commands, on which we automatically apply two optimizations: collective communication pattern detection and device-host-device copy removal. We assess libWater’s performance in three compute clusters available from the Vienna Scientific Cluster, the Barcelona Supercomputing Center and the University of Innsbruck, demonstrating improved performance and scaling with different test applications and configurations. PMID:25844015

Low-energy plasma observations at synchronous orbit

NASA Technical Reports Server (NTRS)

Lennartsson, W.; Reasoner, D. L.

1978-01-01

The University of California at San Diego Auroral Particles Experiment on the ATS 6 satellite in synchronous orbit has detected a low-energy plasma population which is separate and distinct from both the ring current and the plasma sheet populations. The density and temperature of this low-energy population are highly variable, with temperatures in the range kT = 1-30 eV and densities ranging from less than 1 per cu cm to more than 10 per cu cm. The occurrence of a dense low-energy plasma is most likely in the afternoon and dusk local time sectors, whereas n greater than 1 per cu cm is seen in the local night sector only during magnetically quiet periods. These observations suggest that this plasma is the outer zone of the plasmasphere. During magnetically active periods this low-energy plasma is often observed flowing sunward. In the dusk sector, strong sunward plasma flow is often observed for 1-2 hours prior to the onset of a substorm-associated particle injection.

Controlling chaos with localized heterogeneous forces in oscillator chains.

PubMed

Chacón, Ricardo

2006-10-01

The effects of decreasing the impulse transmitted by localized periodic pulses on the chaotic behavior of homogeneous chains of coupled nonlinear oscillators are studied. It is assumed that when the oscillators are driven synchronously, i.e., all driving pulses transmit the same impulse, the chains display chaotic dynamics. It is shown that decreasing the impulse transmitted by the pulses of the two free end oscillators results in regularization with the whole array exhibiting frequency synchronization, irrespective of the chain size. A maximum level of amplitude desynchrony as the pulses of the two end oscillators narrow is typically found, which is explained as the result of two competing universal mechanisms: desynchronization induced by localized heterogeneous pulses and oscillation death of the complete chain induced by drastic decreasing of the impulse transmitted by such localized pulses. These findings demonstrate that decreasing the impulse transmitted by localized external forces can suppress chaos and lead to frequency-locked states in networks of dissipative systems.

On the ability of synchronously rotating planets to support atmospheres

NASA Astrophysics Data System (ADS)

Joshi, Manoj M.; Haberle, Robert M.

1997-01-01

Planets within the habitable zones of M stars are likely to be synchronous rotators, i.e., one side is permanently illuminated while the other side is in perpetual darkness. For such planets to be habitable, horizontal atmospheric motions must be capable of transporting enough heat from the day side to the night side to prevent the atmosphere from freezing out. Simple calculations have shown that the equivalent of approximately 150 mb of CO2 is required to prevent atmospheric condensation on the dark side. We now use a 3D global circulation model in order to better assess the ability of these planets to sustain an atmosphere. The results of this work show that for an Earth-sized planet, 100 mb of CO2 is required to support an atmosphere, while 1-2 bars are sufficient to allow liquid water everywhere. Planetary systems associated with M stars should therefore not be ruled out in the search for life in the universe.

A uniform approach for programming distributed heterogeneous computing systems.

PubMed

Grasso, Ivan; Pellegrini, Simone; Cosenza, Biagio; Fahringer, Thomas

2014-12-01

Large-scale compute clusters of heterogeneous nodes equipped with multi-core CPUs and GPUs are getting increasingly popular in the scientific community. However, such systems require a combination of different programming paradigms making application development very challenging. In this article we introduce libWater, a library-based extension of the OpenCL programming model that simplifies the development of heterogeneous distributed applications. libWater consists of a simple interface, which is a transparent abstraction of the underlying distributed architecture, offering advanced features such as inter-context and inter-node device synchronization. It provides a runtime system which tracks dependency information enforced by event synchronization to dynamically build a DAG of commands, on which we automatically apply two optimizations: collective communication pattern detection and device-host-device copy removal. We assess libWater's performance in three compute clusters available from the Vienna Scientific Cluster, the Barcelona Supercomputing Center and the University of Innsbruck, demonstrating improved performance and scaling with different test applications and configurations.

Kennedy Space Center Timing and Countdown Interface to Kennedy Ground Control Subsystem

NASA Technical Reports Server (NTRS)

Olsen, James C.

2015-01-01

Kennedy Ground Control System (KGCS) engineers at the National Aeronautics and Space Administration (NASA) Kennedy Space Center (KSC) are developing a time-tagging process to enable reconstruction of the events during a launch countdown. Such a process can be useful in the case of anomalies or other situations where it is necessary to know the exact time an event occurred. It is thus critical for the timing information to be accurate. KGCS will synchronize all items with Coordinated Universal Time (UTC) obtained from the Timing and Countdown (T&CD) organization. Network Time Protocol (NTP) is the protocol currently in place for synchronizing UTC. However, NTP has a peak error that is too high for today's standards. Precision Time Protocol (PTP) is a newer protocol with a much smaller peak error. The focus of this project has been to implement a PTP solution on the network to increase timing accuracy while introducing and configuring the implementation of a firewall between T&CD and the KGCS network.

Arnold Tongues in Cell Dynamics

NASA Astrophysics Data System (ADS)

Jensen, Mogens

In a recent work with Leo Kadanoff we studied the synchronization between an internal and an external frequency. One obtains a highly structured diagram with details that in essence are related to the difference between rational and irrational number. The synchronized regions appear as Arnold tongues that widen as the coupling between the frequencies increases. Such tongues have been observed in many physical systems, like in the Libchaber convective cell in the basement of the University of Chicago. In biological systems, where oscillators appear in in a broad variety, very little research on Arnold tongues has been performed. We discuss single cell oscillating dynamics triggered by an external cytokine signal. When this signal is overlaid by an oscillating variation, the two oscillators might couple leading to Arnold tongue diagram. When the tongues overlap, the cell dynamics can shift between the tongues eventually leading to a chaotic response. We quantify such switching in single cell experiments and in model systems based on Gillespie simulations. Kadanoff session.

Collective behavior of coupled nonuniform stochastic oscillators

NASA Astrophysics Data System (ADS)

Assis, Vladimir R. V.; Copelli, Mauro

2012-02-01

Theoretical studies of synchronization are usually based on models of coupled phase oscillators which, when isolated, have constant angular frequency. Stochastic discrete versions of these uniform oscillators have also appeared in the literature, with equal transition rates among the states. Here we start from the model recently introduced by Wood et al. [K. Wood, C. Van den Broeck, R. Kawai, K. Lindenberg, Universality of synchrony: critical behavior in a discrete model of stochastic phase-coupled oscillators, Phys. Rev. Lett. 96 (2006) 145701], which has a collectively synchronized phase, and parametrically modify the phase-coupled oscillators to render them (stochastically) nonuniform. We show that, depending on the nonuniformity parameter 0≤α≤1, a mean field analysis predicts the occurrence of several phase transitions. In particular, the phase with collective oscillations is stable for the complete graph only for α≤α‧<1. At α=1 the oscillators become excitable elements and the system has an absorbing state. In the excitable regime, no collective oscillations were found in the model.

Overview of the NSTX Control System

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

P. Sichta; J. Dong; G. Oliaro

2001-12-03

The National Spherical Torus Experiment (NSTX) is an innovative magnetic fusion device that was constructed by the Princeton Plasma Physics Laboratory (PPPL) in collaboration with the Oak Ridge National Laboratory, Columbia University, and the University of Washington at Seattle. Since achieving first plasma in 1999, the device has been used for fusion research through an international collaboration of more than twenty institutions. The NSTX is operated through a collection of control systems that encompass a wide range of technology, from hardwired relay controls to real-time control systems with giga-FLOPS of capability. This paper presents a broad introduction to the controlmore » systems used on NSTX, with an emphasis on the computing controls, data acquisition, and synchronization systems.« less

The control gain region for synchronization in non-diffusively coupled complex networks

NASA Astrophysics Data System (ADS)

Gequn, Liu; Wenhui, Li; Huijie, Yang; Knowles, Gareth

2014-07-01

The control gain region for synchronization of non-diffusively coupled networks was studied with respect to three conditions: synchronization, synchronization in finite time, and synchronization in the minimum time. Based on cancellation control methodology and master stability function formalism, we found that a complete feasible control gain region may be bounded, unbounded, empty or a union of several bounded and unbounded regions, with a similar shape to the synchronized region. An interesting possibility emerged that a network could be synchronized by both negative and positive feedback control simultaneously. By bridging synchronizability and synchronizing response speeds with a settling time index, we have developed timed synchronized region (TSR) as a substitute for the classical synchronized region to study finite time synchronization. As for the last condition, a graphical method was developed to estimate control gain with the minimum synchronization time (CGMST). Each condition has examples provided for illustration and verification.

New type of chaos synchronization in discrete-time systems: the F-M synchronization

NASA Astrophysics Data System (ADS)

Ouannas, Adel; Grassi, Giuseppe; Karouma, Abdulrahman; Ziar, Toufik; Wang, Xiong; Pham, Viet-Thanh

2018-04-01

In this paper, a new type of synchronization for chaotic (hyperchaotic) maps with different dimensions is proposed. The novel scheme is called F - M synchronization, since it combines the inverse generalized synchronization (based on a functional relationship F) with the matrix projective synchronization (based on a matrix M). In particular, the proposed approach enables F - M synchronization with index d to be achieved between n-dimensional drive system map and m-dimensional response system map, where the synchronization index d corresponds to the dimension of the synchronization error. The technique, which exploits nonlinear controllers and Lyapunov stability theory, proves to be effective in achieving the F - M synchronization not only when the synchronization index d equals n or m, but even if the synchronization index d is larger than the map dimensions n and m. Finally, simulation results are reported, with the aim to illustrate the capabilities of the novel scheme proposed herein.

Beta burst dynamics in Parkinson's disease OFF and ON dopaminergic medication.

PubMed

Tinkhauser, Gerd; Pogosyan, Alek; Tan, Huiling; Herz, Damian M; Kühn, Andrea A; Brown, Peter

2017-11-01

Exaggerated basal ganglia beta activity (13-35 Hz) is commonly found in patients with Parkinson's disease and can be suppressed by dopaminergic medication, with the degree of suppression being correlated with the improvement in motor symptoms. Importantly, beta activity is not continuously elevated, but fluctuates to give beta bursts. The percentage number of longer beta bursts in a given interval is positively correlated with clinical impairment in Parkinson's disease patients. Here we determine whether the characteristics of beta bursts are dependent on dopaminergic state. Local field potentials were recorded from the subthalamic nucleus of eight Parkinson's disease patients during temporary lead externalization during surgery for deep brain stimulation. The recordings took place with the patient quietly seated following overnight withdrawal of levodopa and after administration of levodopa. Beta bursts were defined by applying a common amplitude threshold and burst characteristics were compared between the two drug conditions. The amplitude of beta bursts, indicative of the degree of local neural synchronization, progressively increased with burst duration. Treatment with levodopa limited this evolution leading to a relative increase of shorter, lower amplitude bursts. Synchronization, however, was not limited to local neural populations during bursts, but also, when such bursts were cotemporaneous across the hemispheres, was evidenced by bilateral phase synchronization. The probability of beta bursts and the proportion of cotemporaneous bursts were reduced by levodopa. The percentage number of longer beta bursts in a given interval was positively related to motor impairment, while the opposite was true for the percentage number of short duration beta bursts. Importantly, the decrease in burst duration was also correlated with the motor improvement. In conclusion, we demonstrate that long duration beta bursts are associated with an increase in local and interhemispheric synchronization. This may compromise information coding capacity and thereby motor processing. Dopaminergic activity limits this uncontrolled beta synchronization by terminating long duration beta bursts, with positive consequences on network state and motor symptoms. © The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain.

Synchronous and metachronous neoplasms in gastric cancer patients: A 23-year study

PubMed Central

Ławniczak, Małgorzata; Gawin, Alicja; Jaroszewicz-Heigelmann, Halina; Rogoza-Mateja, Wiesława; Raszeja-Wyszomirska, Joanna; Białek, Andrzej; Karpińska-Kaczmarczyk, Katarzyna; Starzyńska, Teresa

2014-01-01

AIM: To determine the prevalence and characteristics of additional primary malignancies in gastric cancer (GC) patients. METHODS: GC patients (862 total; 570 men, 292 women; mean age 59.8 ± 12.8 years) diagnosed at the Department of Gastroenterology at Pomeranian Medical University over a period of 23 years were included in this retrospective analysis of a prospectively maintained database. Mean follow-up time was 31.3 ± 38.6 mo (range 1-241 mo). The following clinicopathological features of patients with synchronous tumors were compared to those with metachronous tumors: age, sex, symptom duration, family history of cancer, tumor site, stage (early vs advanced), histology, and blood group. GC patients with and without a second tumor were compared in terms of the same clinicopathological features. RESULTS: Of 862 GC patients, 58 (6.7%) developed a total of 62 multiple primary tumors, of which 39 (63%) were metachronous and 23 (37%) synchronous. Four (6.9%) of the 58 multiple GC patients developed two or more neoplasms. The predominant tumor type of the secondary neoplasms was colorectal (n = 17), followed by lung (n = 9), breast (n = 8), and prostate (n = 7). Age was the only clinicopathological feature that differed between GC patients with synchronous vs metachronous malignancies; GC patients with synchronous neoplasms were older than those with metachronous neoplasms (68.0 ± 10.3 years vs 59.9 ± 11.1 years, respectively, P = 0.008). Comparisons between patients with and without a second primary cancer revealed that the only statistically significant differences were in age and blood group. The mean age of the patients with multiple GC was higher than that of those without a second primary tumor (63.4 ± 11.4 years vs 59.5 ± 13.0 years, respectively, P = 0.026). GC patients with a second primary tumor were more commonly blood group O than those without (56.2% vs 31.6%, respectively, P = 0.002). CONCLUSION: GC patients may develop other primary cancers; appropriate preoperative and postoperative diagnostic modalities are thus required, particularly if patients are older and blood group O. PMID:24966619

Cumulative Reports and Publications through December 31, 1991 (Institute for Computer Applications in Science and Engineering)

DTIC Science & Technology

1992-02-01

universities and industry who have resident appointments for limited periods of time , and by consultants. Members of NASA’s research staff also may be...Submitted to Journal of Computational Physics. Banks, H. T., G. Propst, and R. J. Silcox: A comparison of time domain boundary conditions for acoustic...2, pp. 117-145, i991. Nicol, David M.: T/ cost of conservative synchronization in parallel discrete event sim- ulations. ICASE Report No. 90-20, May

ATS-6 - Synchronous orbit trapped radiation studies with an electron-proton spectrometer

NASA Technical Reports Server (NTRS)

Walker, R. J.; Swanson, R. L.; Winckler, J. R.; Erickson, K. N.

1975-01-01

The paper discusses the University of Minnesota experiment on ATS-6 designed to study the origin and dynamics of high-energy electrons and protons in the outer radiation belt and in the near-earth plasma sheet. The experiment consists of two nearly identical detector assemblies, each of which is a magnetic spectrometer containing four gold-silicon surface barrier detectors. The instrument provides a clean separation between protons and electrons by the combination of pulse height analysis and magnetic deflection.

Fault-tolerant clock synchronization in distributed systems

NASA Technical Reports Server (NTRS)

Ramanathan, Parameswaran; Shin, Kang G.; Butler, Ricky W.

1990-01-01

Existing fault-tolerant clock synchronization algorithms are compared and contrasted. These include the following: software synchronization algorithms, such as convergence-averaging, convergence-nonaveraging, and consistency algorithms, as well as probabilistic synchronization; hardware synchronization algorithms; and hybrid synchronization. The worst-case clock skews guaranteed by representative algorithms are compared, along with other important aspects such as time, message, and cost overhead imposed by the algorithms. More recent developments such as hardware-assisted software synchronization and algorithms for synchronizing large, partially connected distributed systems are especially emphasized.

Energy-absorption capability and scalability of square cross section composite tube specimens

NASA Technical Reports Server (NTRS)

Farley, Gary L.

1987-01-01

Static crushing tests were conducted on graphite/epoxy and Kevlar/epoxy square cross section tubes to study the influence of specimen geometry on the energy-absorption capability and scalability of composite materials. The tube inside width-to-wall thickness (W/t) ratio was determined to significantly affect the energy-absorption capability of composite materials. As W/t ratio decreases, the energy-absorption capability increases nonlinearly. The energy-absorption capability of Kevlar epoxy tubes was found to be geometrically scalable, but the energy-absorption capability of graphite/epoxy tubes was not geometrically scalable.

Composite synchronization of three eccentric rotors driven by induction motors in a vibrating system

NASA Astrophysics Data System (ADS)

Kong, Xiangxi; Chen, Changzheng; Wen, Bangchun

2018-03-01

This paper addresses the problem of composite synchronization of three eccentric rotors (ERs) driven by induction motors in a vibrating system. The composite synchronous motion of three ERs is composed of the controlled synchronous motion of two ERs and the self-synchronous motion of the third ER. Combining an adaptive sliding mode control (ASMC) algorithm with a modified master-slave control structure, the controllers are designed to implement controlled synchronous motion of two ERs with zero phase difference. Based on Lyapunov stability theorem and Barbalat's lemma, the stability of the designed controllers is verified. On basis of controlled synchronization of two ERs, self-synchronization of the third ER is introduced to implement composite synchronous motion of three ERs. The feasibility of the proposed composite synchronization method is analyzed by numerical method. The effects of motor and structure parameters on composite synchronous motion are discussed. Experiments on a vibrating test bench driven by three ERs are operated to validate the effectiveness of the proposed composite synchronization method, including a comparison with self-synchronization method.

A proportional integral estimator-based clock synchronization protocol for wireless sensor networks.

PubMed

Yang, Wenlun; Fu, Minyue

2017-11-01

Clock synchronization is an issue of vital importance in applications of WSNs. This paper proposes a proportional integral estimator-based protocol (EBP) to achieve clock synchronization for wireless sensor networks. As each local clock skew gradually drifts, synchronization accuracy will decline over time. Compared with existing consensus-based approaches, the proposed synchronization protocol improves synchronization accuracy under time-varying clock skews. Moreover, by restricting synchronization error of clock skew into a relative small quantity, it could reduce periodic re-synchronization frequencies. At last, a pseudo-synchronous implementation for skew compensation is introduced as synchronous protocol is unrealistic in practice. Numerical simulations are shown to illustrate the performance of the proposed protocol. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

MOEMs-based new functionalities for future instrumentation in space

NASA Astrophysics Data System (ADS)

Zamkotsian, Frédéric; Liotard, Arnaud; Viard, Thierry; Costes, Vincent; Hébert, Philippe-Jean; Hinglais, Emmanuel; Villenave, Michel

2017-11-01

Micro-Opto-Electro-Mechanical Systems (MOEMS) could be key components in future generation of space instruments. In Earth Observation, Universe Observation and Planet Exploration, scientific return of the instruments must be optimized in future missions. MOEMS devices are based on the mature micro-electronics technology and in addition to their compactness, scalability, and specific task customization, they could generate new functions not available with current technologies. CNES has initiated a study with LAM and TAS for listing the new functions associated with several types of MEMS (programmable slits, programmable micro-diffraction gratings, micro-deformable mirrors). Instrumental applications are then derived and promising concepts are described.

FY09 Final Report for LDRD Project: Understanding Viral Quasispecies Evolution through Computation and Experiment

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

Zhou, C

2009-11-12

In FY09 they will (1) complete the implementation, verification, calibration, and sensitivity and scalability analysis of the in-cell virus replication model; (2) complete the design of the cell culture (cell-to-cell infection) model; (3) continue the research, design, and development of their bioinformatics tools: the Web-based structure-alignment-based sequence variability tool and the functional annotation of the genome database; (4) collaborate with the University of California at San Francisco on areas of common interest; and (5) submit journal articles that describe the in-cell model with simulations and the bioinformatics approaches to evaluation of genome variability and fitness.

Programmable wide field spectrograph for earth observation

NASA Astrophysics Data System (ADS)

Zamkotsian, Frédéric; Lanzoni, Patrick; Liotard, Arnaud; Viard, Thierry; Costes, Vincent; Hébert, Philippe-Jean

2017-11-01

In Earth Observation, Universe Observation and Planet Exploration, scientific return of the instruments must be optimized in future missions. Micro-Opto-Electro-Mechanical Systems (MOEMS) could be key components in future generation of space instruments. These devices are based on the mature micro-electronics technology and in addition to their compactness, scalability, and specific task customization, they could generate new functions not available with current technologies. French and European space agencies, the Centre National d'Etudes Spatiales (CNES) and the European Space Agency (ESA) have initiated several studies with LAM and TAS for listing the new functions associated with several types of MEMS, and developing new ideas of instruments.

PRIMA-X Final Report

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

Lorenz, Daniel; Wolf, Felix

2016-02-17

The PRIMA-X (Performance Retargeting of Instrumentation, Measurement, and Analysis Technologies for Exascale Computing) project is the successor of the DOE PRIMA (Performance Refactoring of Instrumentation, Measurement, and Analysis Technologies for Petascale Computing) project, which addressed the challenge of creating a core measurement infrastructure that would serve as a common platform for both integrating leading parallel performance systems (notably TAU and Scalasca) and developing next-generation scalable performance tools. The PRIMA-X project shifts the focus away from refactorization of robust performance tools towards a re-targeting of the parallel performance measurement and analysis architecture for extreme scales. The massive concurrency, asynchronous execution dynamics,more » hardware heterogeneity, and multi-objective prerequisites (performance, power, resilience) that identify exascale systems introduce fundamental constraints on the ability to carry forward existing performance methodologies. In particular, there must be a deemphasis of per-thread observation techniques to significantly reduce the otherwise unsustainable flood of redundant performance data. Instead, it will be necessary to assimilate multi-level resource observations into macroscopic performance views, from which resilient performance metrics can be attributed to the computational features of the application. This requires a scalable framework for node-level and system-wide monitoring and runtime analyses of dynamic performance information. Also, the interest in optimizing parallelism parameters with respect to performance and energy drives the integration of tool capabilities in the exascale environment further. Initially, PRIMA-X was a collaborative project between the University of Oregon (lead institution) and the German Research School for Simulation Sciences (GRS). Because Prof. Wolf, the PI at GRS, accepted a position as full professor at Technische Universität Darmstadt (TU Darmstadt) starting February 1st, 2015, the project ended at GRS on January 31st, 2015. This report reflects the work accomplished at GRS until then. The work of GRS is expected to be continued at TU Darmstadt. The first main accomplishment of GRS is the design of different thread-level aggregation techniques. We created a prototype capable of aggregating the thread-level information in performance profiles using these techniques. The next step will be the integration of the most promising techniques into the Score-P measurement system and their evaluation. The second main accomplishment is a substantial increase of Score-P’s scalability, achieved by improving the design of the system-tree representation in Score-P’s profile format. We developed a new representation and a distributed algorithm to create the scalable system tree representation. Finally, we developed a lightweight approach to MPI wait-state profiling. Former algorithms either needed piggy-backing, which can cause significant runtime overhead, or tracing, which comes with its own set of scaling challenges. Our approach works with local data only and, thus, is scalable and has very little overhead.« less

ML Frame Synchronization for OFDM Systems Using a Known Pilot and Cyclic Prefixes

NASA Astrophysics Data System (ADS)

Huh, Heon

Orthogonal frequency-division multiplexing (OFDM) is a popular air interface technology that is adopted as a standard modulation scheme for 4G communication systems owing to its excellent spectral efficiency. For OFDM systems, synchronization problems have received much attention along with peak-to-average power ratio (PAPR) reduction. In addition to frequency offset estimation, frame synchronization is a challenging problem that must be solved to achieve optimal system performance. In this paper, we present a maximum likelihood (ML) frame synchronizer for OFDM systems. The synchronizer exploits a synchronization word and cyclic prefixes together to improve the synchronization performance. Numerical results show that the performance of the proposed frame synchronizer is better than that of conventional schemes. The proposed synchronizer can be used as a reference for evaluating the performance of other suboptimal frame synchronizers. We also modify the proposed frame synchronizer to reduce the implementation complexity and propose a near-ML synchronizer for time-varying fading channels.

Quantum synchronization in an optomechanical system based on Lyapunov control.

PubMed

Li, Wenlin; Li, Chong; Song, Heshan

2016-06-01

We extend the concepts of quantum complete synchronization and phase synchronization, which were proposed in A. Mari et al., Phys. Rev. Lett. 111, 103605 (2013)PRLTAO0031-900710.1103/PhysRevLett.111.103605, to more widespread quantum generalized synchronization. Generalized synchronization can be considered a necessary condition or a more flexible derivative of complete synchronization, and its criterion and synchronization measure are proposed and analyzed in this paper. As examples, we consider two typical generalized synchronizations in a designed optomechanical system. Unlike the effort to construct a special coupling synchronization system, we purposefully design extra control fields based on Lyapunov control theory. We find that the Lyapunov function can adapt to more flexible control objectives, which is more suitable for generalized synchronization control, and the control fields can be achieved simply with a time-variant voltage. Finally, the existence of quantum entanglement in different generalized synchronizations is also discussed.

Overview of Cell Synchronization.

PubMed

Banfalvi, Gaspar

2017-01-01

The widespread interest in cell synchronization is maintained by the studies of control mechanism involved in cell cycle regulation. During the synchronization distinct subpopulations of cells are obtained representing different stages of the cell cycle. These subpopulations are then used to study regulatory mechanisms of the cycle at the level of macromolecular biosynthesis (DNA synthesis, gene expression, protein synthesis), protein phosphorylation, development of new drugs, etc. Although several synchronization methods have been described, it is of general interest that scientists get a compilation and an updated view of these synchronization techniques. This introductory chapter summarizes: (1) the basic concepts and principal criteria of cell cycle synchronizations, (2) the most frequently used synchronization methods, such as physical fractionation (flow cytometry, dielectrophoresis, cytofluorometric purification), chemical blockade, (3) synchronization of embryonic cells, (4) synchronization at low temperature, (5) comparison of cell synchrony techniques, (6) synchronization of unicellular organisms, and (7) the effect of synchronization on transfection.

Disparity : scalable anomaly detection for clusters.

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

Desai, N.; Bradshaw, R.; Lusk, E.

2008-01-01

In this paper, we describe disparity, a tool that does parallel, scalable anomaly detection for clusters. Disparity uses basic statistical methods and scalable reduction operations to perform data reduction on client nodes and uses these results to locate node anomalies. We discuss the implementation of disparity and present results of its use on a SiCortex SC5832 system.

System and method to allow a synchronous motor to successfully synchronize with loads that have high inertia and/or high torque

DOEpatents

Melfi, Michael J.

2015-10-20

A mechanical soft-start type coupling is used as an interface between a line start, synchronous motor and a heavy load to enable the synchronous motor to bring the heavy load up to or near synchronous speed. The soft-start coupling effectively isolates the synchronous motor from the load for enough time to enable the synchronous motor to come up to full speed. The soft-start coupling then brings the load up to or near synchronous speed.

Scalable software-defined optical networking with high-performance routing and wavelength assignment algorithms.

PubMed

Lee, Chankyun; Cao, Xiaoyuan; Yoshikane, Noboru; Tsuritani, Takehiro; Rhee, June-Koo Kevin

2015-10-19

The feasibility of software-defined optical networking (SDON) for a practical application critically depends on scalability of centralized control performance. The paper, highly scalable routing and wavelength assignment (RWA) algorithms are investigated on an OpenFlow-based SDON testbed for proof-of-concept demonstration. Efficient RWA algorithms are proposed to achieve high performance in achieving network capacity with reduced computation cost, which is a significant attribute in a scalable centralized-control SDON. The proposed heuristic RWA algorithms differ in the orders of request processes and in the procedures of routing table updates. Combined in a shortest-path-based routing algorithm, a hottest-request-first processing policy that considers demand intensity and end-to-end distance information offers both the highest throughput of networks and acceptable computation scalability. We further investigate trade-off relationship between network throughput and computation complexity in routing table update procedure by a simulation study.

Guaranteeing synchronous message deadlines with the timed token medium access control protocol

NASA Technical Reports Server (NTRS)

Agrawal, Gopal; Chen, Baio; Zhao, Wei; Davari, Sadegh

1992-01-01

We study the problem of guaranteeing synchronous message deadlines in token ring networks where the timed token medium access control protocol is employed. Synchronous capacity, defined as the maximum time for which a node can transmit its synchronous messages every time it receives the token, is a key parameter in the control of synchronous message transmission. To ensure the transmission of synchronous messages before their deadlines, synchronous capacities must be properly allocated to individual nodes. We address the issue of appropriate allocation of the synchronous capacities. Several synchronous capacity allocation schemes are analyzed in terms of their ability to satisfy deadline constraints of synchronous messages. We show that an inappropriate allocation of the synchronous capacities could cause message deadlines to be missed even if the synchronous traffic is extremely low. We propose a scheme called the normalized proportional allocation scheme which can guarantee the synchronous message deadlines for synchronous traffic of up to 33 percent of available utilization. To date, no other synchronous capacity allocation scheme has been reported to achieve such substantial performance. Another major contribution of this paper is an extension to the previous work on the bounded token rotation time. We prove that the time elapsed between any consecutive visits to a particular node is bounded by upsilon TTRT, where TTRT is the target token rotation time set up at system initialization time. The previous result by Johnson and Sevcik is a special case where upsilon = 2. We use this result in the analysis of various synchronous allocation schemes. It can also be applied in other similar studies.

Synchronization of metronomes

NASA Astrophysics Data System (ADS)

Pantaleone, James

2002-10-01

Synchronization is a common phenomenon in physical and biological systems. We examine the synchronization of two (and more) metronomes placed on a freely moving base. The small motion of the base couples the pendulums causing synchronization. The synchronization is generally in-phase, with antiphase synchronization occurring only under special conditions. The metronome system provides a mechanical realization of the popular Kuramoto model for synchronization of biological oscillators, and is excellent for classroom demonstrations and an undergraduate physics lab.

Covalent Bonding of Thermoplastics to Rubbers for Printable, Reel-to-Reel Processing in Soft Robotics and Microfluidics.

PubMed

Taylor, Jay M; Perez-Toralla, Karla; Aispuro, Ruby; Morin, Stephen A

2018-02-01

The lamination of mechanically stiff structures to elastic materials is prevalent in biological systems and popular in many emerging synthetic systems, such as soft robotics, microfluidics, stretchable electronics, and pop-up assemblies. The disparate mechanical and chemical properties of these materials have made it challenging to develop universal synthetic procedures capable of reliably adhering to these classes of materials together. Herein, a simple and scalable procedure is described that is capable of covalently laminating a variety of commodity ("off-the-shelf") thermoplastic sheets to silicone rubber films. When combined with laser printing, the nonbonding sites can be "printed" onto the thermoplastic sheets, enabling the direct fabrication of microfluidic systems for actuation and liquid handling applications. The versatility of this approach in generating thin, multifunctional laminates is demonstrated through the fabrication of milliscale soft actuators and grippers with hinged articulation and microfluidic channels with built-in optical filtering and pressure-dependent geometries. This method of fabrication offers several advantages, including technical simplicity, process scalability, design versatility, and material diversity. The concepts and strategies presented herein are broadly applicable to the soft robotics, microfluidics, and advanced and additive manufacturing communities where hybrid rubber/plastic structures are prevalent. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fan-out Estimation in Spin-based Quantum Computer Scale-up.

PubMed

Nguyen, Thien; Hill, Charles D; Hollenberg, Lloyd C L; James, Matthew R

2017-10-17

Solid-state spin-based qubits offer good prospects for scaling based on their long coherence times and nexus to large-scale electronic scale-up technologies. However, high-threshold quantum error correction requires a two-dimensional qubit array operating in parallel, posing significant challenges in fabrication and control. While architectures incorporating distributed quantum control meet this challenge head-on, most designs rely on individual control and readout of all qubits with high gate densities. We analysed the fan-out routing overhead of a dedicated control line architecture, basing the analysis on a generalised solid-state spin qubit platform parameterised to encompass Coulomb confined (e.g. donor based spin qubits) or electrostatically confined (e.g. quantum dot based spin qubits) implementations. The spatial scalability under this model is estimated using standard electronic routing methods and present-day fabrication constraints. Based on reasonable assumptions for qubit control and readout we estimate 10 2 -10 5 physical qubits, depending on the quantum interconnect implementation, can be integrated and fanned-out independently. Assuming relatively long control-free interconnects the scalability can be extended. Ultimately, the universal quantum computation may necessitate a much higher number of integrated qubits, indicating that higher dimensional electronics fabrication and/or multiplexed distributed control and readout schemes may be the preferredstrategy for large-scale implementation.

Modeling Temporal Behavior in Large Networks: A Dynamic Mixed-Membership Model

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

Rossi, R; Gallagher, B; Neville, J

Given a large time-evolving network, how can we model and characterize the temporal behaviors of individual nodes (and network states)? How can we model the behavioral transition patterns of nodes? We propose a temporal behavior model that captures the 'roles' of nodes in the graph and how they evolve over time. The proposed dynamic behavioral mixed-membership model (DBMM) is scalable, fully automatic (no user-defined parameters), non-parametric/data-driven (no specific functional form or parameterization), interpretable (identifies explainable patterns), and flexible (applicable to dynamic and streaming networks). Moreover, the interpretable behavioral roles are generalizable, computationally efficient, and natively supports attributes. We applied ourmore » model for (a) identifying patterns and trends of nodes and network states based on the temporal behavior, (b) predicting future structural changes, and (c) detecting unusual temporal behavior transitions. We use eight large real-world datasets from different time-evolving settings (dynamic and streaming). In particular, we model the evolving mixed-memberships and the corresponding behavioral transitions of Twitter, Facebook, IP-Traces, Email (University), Internet AS, Enron, Reality, and IMDB. The experiments demonstrate the scalability, flexibility, and effectiveness of our model for identifying interesting patterns, detecting unusual structural transitions, and predicting the future structural changes of the network and individual nodes.« less

Scalable clustering algorithms for continuous environmental flow cytometry.

PubMed

Hyrkas, Jeremy; Clayton, Sophie; Ribalet, Francois; Halperin, Daniel; Armbrust, E Virginia; Howe, Bill

2016-02-01

Recent technological innovations in flow cytometry now allow oceanographers to collect high-frequency flow cytometry data from particles in aquatic environments on a scale far surpassing conventional flow cytometers. The SeaFlow cytometer continuously profiles microbial phytoplankton populations across thousands of kilometers of the surface ocean. The data streams produced by instruments such as SeaFlow challenge the traditional sample-by-sample approach in cytometric analysis and highlight the need for scalable clustering algorithms to extract population information from these large-scale, high-frequency flow cytometers. We explore how available algorithms commonly used for medical applications perform at classification of such a large-scale, environmental flow cytometry data. We apply large-scale Gaussian mixture models to massive datasets using Hadoop. This approach outperforms current state-of-the-art cytometry classification algorithms in accuracy and can be coupled with manual or automatic partitioning of data into homogeneous sections for further classification gains. We propose the Gaussian mixture model with partitioning approach for classification of large-scale, high-frequency flow cytometry data. Source code available for download at https://github.com/jhyrkas/seaflow_cluster, implemented in Java for use with Hadoop. hyrkas@cs.washington.edu Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Scalable streaming tools for analyzing N-body simulations: Finding halos and investigating excursion sets in one pass

NASA Astrophysics Data System (ADS)

Ivkin, N.; Liu, Z.; Yang, L. F.; Kumar, S. S.; Lemson, G.; Neyrinck, M.; Szalay, A. S.; Braverman, V.; Budavari, T.

2018-04-01

Cosmological N-body simulations play a vital role in studying models for the evolution of the Universe. To compare to observations and make a scientific inference, statistic analysis on large simulation datasets, e.g., finding halos, obtaining multi-point correlation functions, is crucial. However, traditional in-memory methods for these tasks do not scale to the datasets that are forbiddingly large in modern simulations. Our prior paper (Liu et al., 2015) proposes memory-efficient streaming algorithms that can find the largest halos in a simulation with up to 109 particles on a small server or desktop. However, this approach fails when directly scaling to larger datasets. This paper presents a robust streaming tool that leverages state-of-the-art techniques on GPU boosting, sampling, and parallel I/O, to significantly improve performance and scalability. Our rigorous analysis of the sketch parameters improves the previous results from finding the centers of the 103 largest halos (Liu et al., 2015) to ∼ 104 - 105, and reveals the trade-offs between memory, running time and number of halos. Our experiments show that our tool can scale to datasets with up to ∼ 1012 particles while using less than an hour of running time on a single GPU Nvidia GTX 1080.

Development of Modeling Methods and Tools for Predicting Coupled Reactive Transport Processes in Porous Media at Multiple Scales

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

Clement, T. Prabhakar; Barnett, Mark O.; Zheng, Chunmiao

DE-FG02-06ER64213: Development of Modeling Methods and Tools for Predicting Coupled Reactive Transport Processes in Porous Media at Multiple Scales Investigators: T. Prabhakar Clement (PD/PI) and Mark O. Barnett (Auburn), Chunmiao Zheng (Univ. of Alabama), and Norman L. Jones (BYU). The objective of this project was to develop scalable modeling approaches for predicting the reactive transport of metal contaminants. We studied two contaminants, a radioactive cation [U(VI)] and a metal(loid) oxyanion system [As(III/V)], and investigated their interactions with two types of subsurface materials, iron and manganese oxyhydroxides. We also developed modeling methods for describing the experimental results. Overall, the project supportedmore » 25 researchers at three universities. Produced 15 journal articles, 3 book chapters, 6 PhD dissertations and 6 MS theses. Three key journal articles are: 1) Jeppu et al., A scalable surface complexation modeling framework for predicting arsenate adsorption on goethite-coated sands, Environ. Eng. Sci., 27(2): 147-158, 2010. 2) Loganathan et al., Scaling of adsorption reactions: U(VI) experiments and modeling, Applied Geochemistry, 24 (11), 2051-2060, 2009. 3) Phillippi, et al., Theoretical solid/solution ratio effects on adsorption and transport: uranium (VI) and carbonate, Soil Sci. Soci. of America, 71:329-335, 2007« less

On Synchronization Primitive Systems.

DTIC Science & Technology

The report studies the question: what synchronization primitive should be used to handle inter-process communication. A formal model is presented...between these synchronization primitives. Although only four synchronization primitives are compared, the general methods can be used to compare other... synchronization primitives. Moreover, in the definitions of these synchronization primitives, conditional branches are explicitly allowed. In addition

Mass synchronization: Occurrence and its control with possible applications to brain dynamics

NASA Astrophysics Data System (ADS)

Chandrasekar, V. K.; Sheeba, Jane H.; Lakshmanan, M.

2010-12-01

Occurrence of strong or mass synchronization of a large number of neuronal populations in the brain characterizes its pathological states. In order to establish an understanding of the mechanism underlying such pathological synchronization, we present a model of coupled populations of phase oscillators representing the interacting neuronal populations. Through numerical analysis, we discuss the occurrence of mass synchronization in the model, where a source population which gets strongly synchronized drives the target populations onto mass synchronization. We hypothesize and identify a possible cause for the occurrence of such a synchronization, which is so far unknown: Pathological synchronization is caused not just because of the increase in the strength of coupling between the populations but also because of the strength of the strong synchronization of the drive population. We propose a demand controlled method to control this pathological synchronization by providing a delayed feedback where the strength and frequency of the synchronization determine the strength and the time delay of the feedback. We provide an analytical explanation for the occurrence of pathological synchronization and its control in the thermodynamic limit.

Architecture Knowledge for Evaluating Scalable Databases

DTIC Science & Technology

2015-01-16

problems, arising from the proliferation of new data models and distributed technologies for building scalable, available data stores . Architects must...longer are relational databases the de facto standard for building data repositories. Highly distributed, scalable “ NoSQL ” databases [11] have emerged...This is especially challenging at the data storage layer. The multitude of competing NoSQL database technologies creates a complex and rapidly

Scalable and Manageable Storage Systems

DTIC Science & Technology

2000-12-01

Despite our long- distance relationship, my brothers and sisters, Charfeddine, Amel, Ghazi, Hajer, Nabeel , and Ines overwhelmed me with more love and...that enable storage sys - tems to be more cost-effectively scalable. Furthermore, the dissertation proposes an approach to ensure automatic load...and addresses three key technical challenges to making storage sys - tems more cost-effectively scalable and manageable. 1.2 Dissertation research The

A scalable infrastructure for CMS data analysis based on OpenStack Cloud and Gluster file system

NASA Astrophysics Data System (ADS)

Toor, S.; Osmani, L.; Eerola, P.; Kraemer, O.; Lindén, T.; Tarkoma, S.; White, J.

2014-06-01

The challenge of providing a resilient and scalable computational and data management solution for massive scale research environments requires continuous exploration of new technologies and techniques. In this project the aim has been to design a scalable and resilient infrastructure for CERN HEP data analysis. The infrastructure is based on OpenStack components for structuring a private Cloud with the Gluster File System. We integrate the state-of-the-art Cloud technologies with the traditional Grid middleware infrastructure. Our test results show that the adopted approach provides a scalable and resilient solution for managing resources without compromising on performance and high availability.

Adaptive UEP and Packet Size Assignment for Scalable Video Transmission over Burst-Error Channels

NASA Astrophysics Data System (ADS)

Lee, Chen-Wei; Yang, Chu-Sing; Su, Yih-Ching

2006-12-01

This work proposes an adaptive unequal error protection (UEP) and packet size assignment scheme for scalable video transmission over a burst-error channel. An analytic model is developed to evaluate the impact of channel bit error rate on the quality of streaming scalable video. A video transmission scheme, which combines the adaptive assignment of packet size with unequal error protection to increase the end-to-end video quality, is proposed. Several distinct scalable video transmission schemes over burst-error channel have been compared, and the simulation results reveal that the proposed transmission schemes can react to varying channel conditions with less and smoother quality degradation.

Scalability enhancement of AODV using local link repairing

NASA Astrophysics Data System (ADS)

Jain, Jyoti; Gupta, Roopam; Bandhopadhyay, T. K.

2014-09-01

Dynamic change in the topology of an ad hoc network makes it difficult to design an efficient routing protocol. Scalability of an ad hoc network is also one of the important criteria of research in this field. Most of the research works in ad hoc network focus on routing and medium access protocols and produce simulation results for limited-size networks. Ad hoc on-demand distance vector (AODV) is one of the best reactive routing protocols. In this article, modified routing protocols based on local link repairing of AODV are proposed. Method of finding alternate routes for next-to-next node is proposed in case of link failure. These protocols are beacon-less, means periodic hello message is removed from the basic AODV to improve scalability. Few control packet formats have been changed to accommodate suggested modification. Proposed protocols are simulated to investigate scalability performance and compared with basic AODV protocol. This also proves that local link repairing of proposed protocol improves scalability of the network. From simulation results, it is clear that scalability performance of routing protocol is improved because of link repairing method. We have tested protocols for different terrain area with approximate constant node densities and different traffic load.

Wanted: Scalable Tracers for Diffusion Measurements

PubMed Central

2015-01-01

Scalable tracers are potentially a useful tool to examine diffusion mechanisms and to predict diffusion coefficients, particularly for hindered diffusion in complex, heterogeneous, or crowded systems. Scalable tracers are defined as a series of tracers varying in size but with the same shape, structure, surface chemistry, deformability, and diffusion mechanism. Both chemical homology and constant dynamics are required. In particular, branching must not vary with size, and there must be no transition between ordinary diffusion and reptation. Measurements using scalable tracers yield the mean diffusion coefficient as a function of size alone; measurements using nonscalable tracers yield the variation due to differences in the other properties. Candidate scalable tracers are discussed for two-dimensional (2D) diffusion in membranes and three-dimensional diffusion in aqueous solutions. Correlations to predict the mean diffusion coefficient of globular biomolecules from molecular mass are reviewed briefly. Specific suggestions for the 3D case include the use of synthetic dendrimers or random hyperbranched polymers instead of dextran and the use of core–shell quantum dots. Another useful tool would be a series of scalable tracers varying in deformability alone, prepared by varying the density of crosslinking in a polymer to make say “reinforced Ficoll” or “reinforced hyperbranched polyglycerol.” PMID:25319586

Bifurcation behaviors of synchronized regions in logistic map networks with coupling delay

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

Tang, Longkun, E-mail: tomlk@hqu.edu.cn, E-mail: xqwu@whu.edu.cn; Wu, Xiaoqun, E-mail: tomlk@hqu.edu.cn, E-mail: xqwu@whu.edu.cn; Lu, Jun-an, E-mail: jalu@whu.edu.cn

2015-03-15

Network synchronized regions play an extremely important role in network synchronization according to the master stability function framework. This paper focuses on network synchronous state stability via studying the effects of nodal dynamics, coupling delay, and coupling way on synchronized regions in Logistic map networks. Theoretical and numerical investigations show that (1) network synchronization is closely associated with its nodal dynamics. Particularly, the synchronized region bifurcation points through which the synchronized region switches from one type to another are in good agreement with those of the uncoupled node system, and chaotic nodal dynamics can greatly impede network synchronization. (2) Themore » coupling delay generally impairs the synchronizability of Logistic map networks, which is also dominated by the parity of delay for some nodal parameters. (3) A simple nonlinear coupling facilitates network synchronization more than the linear one does. The results found in this paper will help to intensify our understanding for the synchronous state stability in discrete-time networks with coupling delay.« less

Synchronous motor with soft start element formed between the motor rotor and motor output shaft to successfully synchronize loads that have high inertia and/or high torque

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

Umans, Stephen D; Nisley, Donald L; Melfi, Michael J

A line-start synchronous motor has a housing, a rotor shaft, and an output shaft. A soft-start coupling portion is operatively coupled to the output shaft and the rotor shaft. The soft-start coupling portion is configurable to enable the synchronous motor to obtain synchronous operation and to drive, at least near synchronous speed during normal steady state operation of the motor, a load having characteristics sufficient to prevent obtaining normal synchronous operation of the motor when the motor is operatively connected to the load in the absence of the soft-start coupling. The synchronous motor is sufficiently rated to obtain synchronous operationmore » and to drive, at least near synchronous speed during normal steady state operation of the motor, a load having characteristics sufficient to prevent obtaining normal synchronous operation of the motor when the motor is operatively connected to the load in the absence of the soft-start coupling.« less

Collective synchronization of divisions in Drosophila development

NASA Astrophysics Data System (ADS)

Vergassola, Massimo

Mitoses in the early development of most metazoans are rapid and synchronized across the entire embryo. While diffusion is too slow, in vitro experiments have shown that waves of the cell-cycle regulator Cdk1 can transfer information rapidly across hundreds of microns. However, the signaling dynamics and the physical properties of chemical waves during embryonic development remain unclear. We develop FRET biosensors for the activity of Cdk1 and the checkpoint kinase Chk1 in Drosophila embryos and exploit them to measure waves in vivo. We demonstrate that Cdk1 chemical waves control mitotic waves and that their speed is regulated by the activity of Cdk1 during the S-phase (and not mitosis). We quantify the progressive slowdown of the waves with developmental cycles and identify its underlying control mechanism by the DNA replication checkpoint through the Chk1/Wee1 pathway. The global dynamics of the mitotic signaling network illustrates a novel control principle: the S-phase activity of Cdk1 regulates the speed of the mitotic wave, while the Cdk1 positive feedback ensures an invariantly rapid onset of mitosis. Mathematical modeling captures the speed of the waves and predicts a fundamental distinction between the S-phase Cdk1 trigger waves and the mitotic phase waves, which is illustrated by embryonic ablation experiments. In collaboration with Victoria Deneke1, Anna Melbinger2, and Stefano Di Talia1 1 Department of Cell Biology, Duke University Medical Center 2 Department of Physics, University of California San Diego.

Growth synchrony between leaves and stems during twig development differs among plant functional types of subtropical rainforest woody species.

PubMed

Meng, Fengqun; Zhang, Guangfu; Li, Xincheng; Niklas, Karl J; Sun, Shucun

2015-06-01

During the development of woody twigs, the growth in leaf may or may not be proportional to the growth in stem. The presence or absence of a synchronicity between these two phenologies may reflect differences in life history adaptive strategies concerning carbon gain. We hypothesized that sun-adapted species are more likely to be less synchronous between growths in total leaf area (TLA) and stem length compared with shade-adapted species, with a bias in growth in stem length, and that shade-adapted species are more likely to be more synchronous between increases in individual leaf area (ILA) (leaf size) and leaf number (LN) during twig development compared with sun-adapted species, giving priority to growth of leaf size. We tested these two hypotheses by recording the phenologies of leaf emergence, leaf expansion and stem elongation during twig development for 19 evergreen woody species (including five shade-adapted understory species, six sun-adapted understory species and eight sun-adapted canopy species) in a subtropical evergreen broad-leaved forest in eastern China. We constructed indices to characterize the synchronicity between TLA and stem length (αLS) and between leaf size and leaf number (αSN) and we derived the α values from logistic functions taking the general form of A = A(max)/[1 + exp(β - αB)] (where A is the TLA or average ILA, B is the corresponding stem length or LN at a specific time, and A(max) is the maximum TLA or the maximum ILA of a twig; the higher the numerical value of α, the less synchronous the corresponding phenologies). Consistent with our hypotheses, sun-adapted species were higher both in α(LS) and α(SN), showing less synchronous patterns in the growths of TLA vs stem length and leaf size vs LN during twig development. Moreover, α(LS) and α(SN) were significantly positively correlated with relative growth rates of LN and leaf size across species, as indicated by both analyses of ordinary regression and phylogenetic generalized least squares. The across-species synchronies during twig development show that the temporal dynamics of the leaf size-twig size spectrum is of adaptive significance in plants. We suggest that temporal dynamics of plant functional traits should be extensively studied to characterize plant life history. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Emergence of synchronization induced by the interplay between two prisoner's dilemma games with volunteering in small-world networks

NASA Astrophysics Data System (ADS)

Chen, Yong; Qin, Shao-Meng; Yu, Lianchun; Zhang, Shengli

2008-03-01

We studied synchronization between prisoner’s dilemma games with voluntary participation in two Newman-Watts small-world networks. It was found that there are three kinds of synchronization: partial phase synchronization, total phase synchronization, and complete synchronization, for varied coupling factors. Besides, two games can reach complete synchronization for the large enough coupling factor. We also discussed the effect of the coupling factor on the amplitude of oscillation of cooperator density.

Stages of chaotic synchronization.

PubMed

Tang, D. Y.; Dykstra, R.; Hamilton, M. W.; Heckenberg, N. R.

1998-09-01

In an experimental investigation of the response of a chaotic system to a chaotic driving force, we have observed synchronization of chaos of the response system in the forms of generalized synchronization, phase synchronization, and lag synchronization to the driving signal. In this paper we compare the features of these forms of synchronized chaos and study their relations and physical origins. We found that different forms of chaotic synchronization could be interpreted as different stages of nonlinear interaction between the coupled chaotic systems. (c) 1998 American Institute of Physics.

Three-tier multi-granularity switching system based on PCE

NASA Astrophysics Data System (ADS)

Wang, Yubao; Sun, Hao; Liu, Yanfei

2017-10-01

With the growing demand for business communications, electrical signal processing optical path switching can't meet the demand. The multi-granularity switch system that can improve node routing and switching capabilities came into being. In the traditional network, each node is responsible for calculating the path; synchronize the whole network state, which will increase the burden on the network, so the concept of path calculation element (PCE) is proposed. The PCE is responsible for routing and allocating resources in the network1. In the traditional band-switched optical network, the wavelength is used as the basic routing unit, resulting in relatively low wavelength utilization. Due to the limitation of wavelength continuity, the routing design of the band technology becomes complicated, which directly affects the utilization of the system. In this paper, optical code granularity is adopted. There is no continuity of the optical code, and the number of optical codes is more flexible than the wavelength. For the introduction of optical code switching, we propose a Code Group Routing Entity (CGRE) algorithm. In short, the combination of three-tier multi-granularity optical switching system and PCE can simplify the network structure, reduce the node load, and enhance the network scalability and survivability. Realize the intelligentization of optical network.

Engineering the evolution of self-organizing behaviors in swarm robotics: a case study.

PubMed

Trianni, Vito; Nolfi, Stefano

2011-01-01

Evolutionary robotics (ER) is a powerful approach for the automatic synthesis of robot controllers, as it requires little a priori knowledge about the problem to be solved in order to obtain good solutions. This is particularly true for collective and swarm robotics, in which the desired behavior of the group is an indirect result of the control and communication rules followed by each individual. However, the experimenter must make several arbitrary choices in setting up the evolutionary process, in order to define the correct selective pressures that can lead to the desired results. In some cases, only a deep understanding of the obtained results can point to the critical aspects that constrain the system, which can be later modified in order to re-engineer the evolutionary process towards better solutions. In this article, we discuss the problem of engineering the evolutionary machinery that can lead to the desired result in the swarm robotics context. We also present a case study about self-organizing synchronization in a swarm of robots, in which some arbitrarily chosen properties of the communication system hinder the scalability of the behavior to large groups. We show that by modifying the communication system, artificial evolution can synthesize behaviors that scale properly with the group size.

3D bioprinted functional and contractile cardiac tissue constructs

PubMed Central

Wang, Zhan; Lee, Sang Jin; Cheng, Heng-Jie; Yoo, James J.; Atala, Anthony

2018-01-01

Bioengineering of a functional cardiac tissue composed of primary cardiomyocytes has great potential for myocardial regeneration and in vitro tissue modeling. However, its applications remain limited because the cardiac tissue is a highly organized structure with unique physiologic, biomechanical, and electrical properties. In this study, we undertook a proof-of-concept study to develop a contractile cardiac tissue with cellular organization, uniformity, and scalability by using three-dimensional (3D) bioprinting strategy. Primary cardiomyocytes were isolated from infant rat hearts and suspended in a fibrin-based bioink to determine the priting capability for cardiac tissue engineering. This cell-laden hydrogel was sequentially printed with a sacrificial hydrogel and a supporting polymeric frame through a 300-μm nozzle by pressured air. Bioprinted cardiac tissue constructs had a spontaneous synchronous contraction in culture, implying in vitro cardiac tissue development and maturation. Progressive cardiac tissue development was confirmed by immunostaining for α-actinin and connexin 43, indicating that cardiac tissues were formed with uniformly aligned, dense, and electromechanically coupled cardiac cells. These constructs exhibited physiologic responses to known cardiac drugs regarding beating frequency and contraction forces. In addition, Notch signaling blockade significantly accelerated development and maturation of bioprinted cardiac tissues. Our results demonstrated the feasibility of bioprinting functional cardiac tissues that could be used for tissue engineering applications and pharmaceutical purposes. PMID:29452273

Rocinante, a virtual collaborative visualizer

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

McDonald, M.J.; Ice, L.G.

1996-12-31

With the goal of improving the ability of people around the world to share the development and use of intelligent systems, Sandia National Laboratories` Intelligent Systems and Robotics Center is developing new Virtual Collaborative Engineering (VCE) and Virtual Collaborative Control (VCC) technologies. A key area of VCE and VCC research is in shared visualization of virtual environments. This paper describes a Virtual Collaborative Visualizer (VCV), named Rocinante, that Sandia developed for VCE and VCC applications. Rocinante allows multiple participants to simultaneously view dynamic geometrically-defined environments. Each viewer can exclude extraneous detail or include additional information in the scene as desired.more » Shared information can be saved and later replayed in a stand-alone mode. Rocinante automatically scales visualization requirements with computer system capabilities. Models with 30,000 polygons and 4 Megabytes of texture display at 12 to 15 frames per second (fps) on an SGI Onyx and at 3 to 8 fps (without texture) on Indigo 2 Extreme computers. In its networked mode, Rocinante synchronizes its local geometric model with remote simulators and sensory systems by monitoring data transmitted through UDP packets. Rocinante`s scalability and performance make it an ideal VCC tool. Users throughout the country can monitor robot motions and the thinking behind their motion planners and simulators.« less

Leveraging master-slave OpenFlow controller arrangement to improve control plane resiliency in SD-EONs.

PubMed

Chen, Xiaoliang; Zhao, Bin; Ma, Shoujiang; Chen, Cen; Hu, Daoyun; Zhou, Wenshuang; Zhu, Zuqing

2015-03-23

In this paper, we study how to improve the control plane resiliency of software-defined elastic optical networks (SD-EONs) and design a master-slave OpenFlow (OF) controller arrangement. Specifically, we introduce two OF controllers (OF-Cs), i.e., the master and slave OF-Cs, and make them work in a collaborative way to protect the SD-EON against controller failures. We develop a controller communication protocol (CCP) to facilitate the cooperation of the two OF-Cs. With the CCP, the master OF-C (M-OF-C) can synchronize network status to the slave OF-C (S-OF-C) in real time, while S-OF-C can quickly detect the failure of M-OF-C and take over the network control and management (NC&M) tasks timely to avoid service disruption. We implement the proposed framework in an SD-EON control plane testbed built with high-performance servers, and perform NC&M experiments with different network failure scenarios to demonstrate its effectiveness. Experimental results indicate that the proposed system can restore services in both the data and control planes of SD-EON jointly while maintaining relatively good scalability. To the best of our knowledge, this is the first demonstration that realizes control plane resiliency in SD-EONs.

Design of the Protocol Processor for the ROBUS-2 Communication System

NASA Technical Reports Server (NTRS)

Torres-Pomales, Wilfredo; Malekpour, Mahyar R.; Miner, Paul S.

2005-01-01

The ROBUS-2 Protocol Processor (RPP) is a custom-designed hardware component implementing the functionality of the ROBUS-2 fault-tolerant communication system. The Reliable Optical Bus (ROBUS) is the core communication system of the Scalable Processor-Independent Design for Enhanced Reliability (SPIDER), a general-purpose fault tolerant integrated modular architecture currently under development at NASA Langley Research Center. ROBUS is a time-division multiple access (TDMA) broadcast communication system with medium access control by means of time-indexed communication schedule. ROBUS-2 is a developmental version of the ROBUS providing guaranteed fault-tolerant services to the attached processing elements (PEs), in the presence of a bounded number of faults. These services include message broadcast (Byzantine Agreement), dynamic communication schedule update, time reference (clock synchronization), and distributed diagnosis (group membership). ROBUS also features fault-tolerant startup and restart capabilities. ROBUS-2 tolerates internal as well as PE faults, and incorporates a dynamic self-reconfiguration capability driven by the internal diagnostic system. ROBUS consists of RPPs connected to each other by a lower-level physical communication network. The RPP has a pipelined architecture and the design is parameterized in the behavioral and structural domains. The design of the RPP enables the bus to achieve a PE-message throughput that approaches the available bandwidth at the physical layer.

The Population Tracking Model: A Simple, Scalable Statistical Model for Neural Population Data

PubMed Central

O'Donnell, Cian; alves, J. Tiago Gonç; Whiteley, Nick; Portera-Cailliau, Carlos; Sejnowski, Terrence J.

2017-01-01

Our understanding of neural population coding has been limited by a lack of analysis methods to characterize spiking data from large populations. The biggest challenge comes from the fact that the number of possible network activity patterns scales exponentially with the number of neurons recorded (∼2Neurons). Here we introduce a new statistical method for characterizing neural population activity that requires semi-independent fitting of only as many parameters as the square of the number of neurons, requiring drastically smaller data sets and minimal computation time. The model works by matching the population rate (the number of neurons synchronously active) and the probability that each individual neuron fires given the population rate. We found that this model can accurately fit synthetic data from up to 1000 neurons. We also found that the model could rapidly decode visual stimuli from neural population data from macaque primary visual cortex about 65 ms after stimulus onset. Finally, we used the model to estimate the entropy of neural population activity in developing mouse somatosensory cortex and, surprisingly, found that it first increases, and then decreases during development. This statistical model opens new options for interrogating neural population data and can bolster the use of modern large-scale in vivo Ca2+ and voltage imaging tools. PMID:27870612

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

Perumalla, Kalyan S.; Yoginath, Srikanth B.

Problems such as fault tolerance and scalable synchronization can be efficiently solved using reversibility of applications. Making applications reversible by relying on computation rather than on memory is ideal for large scale parallel computing, especially for the next generation of supercomputers in which memory is expensive in terms of latency, energy, and price. In this direction, a case study is presented here in reversing a computational core, namely, Basic Linear Algebra Subprograms, which is widely used in scientific applications. A new Reversible BLAS (RBLAS) library interface has been designed, and a prototype has been implemented with two modes: (1) amore » memory-mode in which reversibility is obtained by checkpointing to memory in forward and restoring from memory in reverse, and (2) a computational-mode in which nothing is saved in the forward, but restoration is done entirely via inverse computation in reverse. The article is focused on detailed performance benchmarking to evaluate the runtime dynamics and performance effects, comparing reversible computation with checkpointing on both traditional CPU platforms and recent GPU accelerator platforms. For BLAS Level-1 subprograms, data indicates over an order of magnitude better speed of reversible computation compared to checkpointing. For BLAS Level-2 and Level-3, a more complex tradeoff is observed between reversible computation and checkpointing, depending on computational and memory complexities of the subprograms.« less

The synchronicity between the stock and the stock index via information in market

NASA Astrophysics Data System (ADS)

Gao, Hai-Ling; Li, Jiang-Cheng; Guo, Wei; Mei, Dong-Cheng

2018-02-01

The synchronicity between the stock and the stock-index in a market system is investigated. The results show that: (i) the synchronicity between the stock and the stock-index increases with the rising degree of market information capitalized into stock prices in certain range; (ii) the synchronicity decreases for large firm-specific information; (iii) the stock return synchronicity is small compared to the big noise trading, however the variance noise facilitates the synchronization within the tailored realms. These findings may be helpful in understanding the effect of market information on synchronicity, especially for the response of firm-specific information and noise trading to synchronicity.

Conceptual Architecture for Obtaining Cyber Situational Awareness

DTIC Science & Technology

2014-06-01

1-893723-17-8. [10] SKYBOX SECURITY. Developer´s Guide. Skybox View. Manual.Version 11. 2010. [11] SCALABLE Network. EXata communications...E. Understanding command and control. Washington, D.C.: CCRP Publication Series, 2006. 255 p. ISBN 1-893723-17-8. • [10] SKYBOX SECURITY. Developer...s Guide. Skybox View. Manual.Version 11. 2010. • [11] SCALABLE Network. EXata communications simulation platform. Available: <http://www.scalable

Scalable Power-Component Models for Concept Testing

DTIC Science & Technology

2011-08-17

Scalable Power-Component Models for Concept Testing, Mazzola, et al . UNCLASSIFIED: Dist A. Approved for public release 2011 NDIA GROUND VEHICLE...Power-Component Models for Concept Testing, Mazzola, et al . UNCLASSIFIED: Dist A. Approved for public release Page 2 of 8 technology that has yet...Technology Symposium (GVSETS) Scalable Power-Component Models for Concept Testing, Mazzola, et al . UNCLASSIFIED: Dist A. Approved for public release

TriG: Next Generation Scalable Spaceborne GNSS Receiver

NASA Technical Reports Server (NTRS)

Tien, Jeffrey Y.; Okihiro, Brian Bachman; Esterhuizen, Stephan X.; Franklin, Garth W.; Meehan, Thomas K.; Munson, Timothy N.; Robison, David E.; Turbiner, Dmitry; Young, Lawrence E.

2012-01-01

TriG is the next generation NASA scalable space GNSS Science Receiver. It will track all GNSS and additional signals (i.e. GPS, GLONASS, Galileo, Compass and Doris). Scalable 3U architecture and fully software and firmware recofigurable, enabling optimization to meet specific mission requirements. TriG GNSS EM is currently undergoing testing and is expected to complete full performance testing later this year.

Synchronization of distributed power grids with the external loading system

NASA Astrophysics Data System (ADS)

Wei, Duqu; Mei, Chuncao

2018-06-01

In this paper, the synchronization between spatially distributed power plants and their supported consumers is studied, where the case of Kuramoto-like model power grids connected to an external permanent magnet synchronous motor (PMSM) is taken as an example. We focus on the dependence of the synchronization on the coupling coefficient. To quantitatively study the synchronization degree, we introduce the order parameter and the frequency deviation to measure the synchronization of the coupled system. It is found that as the external coupling coefficient is increased, the distributed power grids and the loading system become more and more synchronized in space, and the complete synchronization appears at a particular value of external coupling coefficient. Our results may provide a useful tip for analyzing the synchronous ability of distributed power grids.

Capturing with EEG the neural entrainment and coupling underlying sensorimotor synchronization to the beat.

PubMed

Nozaradan, Sylvie; Zerouali, Younes; Peretz, Isabelle; Mouraux, André

2015-03-01

Synchronizing movements with rhythmic inputs requires tight coupling of sensory and motor neural processes. Here, using a novel approach based on the recording of steady-state-evoked potentials (SS-EPs), we examine how distant brain areas supporting these processes coordinate their dynamics. The electroencephalogram was recorded while subjects listened to a 2.4-Hz auditory beat and tapped their hand on every second beat. When subjects tapped to the beat, the EEG was characterized by a 2.4-Hz SS-EP compatible with beat-related entrainment and a 1.2-Hz SS-EP compatible with movement-related entrainment, based on the results of source analysis. Most importantly, when compared with passive listening of the beat, we found evidence suggesting an interaction between sensory- and motor-related activities when subjects tapped to the beat, in the form of (1) additional SS-EP appearing at 3.6 Hz, compatible with a nonlinear product of sensorimotor integration; (2) phase coupling of beat- and movement-related activities; and (3) selective enhancement of beat-related activities over the hemisphere contralateral to the tapping, suggesting a top-down effect of movement-related activities on auditory beat processing. Taken together, our results are compatible with the view that rhythmic sensorimotor synchronization is supported by a dynamic coupling of sensory and motor related activities. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Neuronal avalanches and coherence potentials

NASA Astrophysics Data System (ADS)

Plenz, D.

2012-05-01

The mammalian cortex consists of a vast network of weakly interacting excitable cells called neurons. Neurons must synchronize their activities in order to trigger activity in neighboring neurons. Moreover, interactions must be carefully regulated to remain weak (but not too weak) such that cascades of active neuronal groups avoid explosive growth yet allow for activity propagation over long-distances. Such a balance is robustly realized for neuronal avalanches, which are defined as cortical activity cascades that follow precise power laws. In experiments, scale-invariant neuronal avalanche dynamics have been observed during spontaneous cortical activity in isolated preparations in vitro as well as in the ongoing cortical activity of awake animals and in humans. Theory, models, and experiments suggest that neuronal avalanches are the signature of brain function near criticality at which the cortex optimally responds to inputs and maximizes its information capacity. Importantly, avalanche dynamics allow for the emergence of a subset of avalanches, the coherence potentials. They emerge when the synchronization of a local neuronal group exceeds a local threshold, at which the system spawns replicas of the local group activity at distant network sites. The functional importance of coherence potentials will be discussed in the context of propagating structures, such as gliders in balanced cellular automata. Gliders constitute local population dynamics that replicate in space after a finite number of generations and are thought to provide cellular automata with universal computation. Avalanches and coherence potentials are proposed to constitute a modern framework of cortical synchronization dynamics that underlies brain function.

Papillary serous carcinoma of the uterus: increased risk of subsequent or concurrent development of breast carcinoma.

PubMed

Geisler, J P; Sorosky, J I; Duong, H L; Buekers, T E; Geisler, M J; Sood, A K; Anderson, B; Buller, R E

2001-12-01

Some women with endometrial cancer may be at increased risk for developing breast cancer. The histologic type of endometrial cancer associated with synchronous or subsequent breast cancer has not been clearly established. Our purpose was to determine if a certain histologic type of endometrial cancer was associated with an increased risk of synchronous or subsequent breast cancer. The University of Iowa Hospitals and Clinics tumor registry was queried to ascertain all patients with the diagnosis of uterine cancer from January 1, 1983, to December 31, 1994. Statistics were performed utilizing SPSS for Windows version 9.0 (SPSS Inc., Chicago, IL), including Student's t tests and chi(2) tests. Five hundred ninety-two patients had endometrial adenocarcinoma during the study period. Five hundred thirty-six women had endometrioid adenocarcinoma, 23 women had papillary serous carcinoma (UPSC), 21 women had adenosquamous carcinoma, 10 women had clear-cell carcinoma, and 1 woman each had mucinous or squamous carcinoma. Twelve patients had previously been diagnosed with breast carcinomas. Twenty-five patients were diagnosed with breast cancer either concurrently or subsequent to their diagnosis of endometrial cancer. Synchronous or subsequent breast cancers developed in 3.2% of patients with endometrioid carcinoma and in 25% of patients with UPSC (P < 0.001). Patients with UPSC have an increased risk of development of breast cancer as compared to patients with endometrioid adenocarcinoma of the uterus. (c)2001 Elsevier Science.

Synchronization of spontaneous otoacoustic emissions in the tokay gecko

NASA Astrophysics Data System (ADS)

Roongthumskul, Yuttana; Hudspeth, A. J.

2018-05-01

Spontaneous otoacoustic emissions (SOAEs) are a universal feature of all classes of tetrapods. Although the generation mechanism of SOAEs are incompletely understood, these emissions are undoubtedly associated with the active process of the inner ear. In most lizards, unlike mammals and amphibians, robust SOAEs can ordinarily be detected from both ears. In this work, we investigated the interactions between emissions recorded simultaneously from the two ears of tokay geckos. We found that the frequency spectra of SOAEs from both ears of an individual animal are partially correlated: the peaks of several emissions occur at identical frequencies. To investigate the underlying mechanisms of these identical-frequency SOAEs, we perturbed the emissions from one or both ears by manipulating the pressure in the ear canals or by decreasing the local temperature in the vicinity of one inner ear. Suppression of SOAEs due to large positive pressures revealed that some identical-frequency emissions were generated unilaterally, whereas others were contributed by both ears at identical or slightly different frequencies. These bilaterally generated SOAEs became desynchronized as their frequency detuning grew sufficiently large, a phenomenon consistent with the synchronization of two active oscillators. Finally, we found that manipulations of the volume of the oral cavity or altering the impedance of the tympanum strongly affected the synchronization of SOAEs. These findings agreed with previous studies suggesting that the tokay gecko, like other lizards, exhibits strong acoustic coupling between its tympani through the oral cavity.

Cortical Gray and Adjacent White Matter Demonstrate Synchronous Maturation in Very Preterm Infants.

PubMed

Smyser, Tara A; Smyser, Christopher D; Rogers, Cynthia E; Gillespie, Sarah K; Inder, Terrie E; Neil, Jeffrey J

2016-08-01

Spatial and functional gradients of development have been described for the maturation of cerebral gray and white matter using histological and radiological approaches. We evaluated these patterns in very preterm (VPT) infants using diffusion tensor imaging. Data were obtained from 3 groups: 1) 22 VPT infants without white matter injury (WMI), of whom all had serial MRI studies during the neonatal period, 2) 19 VPT infants with WMI, of whom 3 had serial MRI studies and 3) 12 healthy, term-born infants. Regions of interest were placed in the cortical gray and adjacent white matter in primary motor, primary visual, visual association, and prefrontal regions. From the MRI data at term-equivalent postmenstrual age, differences in mean diffusivity were found in all areas between VPT infants with WMI and the other 2 groups. In contrast, minimal differences in fractional anisotropy were found between the 3 groups. These findings suggest that cortical maturation is delayed in VPT infants with WMI when compared with term control infants and VPT infants without WMI. From the serial MRI data from VPT infants, synchronous development between gray and white matter was evident in all areas and all groups, with maturation in primary motor and sensory regions preceding that of association areas. This finding highlights the regionally varying but locally synchronous nature of the development of cortical gray matter and its adjacent white matter. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Temporal coherence for pure tones in budgerigars (Melopsittacus undulatus) and humans (Homo sapiens).

PubMed

Neilans, Erikson G; Dent, Micheal L

2015-02-01

Auditory scene analysis has been suggested as a universal process that exists across all animals. Relative to humans, however, little work has been devoted to how animals perceptually isolate different sound sources. Frequency separation of sounds is arguably the most common parameter studied in auditory streaming, but it is not the only factor contributing to how the auditory scene is perceived. Researchers have found that in humans, even at large frequency separations, synchronous tones are heard as a single auditory stream, whereas asynchronous tones with the same frequency separations are perceived as 2 distinct sounds. These findings demonstrate how both the timing and frequency separation of sounds are important for auditory scene analysis. It is unclear how animals, such as budgerigars (Melopsittacus undulatus), perceive synchronous and asynchronous sounds. In this study, budgerigars and humans (Homo sapiens) were tested on their perception of synchronous, asynchronous, and partially overlapping pure tones using the same psychophysical procedures. Species differences were found between budgerigars and humans in how partially overlapping sounds were perceived, with budgerigars more likely to segregate overlapping sounds and humans more apt to fuse the 2 sounds together. The results also illustrated that temporal cues are particularly important for stream segregation of overlapping sounds. Lastly, budgerigars were found to segregate partially overlapping sounds in a manner predicted by computational models of streaming, whereas humans were not. PsycINFO Database Record (c) 2015 APA, all rights reserved.

Neuronal synchrony: Peculiarity and generality

PubMed Central

Nowotny, Thomas; Huerta, Ramon; Rabinovich, Mikhail I.

2008-01-01

Synchronization in neuronal systems is a new and intriguing application of dynamical systems theory. Why are neuronal systems different as a subject for synchronization? (1) Neurons in themselves are multidimensional nonlinear systems that are able to exhibit a wide variety of different activity patterns. Their “dynamical repertoire” includes regular or chaotic spiking, regular or chaotic bursting, multistability, and complex transient regimes. (2) Usually, neuronal oscillations are the result of the cooperative activity of many synaptically connected neurons (a neuronal circuit). Thus, it is necessary to consider synchronization between different neuronal circuits as well. (3) The synapses that implement the coupling between neurons are also dynamical elements and their intrinsic dynamics influences the process of synchronization or entrainment significantly. In this review we will focus on four new problems: (i) the synchronization in minimal neuronal networks with plastic synapses (synchronization with activity dependent coupling), (ii) synchronization of bursts that are generated by a group of nonsymmetrically coupled inhibitory neurons (heteroclinic synchronization), (iii) the coordination of activities of two coupled neuronal networks (partial synchronization of small composite structures), and (iv) coarse grained synchronization in larger systems (synchronization on a mesoscopic scale). PMID:19045493

Synchronization Analysis of Master-Slave Probabilistic Boolean Networks.

PubMed

Lu, Jianquan; Zhong, Jie; Li, Lulu; Ho, Daniel W C; Cao, Jinde

2015-08-28

In this paper, we analyze the synchronization problem of master-slave probabilistic Boolean networks (PBNs). The master Boolean network (BN) is a deterministic BN, while the slave BN is determined by a series of possible logical functions with certain probability at each discrete time point. In this paper, we firstly define the synchronization of master-slave PBNs with probability one, and then we investigate synchronization with probability one. By resorting to new approach called semi-tensor product (STP), the master-slave PBNs are expressed in equivalent algebraic forms. Based on the algebraic form, some necessary and sufficient criteria are derived to guarantee synchronization with probability one. Further, we study the synchronization of master-slave PBNs in probability. Synchronization in probability implies that for any initial states, the master BN can be synchronized by the slave BN with certain probability, while synchronization with probability one implies that master BN can be synchronized by the slave BN with probability one. Based on the equivalent algebraic form, some efficient conditions are derived to guarantee synchronization in probability. Finally, several numerical examples are presented to show the effectiveness of the main results.