Science.gov

Sample records for grid connected integrated

  1. Establishment of key grid-connected performance index system for integrated PV-ES system

    NASA Astrophysics Data System (ADS)

    Li, Q.; Yuan, X. D.; Qi, Q.; Liu, H. M.

    2016-08-01

    In order to further promote integrated optimization operation of distributed new energy/ energy storage/ active load, this paper studies the integrated photovoltaic-energy storage (PV-ES) system which is connected with the distribution network, and analyzes typical structure and configuration selection for integrated PV-ES generation system. By combining practical grid- connected characteristics requirements and technology standard specification of photovoltaic generation system, this paper takes full account of energy storage system, and then proposes several new grid-connected performance indexes such as paralleled current sharing characteristic, parallel response consistency, adjusting characteristic, virtual moment of inertia characteristic, on- grid/off-grid switch characteristic, and so on. A comprehensive and feasible grid-connected performance index system is then established to support grid-connected performance testing on integrated PV-ES system.

  2. Grid Connected Functionality

    DOE Data Explorer

    Baker, Kyri; Jin, Xin; Vaidynathan, Deepthi; Jones, Wesley; Christensen, Dane; Sparn, Bethany; Woods, Jason; Sorensen, Harry; Lunacek, Monte

    2016-08-04

    Dataset demonstrating the potential benefits that residential buildings can provide for frequency regulation services in the electric power grid. In a hardware-in-the-loop (HIL) implementation, simulated homes along with a physical laboratory home are coordinated via a grid aggregator, and it is shown that their aggregate response has the potential to follow the regulation signal on a timescale of seconds. Connected (communication-enabled), devices in the National Renewable Energy Laboratory's (NREL's) Energy Systems Integration Facility (ESIF) received demand response (DR) requests from a grid aggregator, and the devices responded accordingly to meet the signal while satisfying user comfort bounds and physical hardware limitations.

  3. Integrating renewable energy resources with energy storage for grid-connected systems

    NASA Astrophysics Data System (ADS)

    Carr, Joseph

    Renewable energy resources have been growing at a rapidly accelerating rate as an alternative for fossil fuels in the modern electric grid. As their penetration increases, variability in these resources, particularly wind and solar, poses a risk of instability on the grid. Energy storage can be used to mitigate this risk as well as provide other benefits to the larger grid. In this dissertation, a novel high frequency common bus multiport converter is proposed as a new integration scheme to improve efficiency of the power electronics interface by reducing the number of conversion steps and to reduce the system size by replacing the line frequency transformer with a high frequency transformer tied to the common bus. Two main innovations are introduced: a new switching scheme for the H-bridges on the common bus which allows them to operate in parallel without interfering in each others operation, and a novel single-phase to three-phase matrix converter which converts the high frequency bus to the line frequency in a single conversion stage. This proposed converter is simulated to develop the inner loop control methodology, then a low power prototype is constructed and tested to verify its operation. The results of these tests demonstrate the feasibility of the proposed ideas as well as suggesting new avenues of research to further improve the proposed system.

  4. Integration of plug-in hybrid electric vehicles (PHEV) with grid connected residential photovoltaic energy systems

    NASA Astrophysics Data System (ADS)

    Nagarajan, Adarsh; Shireen, Wajiha

    2013-06-01

    This paper proposes an approach for integrating Plug-In Hybrid Electric Vehicles (PHEV) to an existing residential photovoltaic system, to control and optimize the power consumption of residential load. Control involves determining the source from which residential load will be catered, where as optimization of power flow reduces the stress on the grid. The system built to achieve the goal is a combination of the existing residential photovoltaic system, PHEV, Power Conditioning Unit (PCU), and a controller. The PCU involves two DC-DC Boost Converters and an inverter. This paper emphasizes on developing the controller logic and its implementation in order to accommodate the flexibility and benefits of the proposed integrated system. The proposed controller logic has been simulated using MATLAB SIMULINK and further implemented using Digital Signal Processor (DSP) microcontroller, TMS320F28035, from Texas Instruments

  5. Discrete-Time Integral Sliding Mode Control with Disturbances Compensation and Reduced Chattering for Pv Grid-Connected Inverter

    NASA Astrophysics Data System (ADS)

    Meo, Santolo; Sorrentino, Vincenzo

    2015-03-01

    In the paper a new discrete-time integral sliding mode control (DISMC) with disturbances compensation and reduced chattering for grid-connected inverter is proposed for active and reactive power regulation. Differently by many SMC proposed in literature that have a time-continuous formulation in spite have been implemented with digital processor, the proposed DISMC is fully formulated in discrete-time, taking into account the effects introduced by a microprocessor-based implementation. As will be demonstrated such approach consents to reduce the chattering about the sliding manifold within a boundary layer of O(T2) thickness instead of O(T) (being T the sampling period of the control algorithm). Moreover it introduces a correction of the control vector which eliminates the influence of modeling error and external disturbances improving stability and robustness of the controlled system. Constant converter switching frequency is achieved by using space vector modulation, which eases the design of the ac harmonic filter. In the paper, after a detailed formalization of the proposed control algorithm, several numerical and experimental results on a three-phase grid-connected inverter prototype are shown, proving the effectiveness of the control strategy.

  6. Smart Grid Integration Laboratory

    SciTech Connect

    Troxell, Wade

    2011-12-22

    The initial federal funding for the Colorado State University Smart Grid Integration Laboratory is through a Congressionally Directed Project (CDP), DE-OE0000070 Smart Grid Integration Laboratory. The original program requested in three one-year increments for staff acquisition, curriculum development, and instrumentation all which will benefit the Laboratory. This report focuses on the initial phase of staff acquisition which was directed and administered by DOE NETL/ West Virginia under Project Officer Tom George. Using this CDP funding, we have developed the leadership and intellectual capacity for the SGIC. This was accomplished by investing (hiring) a core team of Smart Grid Systems engineering faculty focused on education, research, and innovation of a secure and smart grid infrastructure. The Smart Grid Integration Laboratory will be housed with the separately funded Integrid Laboratory as part of CSU's overall Smart Grid Integration Center (SGIC). The period of performance of this grant was 10/1/2009 to 9/30/2011 which included one no cost extension due to time delays in faculty hiring. The Smart Grid Integration Laboratory's focus is to build foundations to help graduate and undergraduates acquire systems engineering knowledge; conduct innovative research; and team externally with grid smart organizations. Using the results of the separately funded Smart Grid Workforce Education Workshop (May 2009) sponsored by the City of Fort Collins, Northern Colorado Clean Energy Cluster, Colorado State University Continuing Education, Spirae, and Siemens has been used to guide the hiring of faculty, program curriculum and education plan. This project develops faculty leaders with the intellectual capacity to inspire its students to become leaders that substantially contribute to the development and maintenance of Smart Grid infrastructure through topics such as: (1) Distributed energy systems modeling and control; (2) Energy and power conversion; (3) Simulation of

  7. On automating domain connectivity for overset grids

    NASA Technical Reports Server (NTRS)

    Chiu, Ing-Tsau

    1994-01-01

    An alternative method for domain connectivity among systems of overset grids is presented. Reference uniform Cartesian systems of points are used to achieve highly efficient domain connectivity, and form the basis for a future fully automated system. The Cartesian systems are used to approximated body surfaces and to map the computational space of component grids. By exploiting the characteristics of Cartesian Systems, Chimera type hole-cutting and identification of donor elements for intergrid boundary points can be carried out very efficiently. The method is tested for a range of geometrically complex multiple-body overset grid systems.

  8. On automating domain connectivity for overset grids

    NASA Technical Reports Server (NTRS)

    Chiu, Ing-Tsau; Meakin, Robert L.

    1995-01-01

    An alternative method for domain connectivity among systems of overset grids is presented. Reference uniform Cartesian systems of points are used to achieve highly efficient domain connectivity, and form the basis for a future fully automated system. The Cartesian systems are used to approximate body surfaces and to map the computational space of component grids. By exploiting the characteristics of Cartesian systems, Chimera type hole-cutting and identification of donor elements for intergrid boundary points can be carried out very efficiently. The method is tested for a range of geometrically complex multiple-body overset grid systems. A dynamic hole expansion/contraction algorithm is also implemented to obtain optimum domain connectivity; however, it is tested only for geometry of generic shapes.

  9. Grid-connected PV systems - How and where they fit

    NASA Astrophysics Data System (ADS)

    Thomas, M. G.; Jones, G. J.

    The use of grid-connected photovoltaic systems requires substantial improvements in system economics. By integrating anticipated improvements in economics with consumer needs and perceptions, the various potential applications have been order-ranked. Third-party ownership of large systems appears to have the largest potential, residential has a modest potential, and the intermediate dedicated-load application potential appears to be small.

  10. High-efficiency grid-connected photovoltaic module integrated converter system with high-speed communication interfaces for small-scale distribution power generation

    SciTech Connect

    Choi, Woo-Young; Lai, Jih-Sheng

    2010-04-15

    This paper presents a high-efficiency grid-connected photovoltaic (PV) module integrated converter (MIC) system with reduced PV current variation. The proposed PV MIC system consists of a high-efficiency step-up DC-DC converter and a single-phase full-bridge DC-AC inverter. An active-clamping flyback converter with a voltage-doubler rectifier is proposed for the step-up DC-DC converter. The proposed step-up DC-DC converter reduces the switching losses by eliminating the reverse-recovery current of the output rectifying diodes. To reduce the PV current variation introduced by the grid-connected inverter, a PV current variation reduction method is also suggested. The suggested PV current variation reduction method reduces the PV current variation without any additional components. Moreover, for centralized power control of distributed PV MIC systems, a PV power control scheme with both a central control level and a local control level is presented. The central PV power control level controls the whole power production by sending out reference power signals to each individual PV MIC system. The proposed step-up DC-DC converter achieves a high-efficiency of 97.5% at 260 W output power to generate the DC-link voltage of 350 V from the PV voltage of 36.1 V. The PV MIC system including the DC-DC converter and the DC-AC inverter achieves a high-efficiency of 95% with the PV current ripple less than 3% variation of the rated PV current. (author)

  11. Solar energy grid integration systems "SEGIS"

    SciTech Connect

    None, None

    2007-10-01

    The inevitable transformation of the electrical grid to a more distributed generation configuration requires solar system capabilities well beyond simple net-metered, grid-connected approaches. Time-of-use and peak-demand rate structures will require more sophisticated systems designs that integrate energy management and/or energy storage into the system architecture. Controlling power flow into and from the utility grid will be required to ensure grid reliability and power quality. Alternative protection strategies will also be required to accommodate large numbers of distributed energy sources. This document provides an overview of the R&D needs and describes some pathways to promising solutions. The solutions will, in many cases, require R&D of new components, innovative inverter/controllers, energy management systems, innovative energy storage and a suite of advanced control algorithms, technical methodologies, protocols and the associated communications. It is expected that these solutions will help to push the “advanced integrated system” and “smart grid” evolutionary processes forward in a faster but focused manner.

  12. The CMS integration grid testbed

    SciTech Connect

    Graham, Gregory E.

    2004-08-26

    The CMS Integration Grid Testbed (IGT) comprises USCMS Tier-1 and Tier-2 hardware at the following sites: the California Institute of Technology, Fermi National Accelerator Laboratory, the University of California at San Diego, and the University of Florida at Gainesville. The IGT runs jobs using the Globus Toolkit with a DAGMan and Condor-G front end. The virtual organization (VO) is managed using VO management scripts from the European Data Grid (EDG). Gridwide monitoring is accomplished using local tools such as Ganglia interfaced into the Globus Metadata Directory Service (MDS) and the agent based Mona Lisa. Domain specific software is packaged and installed using the Distribution After Release (DAR) tool of CMS, while middleware under the auspices of the Virtual Data Toolkit (VDT) is distributed using Pacman. During a continuous two month span in Fall of 2002, over 1 million official CMS GEANT based Monte Carlo events were generated and returned to CERN for analysis while being demonstrated at SC2002. In this paper, we describe the process that led to one of the world's first continuously available, functioning grids.

  13. Grid : A Graphical Object Connecting Language

    NASA Astrophysics Data System (ADS)

    Taylor, Ian; Schutz, Bernard

    1997-08-01

    Signal-processing systems are fast becoming an essential tool within the scientific community. This is primarily due to the need for constructing large complex algorithms which would take many hours of work to code using conventional programming languages. Grid/>Grid OCL (Object Connecting Language) is a graphical interactive multi-threaded environment allowing users to create complex algorithms by creating a flexible object-oriented block diagram of the analysis required. Algorithms can be run incrementally or continuously e.g. when analysing long data streams. Grid (1.0 alpha) is written in Java (about 37,000 lines of code) and is currently distributed free of charge over the WWW. Although originally developed to analyse data taken from the GEO 600 gravitational wave detector, its use has been much more widespread e.g. collaborators are working on tools for various signal and image problems, multimedia teaching aids and even to construct a musical composition system.

  14. Automatic partitioning of unstructured grids into connected components

    NASA Technical Reports Server (NTRS)

    Dagum, Leonardo

    1993-01-01

    This paper presents two partitioning schemes that guarantee connected components given a connected initial grid. Connected components are important for convergence of methods such as domain decomposition or multigrid. For many of the grids tested, the schemes produce partitions as good (in terms of number of cut edges) or better than spectral partitioning and require only modest computational resources. This paper describes the two schemes in detail and presents comparison results from a number of two and three dimensional unstructured grids.

  15. Grid Integration Studies: Data Requirements, Greening the Grid

    SciTech Connect

    Katz, Jessica

    2015-06-01

    A grid integration study is an analytical framework used to evaluate a power system with high penetration levels of variable renewable energy (VRE). A grid integration study simulates the operation of the power system under different VRE scenarios, identifying reliability constraints and evaluating the cost of actions to alleviate those constraints. These VRE scenarios establish where, how much, and over what timeframe to build generation and transmission capacity, ideally capturing the spatial diversity benefits of wind and solar resources. The results help build confidence among policymakers, system operators, and investors to move forward with plans to increase the amount of VRE on the grid.

  16. Development of a low-cost integrated 20-kW ac solar tracking sub- array for grid-connected PV power system applications. Phase 1, Annual technical report, 11 July 1995--31 July 1996

    SciTech Connect

    Stern, M.; West, R.; Fourer, G.; Whalen, W.; Van Loo, M.; Duran, G.

    1997-06-01

    The overall goal of this effort is to reduce the installed cost of utility scale grid connected photovoltaic power systems. The focus of the effort is on ``BOS`` (Balance-Of-System) component manufacturing technology, which essentially involves all PV power system engineering, manufacturing, assembly and construction tasks from the receipt of a PV module to the deliver of grid connected electricity.

  17. Task 4 completion report for 40 Kilowatt grid connected modification contract

    NASA Technical Reports Server (NTRS)

    Vogt, J. H.

    1983-01-01

    Startup, operation in grid connect mode, shutdown from grid connects, operation in isolated mode, shutdown from isolated mode, steady state operation, mode transfers, and voltage disconnects are addressed.

  18. High Penetration, Grid Connected Photovoltaic Technology Codes and Standards: Preprint

    SciTech Connect

    Basso, T. S.

    2008-05-01

    This paper reports the interim status in identifying and reviewing photovoltaic (PV) codes and standards (C&S) and related electrical activities for grid-connected, high-penetration PV systems with a focus on U.S. electric utility distribution grid interconnection.

  19. Scaling Up Renewable Energy Generation: Aligning Targets and Incentives with Grid Integration Considerations, Greening The Grid

    SciTech Connect

    Katz, Jessica; Cochran, Jaquelin

    2015-05-27

    Greening the Grid provides technical assistance to energy system planners, regulators, and grid operators to overcome challenges associated with integrating variable renewable energy into the grid. This document, part of a Greening the Grid toolkit, provides power system planners with tips to help secure and sustain investment in new renewable energy generation by aligning renewable energy policy targets and incentives with grid integration considerations.

  20. Domain connectivity among systems of overset grids

    NASA Technical Reports Server (NTRS)

    Meakin, Robert L.

    1993-01-01

    This progress report describes research performed to achieve algorithmic improvements in the use of overset grids for the computation of unsteady flowfields about geometrically complex and moving component configurations. A hole-map computational method is detailed that reduces computational demand and corresponding demand on human resources. Results indicate that the method is both efficient and flexible for use in complex simulation cases. Tests were performed on shuttle orbiter/external tank, wing/store, and V-22 tilt-rotor configurations. The number of simulated points and the corresponding time on a SGI 4D-210 workstation are presented.

  1. Correlations and Functional Connections in a Population of Grid Cells

    PubMed Central

    Roudi, Yasser

    2015-01-01

    We study the statistics of spike trains of simultaneously recorded grid cells in freely behaving rats. We evaluate pairwise correlations between these cells and, using a maximum entropy kinetic pairwise model (kinetic Ising model), study their functional connectivity. Even when we account for the covariations in firing rates due to overlapping fields, both the pairwise correlations and functional connections decay as a function of the shortest distance between the vertices of the spatial firing pattern of pairs of grid cells, i.e. their phase difference. They take positive values between cells with nearby phases and approach zero or negative values for larger phase differences. We find similar results also when, in addition to correlations due to overlapping fields, we account for correlations due to theta oscillations and head directional inputs. The inferred connections between neurons in the same module and those from different modules can be both negative and positive, with a mean close to zero, but with the strongest inferred connections found between cells of the same module. Taken together, our results suggest that grid cells in the same module do indeed form a local network of interconnected neurons with a functional connectivity that supports a role for attractor dynamics in the generation of grid pattern. PMID:25714908

  2. TeraGrid's integrated information service.

    SciTech Connect

    Liming, L.; Navarro, J.-P.; Blau, E.; Brechin, J.; Catlett, C.; Dahan, M.; Diehl, D.; Dooley, R.; Dwyer, M.; Ericson, K.; Foster, I.; Hanna, E.; Hart, D. L.; Jordan, C.; Light, R.; Martin, S.; McGee, J.; Pearlman, L.; Reilly, J.; Scavo, T.; Shapiro, M.; Smallen, S.; Smith, W.; Wilkins-Diehr, N.

    2009-01-01

    The NSF TeraGrid project has designed and constructed a federated integrated information service (IIS) to serve its capability publishing and discovery needs. This service has also proven helpful in automating TeraGrid's operational activities. We describe the requirements that motivated this work; IIS's system architecture, information architecture, and information content; processes that IIS currently supports; and how various layers of the system architecture are being used. We also review motivating use cases that have not yet been satisfied by IIS and outline approaches for future work.

  3. Role of Smarter Grids in Variable Renewable Resource Integration (Presentation)

    SciTech Connect

    Miller, M.

    2012-07-01

    This presentation discusses the role of smarter grids in variable renewable resource integration and references material from a forthcoming ISGAN issue paper: Smart Grid Contributions to Variable Renewable Resource Integration, co-written by the presenter and currently in review.

  4. Solar cells having integral collector grids

    NASA Technical Reports Server (NTRS)

    Evans, J. C., Jr. (Inventor)

    1978-01-01

    A heterojunction or Schottky barrier photovoltaic device is described, comprising a conductive base metal layer. A back surface field region was formed at the interface between the device and the base metal layer, a transparent, conductive mixed metal oxide layer in integral contact with the n-type layer of the heterojunction or Schottky barrier device. A metal alloy grid network was included. An insulating layer prevented electrical contact between the conductive metal base layer and the transparent, conductive metal oxide layer.

  5. 78 FR 12042 - Electric Grid Integration Technical Workshops

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-21

    ... not limited to) smart grid, energy storage, cyber security, advanced computation--and investigating... Electric Grid Integration Technical Workshops AGENCY: Grid Tech Team, U.S. Department of Energy. ACTION... developing a targeted research and development roadmap to address grid challenges that will help...

  6. Four Federal Grid-Connected Photovoltaic Systems: Powering Our Nation's Capital with Solar

    SciTech Connect

    Plympton, P.; Kappaz, P.; Kroposki, B.; Stafford, B.; Thornton, J.

    2001-04-16

    One of the fastest growing markets for photovoltaics (PV) is the urban sector. Municipal planners have discovered that PV systems operate favorably in their urban areas, and can be aesthetically integrated into the urban landscape. The federal government has a long history of using PV in a variety of applications, but until recently few applications have been in urban environments. During the last five years, four grid-connected PV systems have been installed on federally owned or federally leased facilities in the Washington, D.C. area: (1) Earth Day Park, (2) U.S. Department of Energy Headquarters, (3) the Pentagon, and (4) Federal Energy Regulatory Commission Headquarters. This paper reviews these four urban, grid-connected systems-particularly the issues of siting, permitting, and grid interconnection.

  7. Integrating Renewable Electricity on the Grid

    NASA Astrophysics Data System (ADS)

    Crabtree, George; Misewich, Jim; Ambrosio, Ron; Clay, Kathryn; DeMartini, Paul; James, Revis; Lauby, Mark; Mohta, Vivek; Moura, John; Sauer, Peter; Slakey, Francis; Lieberman, Jodi; Tai, Humayun

    2011-11-01

    patchwork of conventional transmission lines would create an interstate highway system for electricity that moves large amounts of renewable electric power efficiently over long distances from source to load. Research and development is needed to identify the technical challenges associated with DC superconducting transmission and how it can be most effectively deployed. The challenge of variability can be met (i) by switching conventional generation capacity in or out in response to sophisticated forecasts of weather and power generation, (ii) by large scale energy storage in heat, pumped hydroelectric, compressed air or stationary batteries designed for the grid, or (iii) by national balancing of regional generation deficits and excesses using long distance transmission. Each of these solutions to variability has merit and each requires significant research and development to understand its capacity, performance, cost and effectiveness. The challenge of variability is likely to be met by a combination of these three solutions; the interactions among them and the appropriate mix needs to be explored. The long distances from renewable sources to demand centers span many of the grid's physical, ownership and regulatory boundaries. This introduces a new feature to grid structure and operation: national and regional coordination. The grid is historically a patchwork of local generation resources and load centers that has been built, operated and regulated to meet local needs. Although it is capable of sharing power across moderate distances, the arrangements for doing so are cumbersome and inefficient. The advent of renewable electricity with its enormous potential and inherent regional and national character presents an opportunity to examine the local structure of the grid and establish coordinating principles that will not only enable effective renewable integration but also simplify and codify the grid's increasingly regional and national character.

  8. Integrated geometry and grid generation system for complex configurations

    NASA Technical Reports Server (NTRS)

    Akdag, Vedat; Wulf, Armin

    1992-01-01

    A grid generation system was developed that enables grid generation for complex configurations. The system called ICEM/CFD is described and its role in computational fluid dynamics (CFD) applications is presented. The capabilities of the system include full computer aided design (CAD), grid generation on the actual CAD geometry definition using robust surface projection algorithms, interfacing easily with known CAD packages through common file formats for geometry transfer, grid quality evaluation of the volume grid, coupling boundary condition set-up for block faces with grid topology generation, multi-block grid generation with or without point continuity and block to block interface requirement, and generating grid files directly compatible with known flow solvers. The interactive and integrated approach to the problem of computational grid generation not only substantially reduces manpower time but also increases the flexibility of later grid modifications and enhancements which is required in an environment where CFD is integrated into a product design cycle.

  9. Metrics for Assessment of Smart Grid Data Integrity Attacks

    SciTech Connect

    Annarita Giani; Miles McQueen; Russell Bent; Kameshwar Poolla; Mark Hinrichs

    2012-07-01

    There is an emerging consensus that the nation’s electricity grid is vulnerable to cyber attacks. This vulnerability arises from the increasing reliance on using remote measurements, transmitting them over legacy data networks to system operators who make critical decisions based on available data. Data integrity attacks are a class of cyber attacks that involve a compromise of information that is processed by the grid operator. This information can include meter readings of injected power at remote generators, power flows on transmission lines, and relay states. These data integrity attacks have consequences only when the system operator responds to compromised data by redispatching generation under normal or contingency protocols. These consequences include (a) financial losses from sub-optimal economic dispatch to service loads, (b) robustness/resiliency losses from placing the grid at operating points that are at greater risk from contingencies, and (c) systemic losses resulting from cascading failures induced by poor operational choices. This paper is focused on understanding the connections between grid operational procedures and cyber attacks. We first offer two examples to illustrate how data integrity attacks can cause economic and physical damage by misleading operators into taking inappropriate decisions. We then focus on unobservable data integrity attacks involving power meter data. These are coordinated attacks where the compromised data are consistent with the physics of power flow, and are therefore passed by any bad data detection algorithm. We develop metrics to assess the economic impact of these attacks under re-dispatch decisions using optimal power flow methods. These metrics can be use to prioritize the adoption of appropriate countermeasures including PMU placement, encryption, hardware upgrades, and advance attack detection algorithms.

  10. GRID integration of oceanographic remote instrumentation

    NASA Astrophysics Data System (ADS)

    Salon, S.; Bolzon, G.; Mauri, E.; Poulain, P.-M.

    2009-04-01

    The observations provided by oceanographic remote instruments are essential for the purposes of the operational oceanography, nowadays a constantly growing and powerful tool to monitor, analyze and predict the state of the marine resources as well as the sustainable development of coastal areas [1]. Near real time (NRT) observations at the sea surface and in the water column, e.g., temperature and salinity (T/S) profiles, are of central importance for the operational forecasting system in the Mediterranean Sea. The management of the network of floats deployed in the Mediterranean Sea and handled by the MedArgo Regional Argo Centre at OGS [2][3] is a complex task that may be greatly supported by the fast developing ICT infrastructures. Such workflow includes the communication system, the data downloading and treatment, the post-processing and the visualization of the information gathered by the observations. GRID technology may greatly help in providing a remote control of the entire flow of information associated with the observational instruments, from the raw data measured by the sensor at sea (i.e. temperature, salinity, current velocity) to the data-processing software running on the researcher's laptop. In particular, interactive applications of the GRID technology could support the management of the complex workflow related to the instrument interconnections (i.e. buoys, floats, autonomous vehicles), to the eventual technical problems bound to appear intermittently and the subsequent NRT corrections and/or adjustments of the sensors. Moreover, the communication to operative structures such as the Civil Protection, Coast Guards or local/regional administrations represents a composite multi-task process that involves different actors and that could be successfully integrated in a GRID environment. We will present the activity done so far and planned in the framework of the DORII EU-FP7 project [4] concerning the GRID integration of the MedArgo floats managed by

  11. The development and performance of smud grid-connected photovoltaic projects

    SciTech Connect

    Osborn, D.E.; Collier, D.E.

    1995-11-01

    The utility grid-connected market has been identified as a key market to be developed to accelerate the commercialization of photovoltaics. The Sacramento Municipal Utility District (SMUD) has completed the first two years of a continuing commercialization effort based on two years of a continuing commercialization effort based on the sustained, orderly development of the grid-connected, utility PV market. This program is aimed at developing the experience needed to successfully integrate PV as distributed generation into the utility system and to stimulate the collaborative processes needed to accelerate the cost reductions necessary for PV to be cost-effective in these applications by the year 2000. In the first two years, SMUD has installed over 240 residential and commercial building, grid-connected, rooftop, {open_quotes}PV Pioneer{close_quotes} systems totaling over 1MW of capacity and four substation sited, grid-support PV systems totaling 600 kW bringing the SMUD distributed PV power systems to over 3.7 MW. The 1995 SMUD PV Program will add another approximately 800 kW of PV systems to the District`s distributed PV power system. SMUD also established a partnership with its customers through the PV Pioneer {open_quotes}green pricing{close_quotes} program to advance PV commercialization.

  12. Comparative Study of Standards for Grid-Connected Wind Power Plant in China and the U.S.

    SciTech Connect

    Gao, Wenzhong; Tian, Tian; Muljadi, Eduard; Zhang, Yincheng; Miller, Mackay; Wang, Weisheng; Wang, Jing

    2015-10-06

    The rapid deployment of wind power has made grid integration and operational issues focal points in industry discussions and research. Compliance with grid connection standards for wind power plants (WPP) is crucial to ensuring the safe and stable operation of the electric power grid. The standards for grid-connected WPPs in China and the United States are compared in this paper to facilitate further improvements to the standards and enhance the development of wind power equipment. Detailed analyses in power quality, low-voltage ride-through capability, active power control, reactive power control, voltage control, and wind power forecasting are provided to enhance the understanding of grid codes in the two largest markets of wind power.

  13. Residential photovoltaic power conditioning technology for grid connected applications

    NASA Technical Reports Server (NTRS)

    Key, T. S.; Klein, J. W.

    1982-01-01

    Major advances in photovoltaic (PV) Power Conditioning (PC) with respect to performance and low-cost potential have been made. Solutions have been obtained to interface and control problems related to adapting available inverter designs to the grid-connected, residential photovoltaic experiments. A description is presented to contributing research and development activities. Attention is given to aspects of residential systems experience, conceptual design studies, questions of optimum topology development, and promising advanced designs for residential PV provided by development efforts of the private sector.

  14. Connecting Your Solar Electric System to the Utility Grid: Better Buildings Series Solar Electric Fact Sheet

    SciTech Connect

    Not Available

    2002-07-01

    In recent years, the number of solar-powered homes connected to the local utility grid has increased dramatically. These''grid-connected'' buildings have solar electric panels or''modules'' that provide some or even most of their power, while still being connected to the local utility. This fact sheet provides information on connecting your solar electric system to the utility grid, including information on net metering.

  15. Balancing Area Coordination: Efficiently Integrating Renewable Energy Into the Grid, Greening the Grid

    SciTech Connect

    Katz, Jessica; Denholm, Paul; Cochran, Jaquelin

    2015-06-01

    Greening the Grid provides technical assistance to energy system planners, regulators, and grid operators to overcome challenges associated with integrating variable renewable energy into the grid. Coordinating balancing area operation can promote more cost and resource efficient integration of variable renewable energy, such as wind and solar, into power systems. This efficiency is achieved by sharing or coordinating balancing resources and operating reserves across larger geographic boundaries.

  16. 30 CFR 57.12023 - Guarding electrical connections and resistor grids.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Guarding electrical connections and resistor... NONMETAL MINES Electricity Surface and Underground § 57.12023 Guarding electrical connections and resistor grids. Electrical connections and resistor grids that are difficult or impractical to insulate shall...

  17. 30 CFR 56.12023 - Guarding electrical connections and resistor grids.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Guarding electrical connections and resistor... MINES Electricity § 56.12023 Guarding electrical connections and resistor grids. Electrical connections and resistor grids that are difficult or impractical to insulate shall be guarded, unless...

  18. 30 CFR 56.12023 - Guarding electrical connections and resistor grids.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Guarding electrical connections and resistor... MINES Electricity § 56.12023 Guarding electrical connections and resistor grids. Electrical connections and resistor grids that are difficult or impractical to insulate shall be guarded, unless...

  19. 30 CFR 56.12023 - Guarding electrical connections and resistor grids.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Guarding electrical connections and resistor... MINES Electricity § 56.12023 Guarding electrical connections and resistor grids. Electrical connections and resistor grids that are difficult or impractical to insulate shall be guarded, unless...

  20. 30 CFR 57.12023 - Guarding electrical connections and resistor grids.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Guarding electrical connections and resistor... NONMETAL MINES Electricity Surface and Underground § 57.12023 Guarding electrical connections and resistor grids. Electrical connections and resistor grids that are difficult or impractical to insulate shall...

  1. 30 CFR 57.12023 - Guarding electrical connections and resistor grids.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Guarding electrical connections and resistor... NONMETAL MINES Electricity Surface and Underground § 57.12023 Guarding electrical connections and resistor grids. Electrical connections and resistor grids that are difficult or impractical to insulate shall...

  2. 30 CFR 56.12023 - Guarding electrical connections and resistor grids.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Guarding electrical connections and resistor... MINES Electricity § 56.12023 Guarding electrical connections and resistor grids. Electrical connections and resistor grids that are difficult or impractical to insulate shall be guarded, unless...

  3. 30 CFR 56.12023 - Guarding electrical connections and resistor grids.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Guarding electrical connections and resistor... MINES Electricity § 56.12023 Guarding electrical connections and resistor grids. Electrical connections and resistor grids that are difficult or impractical to insulate shall be guarded, unless...

  4. 30 CFR 57.12023 - Guarding electrical connections and resistor grids.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Guarding electrical connections and resistor... NONMETAL MINES Electricity Surface and Underground § 57.12023 Guarding electrical connections and resistor grids. Electrical connections and resistor grids that are difficult or impractical to insulate shall...

  5. 30 CFR 57.12023 - Guarding electrical connections and resistor grids.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Guarding electrical connections and resistor... NONMETAL MINES Electricity Surface and Underground § 57.12023 Guarding electrical connections and resistor grids. Electrical connections and resistor grids that are difficult or impractical to insulate shall...

  6. Performance model for grid-connected photovoltaic inverters.

    SciTech Connect

    Boyson, William Earl; Galbraith, Gary M.; King, David L.; Gonzalez, Sigifredo

    2007-09-01

    This document provides an empirically based performance model for grid-connected photovoltaic inverters used for system performance (energy) modeling and for continuous monitoring of inverter performance during system operation. The versatility and accuracy of the model were validated for a variety of both residential and commercial size inverters. Default parameters for the model can be obtained from manufacturers specification sheets, and the accuracy of the model can be further refined using measurements from either well-instrumented field measurements in operational systems or using detailed measurements from a recognized testing laboratory. An initial database of inverter performance parameters was developed based on measurements conducted at Sandia National Laboratories and at laboratories supporting the solar programs of the California Energy Commission.

  7. Mapping unstructured grid problems to the connection machine

    NASA Technical Reports Server (NTRS)

    Hammond, Steven W.; Schreiber, Robert

    1990-01-01

    We present a highly parallel graph mapping technique that enables one to solve unstructured grid problems on massively parallel computers. Many implicit and explicit methods for solving discretizated partial differential equations require each point in the discretization to exchange data with its neighboring points every time step or iteration. The time spent communicating can limit the high performance promised by massively parallel computing. To eliminate this bottleneck, we map the graph of the irregular problem to the graph representing the interconnection topology of the computer such that the sum of the distances that the messages travel is minimized. We show that, in comparison to a naive assignment of processors, our heuristic mapping algorithm significantly reduces the communication time on the Connection Machine, CM-2.

  8. RETHINKING THE FUTURE GRID: INTEGRATED NUCLEAR-RENEWABLE ENERGY SYSTEMS

    SciTech Connect

    S.M. Bragg-Sitton; R. Boardman

    2014-12-01

    integrate two or more energy resources to generate two or more products, one of which must be an energy commodity, such as electricity or transportation fuel. Subsystems would be integrated ‘‘behind’’ the electrical transmission bus and would be comprised of two or more energy conversion subsystems that have traditionally been separate or isolated. Energy flows would be dynamically apportioned as necessary to meet grid demand via a single, highly responsive connection to the grid that provides dispatchable electricity while capital-intensive generation assets operate at full capacity. Candidate region-specific hybrid energy systems selected for further study and figures of merit that will be used to assess system performance will be presented.

  9. AC HTS Transmission Cable for Integration into the Future EHV Grid of the Netherlands

    NASA Astrophysics Data System (ADS)

    Zuijderduin, R.; Chevtchenko, O.; Smit, J. J.; Aanhaanen, G.; Melnik, I.; Geschiere, A.

    Due to increasing power demand, the electricity grid of the Netherlands is changing. The future grid must be capable to transmit all the connected power. Power generation will be more decentralized like for instance wind parks connected to the grid. Furthermore, future large scale production units are expected to be installed near coastal regions. This creates some potential grid issues, such as: large power amounts to be transmitted to consumers from west to east and grid stability. High temperature superconductors (HTS) can help solving these grid problems. Advantages to integrate HTS components at Extra High Voltage (EHV) and High Voltage (HV) levels are numerous: more power with less losses and less emissions, intrinsic fault current limiting capability, better control of power flow, reduced footprint, etc. Today's main obstacle is the relatively high price of HTS. Nevertheless, as the price goes down, initial market penetration for several HTS components is expected by year 2015 (e.g.: cables, fault current limiters). In this paper we present a design of intrinsically compensated EHV HTS cable for future grid integration. Discussed are the parameters of such cable providing an optimal power transmission in the future network.

  10. Aggregation server for grid-integrated vehicles

    DOEpatents

    Kempton, Willett

    2015-05-26

    Methods, systems, and apparatus for aggregating electric power flow between an electric grid and electric vehicles are disclosed. An apparatus for aggregating power flow may include a memory and a processor coupled to the memory to receive electric vehicle equipment (EVE) attributes from a plurality of EVEs, aggregate EVE attributes, predict total available capacity based on the EVE attributes, and dispatch at least a portion of the total available capacity to the grid. Power flow may be aggregated by receiving EVE operational parameters from each EVE, aggregating the received EVE operational parameters, predicting total available capacity based on the aggregated EVE operational parameters, and dispatching at least a portion of the total available capacity to the grid.

  11. Multipurpose Power Converter for Non-Grid-Connected Microsystems

    NASA Astrophysics Data System (ADS)

    Vovos, Panagis N.; Georgakas, Konstantinos G.

    2015-04-01

    The aim of this paper is to present a multipurpose converter, appropriate for non-grid-connected microsystems, which are prone to harmonic distortion. The converter suppresses harmonics by injecting mirror harmonics in the modulation stage. An important property is that it continuously monitors and significantly reduces the harmonic content without the use of active or passive low-frequency filters. This is under constant switching frequency, no matter if the harmonics are mainly created by the source, the loads or even its own operation. The converter is regulating output voltage using typical fuzzy control. The two types of control (harmonic and voltage) do not seem to affect each other during operation. Furthermore, it can supply either dc or ac loads from a dc source. The versatility of the converter is a useful property for remote or mobile micropower systems, where neither sources nor loads are of a single type. The converter has been tested successfully for a combination of harmonic-injecting electric appliances and various load step changes.

  12. Optimal reactive power control of grid connected photovoltaic resources

    NASA Astrophysics Data System (ADS)

    Trimble, Joshua Ryan

    As more photovoltaic distributed generation resources are installed on distribution power systems, selective control of the inverters connecting the DC power sources presents the opportunity to supply both real and reactive power at the point of common coupling. This thesis presents a simulated distribution system with individually controlled PV resources with the objective of minimizing total system losses while operating at the maximum power point and below the simulated rating of the associated inverters. The control strategy assumes the characteristics of the distribution system are known and solves for the optimal power flow operating point. The ability of each PV source to provide real and reactive power varies instantaneously as irradiance changes, so the operating point for each resource must be constantly recalculated and adjusted. The assumption of known system paramaters can be justified in a SmartGrid context, and a solution based on overall system power flow should be considered as a benchmark for any other state estimation or local control approaches.

  13. Market-Based Indian Grid Integration Study Options: Preprint

    SciTech Connect

    Stoltenberg, B.; Clark, K.; Negi, S. K.

    2012-03-01

    The Indian state of Gujarat is forecasting solar and wind generation expansion from 16% to 32% of installed generation capacity by 2015. Some states in India are already experiencing heavy wind power curtailment. Understanding how to integrate variable generation (VG) into the grid is of great interest to local transmission companies and India's Ministry of New and Renewable Energy. This paper describes the nature of a market-based integration study and how this approach, while new to Indian grid operation and planning, is necessary to understand how to operate and expand the grid to best accommodate the expansion of VG. Second, it discusses options in defining a study's scope, such as data granularity, generation modeling, and geographic scope. The paper also explores how Gujarat's method of grid operation and current system reliability will affect how an integration study can be performed.

  14. Artificial Bee Colony Algorithm for Transient Performance Augmentation of Grid Connected Distributed Generation

    NASA Astrophysics Data System (ADS)

    Chatterjee, A.; Ghoshal, S. P.; Mukherjee, V.

    In this paper, a conventional thermal power system equipped with automatic voltage regulator, IEEE type dual input power system stabilizer (PSS) PSS3B and integral controlled automatic generation control loop is considered. A distributed generation (DG) system consisting of aqua electrolyzer, photovoltaic cells, diesel engine generator, and some other energy storage devices like flywheel energy storage system and battery energy storage system is modeled. This hybrid distributed system is connected to the grid. While integrating this DG with the onventional thermal power system, improved transient performance is noticed. Further improvement in the transient performance of this grid connected DG is observed with the usage of superconducting magnetic energy storage device. The different tunable parameters of the proposed hybrid power system model are optimized by artificial bee colony (ABC) algorithm. The optimal solutions offered by the ABC algorithm are compared with those offered by genetic algorithm (GA). It is also revealed that the optimizing performance of the ABC is better than the GA for this specific application.

  15. Interim Test Procedures for Evaluating Electrical Performance and Grid Integration of Vehicle-to-Grid Applications

    SciTech Connect

    Chakraborty, S.; Kramer, W.; Kroposki, B.; Martin, G.; McNutt, P.; Kuss, M.; Markel, T.; Hoke, A.

    2011-06-01

    The objective of this report is to provide a test plan for V2G testing. The test plan is designed to test and evaluate the vehicle's power electronics capability to provide power to the grid, and to evaluate the vehicle's ability to connect and disconnect from the utility according to a subset of the IEEE Std. 1547 tests.

  16. School Finance and Technology: A Case Study Using Grid and Group Theory to Explore the Connections

    ERIC Educational Resources Information Center

    Case, Stephoni; Harris, Edward L.

    2014-01-01

    Using grid and group theory (Douglas 1982, 2011), the study described in this article examined the intersections of technology and school finance in four schools located in districts differing in size, wealth, and commitment to technology integration. In grid and group theory, grid refers to the degree to which policies and role prescriptions…

  17. Integrating Variable Renewable Energy into the Grid: Key Issues, Greening the Grid

    SciTech Connect

    Katz, Jessica; Cochran, Jaquelin

    2015-05-01

    To foster sustainable, low-emission development, many countries are establishing ambitious renewable energy targets for their electricity supply. Because solar and wind tend to be more variable and uncertain than conventional sources, meeting these targets will involve changes to power system planning and operations. Grid integration is the practice of developing efficient ways to deliver variable renewable energy (VRE) to the grid. Good integration methods maximize the cost-effectiveness of incorporating VRE into the power system while maintaining or increasing system stability and reliability. When considering grid integration, policy makers, regulators, and system operators consider a variety of issues, which can be organized into four broad topics: New Renewable Energy Generation, New Transmission, Increased System Flexibility, Planning for a High RE Future.

  18. Role of Smart Grids in Integrating Renewable Energy

    SciTech Connect

    Speer, B.; Miller, M.; Schaffer, W.; Gueran, L.; Reuter, A.; Jang, B.; Widegren, K.

    2015-05-27

    This report was prepared for the International Smart Grid Action Network (ISGAN), which periodically publishes briefs and discussion papers on key topics of smart grid development globally. The topic of this report was selected by a multilateral group of national experts participating in ISGAN Annex 4, a working group that aims to produce synthesis insights for decision makers. This report is an update of a 2012 ISGAN Annex 4 report entitled “Smart Grid Contributions to Variable Renewable Resource Integration.” That report and other past publications of ISGAN Annexes can be found at www.iea-isgan.org and at www.cleanenergysolutions.org.

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

    SciTech Connect

    Zdeborova, Lenka; Backhaus, Scott; Chertkov, Michael

    2009-01-01

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

  20. Physiological integration of connected balsam poplar ramets.

    PubMed

    Adonsou, Kokouvi Emmanuel; DesRochers, Annie; Tremblay, Francine

    2016-07-01

    Clonal integration between ramets can be an ecological advantage of clonal plant species in environments where resources are patchily distributed. We investigated physiological integration among Populus balsamifera L. ramets under drought stress in order to demonstrate water sharing between connected ramets. Pairs of connected ramets were grown in separate pots in the greenhouse where half of ramets had the parental root connection severed and half were left intact. Drought stress was applied to one ramet, and growth, specific leaf area (SLA), net photosynthesis, stomatal conductance, leaf water potential and carbon isotopic composition (δ(13)C) were measured after an 8-week growing period. Droughted ramets connected to watered ramets were able to maintain high gas exchange activity and water potential, similar to watered ramets. Leaf water potential and SLA results showed that the root connection was more beneficial for proximal compared with distal ramets. The parental root connection also allowed droughted ramets to discriminate more against (13)C compared with severed ramets. In conclusion, this study shows compelling evidence of physiological integration of connected P. balsamifera ramets through water sharing. PMID:26843209

  1. Physiological integration of connected balsam poplar ramets.

    PubMed

    Adonsou, Kokouvi Emmanuel; DesRochers, Annie; Tremblay, Francine

    2016-07-01

    Clonal integration between ramets can be an ecological advantage of clonal plant species in environments where resources are patchily distributed. We investigated physiological integration among Populus balsamifera L. ramets under drought stress in order to demonstrate water sharing between connected ramets. Pairs of connected ramets were grown in separate pots in the greenhouse where half of ramets had the parental root connection severed and half were left intact. Drought stress was applied to one ramet, and growth, specific leaf area (SLA), net photosynthesis, stomatal conductance, leaf water potential and carbon isotopic composition (δ(13)C) were measured after an 8-week growing period. Droughted ramets connected to watered ramets were able to maintain high gas exchange activity and water potential, similar to watered ramets. Leaf water potential and SLA results showed that the root connection was more beneficial for proximal compared with distal ramets. The parental root connection also allowed droughted ramets to discriminate more against (13)C compared with severed ramets. In conclusion, this study shows compelling evidence of physiological integration of connected P. balsamifera ramets through water sharing.

  2. Optimal Wind Energy Integration in Large-Scale Electric Grids

    NASA Astrophysics Data System (ADS)

    Albaijat, Mohammad H.

    The major concern in electric grid operation is operating under the most economical and reliable fashion to ensure affordability and continuity of electricity supply. This dissertation investigates the effects of such challenges, which affect electric grid reliability and economic operations. These challenges are: 1. Congestion of transmission lines, 2. Transmission lines expansion, 3. Large-scale wind energy integration, and 4. Phaser Measurement Units (PMUs) optimal placement for highest electric grid observability. Performing congestion analysis aids in evaluating the required increase of transmission line capacity in electric grids. However, it is necessary to evaluate expansion of transmission line capacity on methods to ensure optimal electric grid operation. Therefore, the expansion of transmission line capacity must enable grid operators to provide low-cost electricity while maintaining reliable operation of the electric grid. Because congestion affects the reliability of delivering power and increases its cost, the congestion analysis in electric grid networks is an important subject. Consequently, next-generation electric grids require novel methodologies for studying and managing congestion in electric grids. We suggest a novel method of long-term congestion management in large-scale electric grids. Owing to the complication and size of transmission line systems and the competitive nature of current grid operation, it is important for electric grid operators to determine how many transmission lines capacity to add. Traditional questions requiring answers are "Where" to add, "How much of transmission line capacity" to add, and "Which voltage level". Because of electric grid deregulation, transmission lines expansion is more complicated as it is now open to investors, whose main interest is to generate revenue, to build new transmission lines. Adding a new transmission capacity will help the system to relieve the transmission system congestion, create

  3. GPCALMA: A Tool For Mammography With A GRID-Connected Distributed Database

    NASA Astrophysics Data System (ADS)

    Bottigli, U.; Cerello, P.; Cheran, S.; Delogu, P.; Fantacci, M. E.; Fauci, F.; Golosio, B.; Lauria, A.; Lopez Torres, E.; Magro, R.; Masala, G. L.; Oliva, P.; Palmiero, R.; Raso, G.; Retico, A.; Stumbo, S.; Tangaro, S.

    2003-09-01

    The GPCALMA (Grid Platform for Computer Assisted Library for MAmmography) collaboration involves several departments of physics, INFN (National Institute of Nuclear Physics) sections, and italian hospitals. The aim of this collaboration is developing a tool that can help radiologists in early detection of breast cancer. GPCALMA has built a large distributed database of digitised mammographic images (about 5500 images corresponding to 1650 patients) and developed a CAD (Computer Aided Detection) software which is integrated in a station that can also be used to acquire new images, as archive and to perform statistical analysis. The images (18×24 cm2, digitised by a CCD linear scanner with a 85 μm pitch and 4096 gray levels) are completely described: pathological ones have a consistent characterization with radiologist's diagnosis and histological data, non pathological ones correspond to patients with a follow up at least three years. The distributed database is realized throught the connection of all the hospitals and research centers in GRID tecnology. In each hospital local patients digital images are stored in the local database. Using GRID connection, GPCALMA will allow each node to work on distributed database data as well as local database data. Using its database the GPCALMA tools perform several analysis. A texture analysis, i.e. an automated classification on adipose, dense or glandular texture, can be provided by the system. GPCALMA software also allows classification of pathological features, in particular massive lesions (both opacities and spiculated lesions) analysis and microcalcification clusters analysis. The detection of pathological features is made using neural network software that provides a selection of areas showing a given "suspicion level" of lesion occurrence. The performance of the GPCALMA system will be presented in terms of the ROC (Receiver Operating Characteristic) curves. The results of GPCALMA system as "second reader" will also

  4. Integrating Grid Services into the Cray XT4 Environment

    SciTech Connect

    NERSC; Cholia, Shreyas; Lin, Hwa-Chun Wendy

    2009-05-01

    The 38640 core Cray XT4"Franklin" system at the National Energy Research Scientific Computing Center (NERSC) is a massively parallel resource available to Department of Energy researchers that also provides on-demand grid computing to the Open Science Grid. The integration of grid services on Franklin presented various challenges, including fundamental differences between the interactive and compute nodes, a stripped down compute-node operating system without dynamic library support, a shared-root environment and idiosyncratic application launching. Inour work, we describe how we resolved these challenges on a running, general-purpose production system to provide on-demand compute, storage, accounting and monitoring services through generic grid interfaces that mask the underlying system-specific details for the end user.

  5. Energy efficiency design strategies for buildings with grid-connected photovoltaic systems

    NASA Astrophysics Data System (ADS)

    Yimprayoon, Chanikarn

    The building sector in the United States represents more than 40% of the nation's energy consumption. Energy efficiency design strategies and renewable energy are keys to reduce building energy demand. Grid-connected photovoltaic (PV) systems installed on buildings have been the fastest growing market in the PV industry. This growth poses challenges for buildings qualified to serve in this market sector. Electricity produced from solar energy is intermittent. Matching building electricity demand with PV output can increase PV system efficiency. Through experimental methods and case studies, computer simulations were used to investigate the priorities of energy efficiency design strategies that decreased electricity demand while producing load profiles matching with unique output profiles from PV. Three building types (residential, commercial, and industrial) of varying sizes and use patterns located in 16 climate zones were modeled according to ASHRAE 90.1 requirements. Buildings were analyzed individually and as a group. Complying with ASHRAE energy standards can reduce annual electricity consumption at least 13%. With energy efficiency design strategies, the reduction could reach up to 65%, making it possible for PV systems to meet reduced demands in residential and industrial buildings. The peak electricity demand reduction could be up to 71% with integration of strategies and PV. Reducing lighting power density was the best single strategy with high overall performances. Combined strategies such as zero energy building are also recommended. Electricity consumption reductions are the sum of the reductions from strategies and PV output. However, peak electricity reductions were less than their sum because they reduced peak at different times. The potential of grid stress reduction is significant. Investment incentives from government and utilities are necessary. The PV system sizes on net metering interconnection should not be limited by legislation existing in

  6. Recent Developments in Grid Generation and Force Integration Technology for Overset Grids

    NASA Technical Reports Server (NTRS)

    Chan, William M.; VanDalsem, William R. (Technical Monitor)

    1994-01-01

    Recent developments in algorithms and software tools for generating overset grids for complex configurations are described. These include the overset surface grid generation code SURGRD and version 2.0 of the hyperbolic volume grid generation code HYPGEN. The SURGRD code is in beta test mode where the new features include the capability to march over a collection of panel networks, a variety of ways to control the side boundaries and the marching step sizes and distance, a more robust projection scheme and an interpolation option. New features in version 2.0 of HYPGEN include a wider range of boundary condition types. The code also allows the user to specify different marching step sizes and distance for each point on the surface grid. A scheme that takes into account of the overlapped zones on the body surface for the purpose of forces and moments computation is also briefly described, The process involves the following two software modules: MIXSUR - a composite grid generation module to produce a collection of quadrilaterals and triangles on which pressure and viscous stresses are to be integrated, and OVERINT - a forces and moments integration module.

  7. Smart Grid Integrity Attacks: Characterizations and Countermeasures

    SciTech Connect

    Annarita Giani; Eilyan Bitar; Miles McQueen; Pramod Khargonekar; Kameshwar Poolla

    2011-10-01

    Real power injections at loads and generators, and real power flows on selected lines in a transmission network are monitored, transmitted over a SCADA network to the system operator, and used in state estimation algorithms to make dispatch, re-balance and other energy management system [EMS] decisions. Coordinated cyber attacks of power meter readings can be arranged to be undetectable by any bad data detection algorithm. These unobservable attacks present a serious threat to grid operations. Of particular interest are sparse attacks that involve the compromise of a modest number of meter readings. An efficient algorithm to find all unobservable attacks [under standard DC load flow approximations] involving the compromise of exactly two power injection meters and an arbitrary number of power meters on lines is presented. This requires O(n2m) flops for a power system with n buses and m line meters. If all lines are metered, there exist canonical forms that characterize all 3, 4, and 5-sparse unobservable attacks. These can be quickly detected in power systems using standard graph algorithms. Known secure phase measurement units [PMUs] can be used as countermeasures against an arbitrary collection of cyber attacks. Finding the minimum number of necessary PMUs is NP-hard. It is shown that p + 1 PMUs at carefully chosen buses are sufficient to neutralize a collection of p cyber attacks.

  8. Optimal system sizing in grid-connected photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Simoens, H. M.; Baert, D. H.; de Mey, G.

    A costs/benefits analysis for optimizing the combination of photovoltaic (PV) panels, batteries and an inverter for grid interconnected systems at a 500 W/day Belgian residence is presented. It is assumed that some power purchases from the grid will always be necessary, and that excess PV power can be fed into the grid. A minimal value for the cost divided by the performance is defined for economic optimization. Shortages and excesses are calculated for PV panels of 0.5-10 kWp output, with consideration given to the advantages of a battery back-up. The minimal economic value is found to increase with the magnitude of PV output, and an inverter should never be rated at more than half the array maximum output. A maximum panel size for the Belgian residence is projected to be 6 kWp.

  9. Redefining What's Possible for Renewable Energy: Grid Integration

    SciTech Connect

    Cochran, Jaquelin; Milligan, Michael; Bloom, Aaron; Lopez, Anthony; Mai, Trieu

    2015-01-22

    The Energy Department's National Renewable Energy Laboratory (NREL) is spearheading engineering innovations that will help optimize the entire energy system, and the lab's analysis capabilities complement that engineering work by identifying ways to integrate renewable energy effectively and economically. This 3-minute video shows how NREL research and analysis are redefining what’s possible for renewable energy on the grid.

  10. COMPARING UTILITY CONNECTED TO STAND ALONE MICRO-GRIDS: FROM THE VIEWPOINT OF A UTILITY ENGINEER

    SciTech Connect

    Hoffman, Michael G.; Russo, Bryan J.

    2011-06-23

    Project examples of grid connected micro grid & example of grid isolated micro grid: drivers – economic, environmental and financial tools to plan/design modeling software resource options, tools to plan/design generation types, fuel options and services to provide smooth transitions required equipment and software controls minimal expense to maximum functionality, real time operational interfaces, getting it built real world complications and advice. This paper is an attempt to present a broad overview of micro grids, project examples, modeling tools, technology options, practical and business insights to enable those interested in micro-grids to quickly come up to speed on the basics and potentially move forward on their own projects with the tools and resources presented. Knowledge and experience with electrical distribution systems will make such an effort easier.

  11. Integrating heterogeneous rules-engine technologies with caGrid.

    PubMed

    Saltz, Joel H; Oster, Scott; Hastings, Shannon L; Langella, Stephen; Ervin, David; Payne, Philip R O

    2007-01-01

    The use of rules-engines spans multiple computational and biomedical domains. Within the NCIs caBIG program, the orchestration of grid-based computational workflow has used the BPEL standard. However, recent strategic planning within caBIG has raised questions about the applicability of BPEL for other rule definition and execution scenarios. In response, we have reviewed the current state of rules-engine technologies, and have formulated an architectural model for the integration of heterogeneous rules-engines with caGrid. PMID:18694196

  12. Analysis and Experimental Verification of New Power Flow Control for Grid-Connected Inverter with LCL Filter in Microgrid

    PubMed Central

    Gu, Herong; Guan, Yajuan; Wang, Huaibao; Wei, Baoze; Guo, Xiaoqiang

    2014-01-01

    Microgrid is an effective way to integrate the distributed energy resources into the utility networks. One of the most important issues is the power flow control of grid-connected voltage-source inverter in microgrid. In this paper, the small-signal model of the power flow control for the grid-connected inverter is established, from which it can be observed that the conventional power flow control may suffer from the poor damping and slow transient response. While the new power flow control can mitigate these problems without affecting the steady-state power flow regulation. Results of continuous-domain simulations in MATLAB and digital control experiments based on a 32-bit fixed-point TMS320F2812 DSP are in good agreement, which verify the small signal model analysis and effectiveness of the proposed method. PMID:24672304

  13. Analysis and experimental verification of new power flow control for grid-connected inverter with LCL filter in microgrid.

    PubMed

    Gu, Herong; Guan, Yajuan; Wang, Huaibao; Wei, Baoze; Guo, Xiaoqiang

    2014-01-01

    Microgrid is an effective way to integrate the distributed energy resources into the utility networks. One of the most important issues is the power flow control of grid-connected voltage-source inverter in microgrid. In this paper, the small-signal model of the power flow control for the grid-connected inverter is established, from which it can be observed that the conventional power flow control may suffer from the poor damping and slow transient response. While the new power flow control can mitigate these problems without affecting the steady-state power flow regulation. Results of continuous-domain simulations in MATLAB and digital control experiments based on a 32-bit fixed-point TMS320F2812 DSP are in good agreement, which verify the small signal model analysis and effectiveness of the proposed method. PMID:24672304

  14. Connection technology of HPTO type WECs and DC nano grid in island

    NASA Astrophysics Data System (ADS)

    Wang, Kun-lin; Tian, Lian-fang; You, Ya-ge; Wang, Xiao-hong; Sheng, Song-wei; Zhang, Ya-qun; Ye, Yin

    2016-07-01

    Wave energy fluctuating a great deal endangers the security of power grid especially micro grid in island. A DC nano grid supported by batteries is proposed to smooth the output power of wave energy converters (WECs). Thus, renewable energy converters connected to DC grid is a new subject. The characteristics of WECs are very important to the connection technology of HPTO type WECs and DC nano grid. Hydraulic power take-off system (HPTO) is the core unit of the largest category of WECs, with the functions of supplying suitable damping for a WEC to absorb wave energy, and converting captured wave energy to electricity. The HPTO is divided into a hydraulic energy storage system (HESS) and a hydraulic power generation system (HPGS). A primary numerical model for the HPGS is established in this paper. Three important basic characteristics of the HPGS are deduced, which reveal how the generator load determines the HPGS rotation rate. Therefore, the connector of HPTO type WEC and DC nano grid would be an uncontrollable rectifier with high reliability, also would be a controllable power converter with high efficiency, such as interleaved boost converter-IBC. The research shows that it is very flexible to connect to DC nano grid for WECs, but bypass resistance loads are indispensable for the security of WECs.

  15. Integrating Autonomic Grid Components and Process-Driven Business Applications

    NASA Astrophysics Data System (ADS)

    Weigold, Thomas; Aldinucci, Marco; Danelutto, Marco; Getov, Vladimir

    Today's business applications are increasingly process driven, meaning that the main application logic is executed by a dedicate process engine. In addition, component-oriented software development has been attracting attention for building complex distributed applications. In this paper we present the experiences gained from building a process-driven biometric identification application which makes use of Grid infrastructures via the Grid Component Model (GCM). GCM, besides guaranteeing access to Grid resources, supports autonomic management of notable parallel composite components. This feature is exploited within our biometric identification application to ensure real time identification of fingerprints. Therefore, we briefly introduce the GCM framework and the process engine used, and we describe the implementation of the application using autonomic GCM components. Finally, we summarize the results, experiences, and lessons learned focusing on the integration of autonomic GCM components and the process-driven approach.

  16. Solar energy grid integration systems - Energy storage (SEGIS-ES)

    SciTech Connect

    Ton, Dan; Peek, Georgianne H.; Hanley, Charles; Boyes, John

    2008-05-01

    In late 2007, the U.S. Department of Energy (DOE) initiated a series of studies to address issues related to potential high penetration of distributed photovoltaic (PV) generation systems on our nation’s electric grid. This Renewable Systems Interconnection (RSI) initiative resulted in the publication of 14 reports and an Executive Summary that defined needs in areas related to utility planning tools and business models, new grid architectures and PV systems configurations, and models to assess market penetration and the effects of high-penetration PV systems. As a result of this effort, the Solar Energy Grid Integration Systems (SEGIS) program was initiated in early 2008. SEGIS is an industry-led effort to develop new PV inverters, controllers, and energy management systems that will greatly enhance the utility of distributed PV systems.

  17. Controlling of grid connected photovoltaic lighting system with fuzzy logic

    SciTech Connect

    Saglam, Safak; Ekren, Nazmi; Erdal, Hasan

    2010-02-15

    In this study, DC electrical energy produced by photovoltaic panels is converted to AC electrical energy and an indoor area is illuminated using this energy. System is controlled by fuzzy logic algorithm controller designed with 16 rules. Energy is supplied from accumulator which is charged by photovoltaic panels if its energy would be sufficient otherwise it is supplied from grid. During the 1-week usage period at the semester time, 1.968 kWh energy is used from grid but designed system used 0.542 kWh energy from photovoltaic panels at the experiments. Energy saving is determined by calculations and measurements for one education year period (9 months) 70.848 kWh. (author)

  18. Integrated 3S Technology Used in Urban Grid Management

    NASA Astrophysics Data System (ADS)

    Zhao, H.; Wang, H.; Wu, W.; Wang, C.

    2014-11-01

    Sustainable development requires monitoring the state and changes of the city and providing the appropriate information to users anytime and anywhere. This paper takes Ningbo City as the research area, by utilizing two temporal (March 25, 2012 and November 25, 2013) ZY-3 satellite remote sensing data. 3S technology is used for urban grid management. The remote sensing information extraction of Ningbo City includes: extraction of building change information, extraction of green space change information, extraction of water information and analysis of eutrophication correspondingly. When extracting change information, we take "change information" as a special kind of "geographic information" to study the characteristics of different bands in multi-temporal data, and follow the first law of geography, namely adjacent similar principle. The extracted raster information is further converted into GIS vector format data as a basis for dynamic monitoring of Ningbo Urban Management systems: on the one hand, it can meet the demands of multi-source spatial data analysis (such as: overlay analysis, buffer analysis, etc.); on the other hand, it could meet the requirements of daily urban management. Dynamic monitoring system of Ningbo city management adopts the urban grid management mode. Based on GIS and GPS, grid management can satisfy the urban management mode -someone bear responsibility within the grid, somebody do the task under the supervision of the lattice, and at the same time play the role of remote sensing field surveying. To some extent, integrated 3S technology and urban grid management is a practical alternative of minimizing the uncertainty of remote sensing data and information extraction. With multi-scale and multi-dimensional remote sensing data, 3S integration and the urban grid management can monitor the urban state and its spatial-temporal changes. It's helpful for discovery and analysis of urban problems about resources, environment, ecology and disaster

  19. An integrated security framework for GOSS power grid analytics platform

    SciTech Connect

    Gibson, Tara D.; Ciraci, Selim; Sharma, Poorva; Allwardt, Craig H.; Rice, Mark J.; Akyol, Bora A.

    2014-06-23

    In power grid operations, security is an essential component for any middleware platform. Security protects data against unwanted access as well as cyber attacks. GridOpticsTM Software System (GOSS) is an open source power grid analytics platform that facilitates ease of access between applications and data sources and promotes development of advanced analytical applications. GOSS contains an API that abstracts many of the difficulties in connecting to various heterogeneous data sources. A number of applications and data sources have already been implemented to demonstrate functionality and ease of use. A security framework has been implemented which leverages widely accepted, robust JavaTM security tools in a way such that they can be interchanged as needed. This framework supports the complex fine-grained, access control rules identified for the diverse data sources already in GOSS. Performance and reliability are also important considerations in any power grid architecture. An evaluation is done to determine the overhead cost caused by security within GOSS and ensure minimal impact to performance.

  20. Smart Energy Management and Control for Fuel Cell Based Micro-Grid Connected Neighborhoods

    SciTech Connect

    Dr. Mohammad S. Alam

    2006-03-15

    Fuel cell power generation promises to be an efficient, pollution-free, reliable power source in both large scale and small scale, remote applications. DOE formed the Solid State Energy Conversion Alliance with the intention of breaking one of the last barriers remaining for cost effective fuel cell power generation. The Alliance’s goal is to produce a core solid-state fuel cell module at a cost of no more than $400 per kilowatt and ready for commercial application by 2010. With their inherently high, 60-70% conversion efficiencies, significantly reduced carbon dioxide emissions, and negligible emissions of other pollutants, fuel cells will be the obvious choice for a broad variety of commercial and residential applications when their cost effectiveness is improved. In a research program funded by the Department of Energy, the research team has been investigating smart fuel cell-operated residential micro-grid communities. This research has focused on using smart control systems in conjunction with fuel cell power plants, with the goal to reduce energy consumption, reduce demand peaks and still meet the energy requirements of any household in a micro-grid community environment. In Phases I and II, a SEMaC was developed and extended to a micro-grid community. In addition, an optimal configuration was determined for a single fuel cell power plant supplying power to a ten-home micro-grid community. In Phase III, the plan is to expand this work to fuel cell based micro-grid connected neighborhoods (mini-grid). The economic implications of hydrogen cogeneration will be investigated. These efforts are consistent with DOE’s mission to decentralize domestic electric power generation and to accelerate the onset of the hydrogen economy. A major challenge facing the routine implementation and use of a fuel cell based mini-grid is the varying electrical demand of the individual micro-grids, and, therefore, analyzing these issues is vital. Efforts are needed to determine

  1. An integral conservative gridding-algorithm using Hermitian curve interpolation

    NASA Astrophysics Data System (ADS)

    Volken, Werner; Frei, Daniel; Manser, Peter; Mini, Roberto; Born, Ernst J.; Fix, Michael K.

    2008-11-01

    The problem of re-sampling spatially distributed data organized into regular or irregular grids to finer or coarser resolution is a common task in data processing. This procedure is known as 'gridding' or 're-binning'. Depending on the quantity the data represents, the gridding-algorithm has to meet different requirements. For example, histogrammed physical quantities such as mass or energy have to be re-binned in order to conserve the overall integral. Moreover, if the quantity is positive definite, negative sampling values should be avoided. The gridding process requires a re-distribution of the original data set to a user-requested grid according to a distribution function. The distribution function can be determined on the basis of the given data by interpolation methods. In general, accurate interpolation with respect to multiple boundary conditions of heavily fluctuating data requires polynomial interpolation functions of second or even higher order. However, this may result in unrealistic deviations (overshoots or undershoots) of the interpolation function from the data. Accordingly, the re-sampled data may overestimate or underestimate the given data by a significant amount. The gridding-algorithm presented in this work was developed in order to overcome these problems. Instead of a straightforward interpolation of the given data using high-order polynomials, a parametrized Hermitian interpolation curve was used to approximate the integrated data set. A single parameter is determined by which the user can control the behavior of the interpolation function, i.e. the amount of overshoot and undershoot. Furthermore, it is shown how the algorithm can be extended to multidimensional grids. The algorithm was compared to commonly used gridding-algorithms using linear and cubic interpolation functions. It is shown that such interpolation functions may overestimate or underestimate the source data by about 10-20%, while the new algorithm can be tuned to

  2. Decision making for best cogeneration power integration into a grid

    NASA Astrophysics Data System (ADS)

    Al Asmar, Joseph; Zakhia, Nadim; Kouta, Raed; Wack, Maxime

    2016-07-01

    Cogeneration systems are known to be efficient power systems for their ability to reduce pollution. Their integration into a grid requires simultaneous consideration of the economic and environmental challenges. Thus, an optimal cogeneration power are adopted to face such challenges. This work presents a novelty in selectinga suitable solution using heuristic optimization method. Its aim is to optimize the cogeneration capacity to be installed according to the economic and environmental concerns. This novelty is based on the sensitivity and data analysis method, namely, Multiple Linear Regression (MLR). This later establishes a compromise between power, economy, and pollution, which leads to find asuitable cogeneration power, and further, to be integrated into a grid. The data exploited were the results of the Genetic Algorithm (GA) multi-objective optimization. Moreover, the impact of the utility's subsidy on the selected power is shown.

  3. Direct power control of grid connected PV systems with three level NPC inverter

    SciTech Connect

    Alonso-Martinez, Jaime; Eloy-Garcia, Joaquin; Arnaltes, Santiago

    2010-07-15

    This paper presents the control of a three-level Neutral Point Clamped (NPC) voltage source inverter for grid connected photovoltaic (PV) systems. The control method used is the Extended Direct Power Control (EDPC), which is a generic approach for Direct Power Control (DPC) of multilevel inverters based on geometrical considerations. Maximum Power Point Tracking (MPPT) algorithms, that allow maximal power conversion into the grid, have been included. These methods are capable of extracting maximum power from each of the independent PV arrays connected to each DC link voltage level. The first one is a conventional MPPT which outputs DC link voltage references to EDPC. The second one is based on DPC concept. This new MPPT outputs power increment references to EDPC, thus avoiding the use of a DC link voltage regulator. The whole control system has been tested on a three-level NPC voltage source inverter connected to the grid and results confirm the validity of the method. (author)

  4. Maximum capacity model of grid-connected multi-wind farms considering static security constraints in electrical grids

    NASA Astrophysics Data System (ADS)

    Zhou, W.; Qiu, G. Y.; Oodo, S. O.; He, H.

    2013-03-01

    An increasing interest in wind energy and the advance of related technologies have increased the connection of wind power generation into electrical grids. This paper proposes an optimization model for determining the maximum capacity of wind farms in a power system. In this model, generator power output limits, voltage limits and thermal limits of branches in the grid system were considered in order to limit the steady-state security influence of wind generators on the power system. The optimization model was solved by a nonlinear primal-dual interior-point method. An IEEE-30 bus system with two wind farms was tested through simulation studies, plus an analysis conducted to verify the effectiveness of the proposed model. The results indicated that the model is efficient and reasonable.

  5. GridOPTICS(TM) A Novel Software Framework for Integrating Power Grid Data Storage, Management and Analysis

    SciTech Connect

    Gorton, Ian; Yin, Jian; Akyol, Bora A.; Ciraci, Selim; Critchlow, Terence; Liu, Yan; Gibson, Tara D.; Purohit, Sumit; Sharma, Poorva; Vlachopoulou, Maria

    2013-01-09

    This paper describes the architecture and design of GridOPTICSTM, a novel software framework to integrate a collection of software tools developed by PNNL’s Future Power Grid Initiative (FPGI) into a coherent, powerful operations and planning tool for the power grid of the future. GridOPTICSTM enables plug-and-play of various analysis, modeling and visualization software tools for fast and accurate control of the power grid. To bridge the data access for different control purposes, GridOPTICSTM provides a scalable and thin layer of event processing that hides the complexity of data storage and management. The initial prototype of GridOPTICSTM was demonstrated with several use cases from PNNL’s FPGI.

  6. Method for fabricating solar cells having integrated collector grids

    NASA Technical Reports Server (NTRS)

    Evans, J. C., Jr. (Inventor)

    1979-01-01

    A heterojunction or Schottky barrier photovoltaic device comprising a conductive base metal layer compatible with and coating predominately the exposed surface of the p-type substrate of the device such that a back surface field region is formed at the interface between the device and the base metal layer, a transparent, conductive mixed metal oxide layer in integral contact with the n-type layer of the heterojunction or Schottky barrier device having a metal alloy grid network of the same metal elements of the oxide constituents of the mixed metal oxide layer embedded in the mixed metal oxide layer, an insulating layer which prevents electrical contact between the conductive metal base layer and the transparent, conductive metal oxide layer, and a metal contact means covering the insulating layer and in intimate contact with the metal grid network embedded in the transparent, conductive oxide layer for conducting electrons generated by the photovoltaic process from the device.

  7. Rethinking the Future Grid: Integrated Nuclear Renewable Energy Systems: Preprint

    SciTech Connect

    Bragg-Sitton, S. M.; Boardman, R.; Ruth, M.; Zinaman, O.; Forsberg, C.

    2015-01-01

    The U.S. DOE is supporting research and development that could lead to more efficient utilization of clean energy generation sources, including renewable and nuclear options, to meet both grid demand and thermal energy needs in the industrial sector. One concept under consideration by the DOE-NE and DOE-EERE is tighter coupling of nuclear and renewable energy sources in a manner that better optimizes energy use for the combined electricity, industrial manufacturing, and transportation sectors. This integration concept has been referred to as a 'hybrid system' that is capable of apportioning thermal and electrical energy to first meet the grid demand (with appropriate power conversion systems), then utilizing excess thermal and, in some cases, electrical energy to drive a process that results in an additional product.

  8. Connecting: Integrating Art across the Curriculum. [Multimedia Educational Kit].

    ERIC Educational Resources Information Center

    Unsworth, Jean Morman

    The idea of "connecting" is explored in this multimedia educational kit art for elementary schools. The Connecting series features a teacher's manual, six teacher's guides, and three videotapes based on six primary themes. These themes are: "Rhythms and Patterns"; "Change and Transformation"; "The World Our Minds Invent"; "Maps, Paths and Grids";…

  9. A bilateral integrative health-care knowledge service mechanism based on 'MedGrid'.

    PubMed

    Liu, Chao; Jiang, Zuhua; Zhen, Lu; Su, Hai

    2008-04-01

    Current health-care organizations are encountering impression of paucity of medical knowledge. This paper classifies medical knowledge with new scopes. The discovery of health-care 'knowledge flow' initiates a bilateral integrative health-care knowledge service, and we make medical knowledge 'flow' around and gain comprehensive effectiveness through six operations (such as knowledge refreshing...). Seizing the active demand of Chinese health-care revolution, this paper presents 'MedGrid', which is a platform with medical ontology and knowledge contents service. Each level and detailed contents are described on MedGrid info-structure. Moreover, a new diagnosis and treatment mechanism are formed by technically connecting with electronic health-care records (EHRs). PMID:18325488

  10. Modeling Electric Vehicle Benefits Connected to Smart Grids

    SciTech Connect

    Stadler, Michael; Marnay, Chris; Mendes, Goncalo; Kloess, Maximillian; Cardoso, Goncalo; Mégel, Olivier; Siddiqui, Afzal

    2011-07-01

    Connecting electric storage technologies to smartgrids will have substantial implications in building energy systems. Local storage will enable demand response. Mobile storage devices in electric vehicles (EVs) are in direct competition with conventional stationary sources at the building. EVs will change the financial as well as environmental attractiveness of on-site generation (e.g. PV, or fuel cells). In order to examine the impact of EVs on building energy costs and CO2 emissions in 2020, a distributed-energy-resources adoption problem is formulated as a mixed-integer linear program with minimization of annual building energy costs or CO2 emissions. The mixed-integer linear program is applied to a set of 139 different commercial buildings in California and example results as well as the aggregated economic and environmental benefits are reported. The research shows that considering second life of EV batteries might be very beneficial for commercial buildings.

  11. GDCF - An interactive approach to domain connectivity among systems of overset grids

    NASA Technical Reports Server (NTRS)

    Mccann, Karen M.; Meakin, Robert L.

    1993-01-01

    The graphical domain connectivity function (GDCF) graphical interface, which was designed to address the need to simplify hole cutter shape selection and positioning in order to exploit the computational savings obtainable through the domain connectivity function (DCF) is described. GDCF was used to prepare data for the V22 tilt-rotor geometry, and data input time was decreased by an order of magnitude. The combined use of GDCF and DCF to satisfy domain connectivity requirements for systems of overset grids is found to minimize both human and computational resources.

  12. Experiences of a grid connected solar array energy production

    NASA Astrophysics Data System (ADS)

    Hagymássy, Zoltán; Vántus, András

    2015-04-01

    Solar energy possibilities of Hungary are higher than in Central Europe generally. The Institute for Land Utilisation, Technology and Regional Development of the University of Debrecen installed a photovoltaic (PV) system. The PV system is structured into 3 subsystems (fields). The first subsystem has 24 pieces of Kyocera KC 120 W type modules, the second subsystem has 72 pieces of Siemens ST 40W, and the remaining has 72 pieces of Dunasolar DS 40W In order to be operable independently of each other three inverter modules (SB 2500) had been installed. The recorder can be connected directly to a desktop PC. Operating and meteorological dates are recorded by MS Excel every 15 minutes. The power plant is connected to a weather station, which contents a PT 100 type temperature and humidity combined measuring instrument, a CM 11 pyranometer, and a wind speed measuring instrument. The produced DC, and AC power, together with the produced energy are as well, and the efficiency can be determined for each used PV technology. The measured operating and meteorological dates are collected by Sunny Boy Control, produced by the SMA. The energy productions of the subsystems are measured continually and the subsystems are measured separately. As an expected, the produced energy of polycrystalline -Si PV module and monocrystalline -Si PV was higher than amorphous-Si PV module. It is well known that energy analysis is more suitable for energy balance when we design a system. The air temperature and the temperature of the panels and the global irradiation conditions were measured. In summertime the panel temperature reaches 60-80 degrees in a sunny day. The panel temperatures are in a spring sunny day approximately 30-40 degrees. It can be concluded that the global irradiation is a major impact feature to influence the amount of energy produced. The efficiency depends on several parameters (spectral distribution of the incoming light, temperature values, etc.). The energy efficiency

  13. Adaptive integral method with fast Gaussian gridding for solving combined field integral equations

    NASA Astrophysics Data System (ADS)

    Bakır, O.; Baǧ; Cı, H.; Michielssen, E.

    Fast Gaussian gridding (FGG), a recently proposed nonuniform fast Fourier transform algorithm, is used to reduce the memory requirements of the adaptive integral method (AIM) for accelerating the method of moments-based solution of combined field integral equations pertinent to the analysis of scattering from three-dimensional perfect electrically conducting surfaces. Numerical results that demonstrate the efficiency and accuracy of the AIM-FGG hybrid in comparison to an AIM-accelerated solver, which uses moment matching to project surface sources onto an auxiliary grid, are presented.

  14. Islanding detection technique using wavelet energy in grid-connected PV system

    NASA Astrophysics Data System (ADS)

    Kim, Il Song

    2016-08-01

    This paper proposes a new islanding detection method using wavelet energy in a grid-connected photovoltaic system. The method detects spectral changes in the higher-frequency components of the point of common coupling voltage and obtains wavelet coefficients by multilevel wavelet analysis. The autocorrelation of the wavelet coefficients can clearly identify islanding detection, even in the variations of the grid voltage harmonics during normal operating conditions. The advantage of the proposed method is that it can detect islanding condition the conventional under voltage/over voltage/under frequency/over frequency methods fail to detect. The theoretical method to obtain wavelet energies is evolved and verified by the experimental result.

  15. Integrating Gridded NASA Hydrological Data into CUAHSI HIS

    NASA Technical Reports Server (NTRS)

    Rui, Hualan; Teng, William; Vollmer, Bruce; Mocko, David M.; Beaudoing, Hiroko K.; Whiteaker, Tim; Valentine, David; Maidment, David; Hooper, Richard

    2011-01-01

    The amount of hydrological data available from NASA remote sensing and modeling systems is vast and ever-increasing;but, one challenge persists:increasing the usefulness of these data for, and thus their use by, end user communities. The Hydrology Data and Information Services Center (HDISC), part of the Goddard Earth Sciences DISC, has continually worked to better understand the hydrological data needs of different end users, to thus better able to bridge the gap between NASA data and end user communities. One effective strategy is integrating the data in to end user community tools and environments. There is an ongoing collaborative effort between NASA HDISC, NASA Hydrological Sciences Branch, and CUAHSI to integrate NASA gridded hydrology data in to the CUAHSI Hydrologic Information System (HIS).

  16. How to Integrate Variable Power Source into a Power Grid

    NASA Astrophysics Data System (ADS)

    Asano, Hiroshi

    This paper discusses how to integrate variable power source such as wind power and photovoltaic generation into a power grid. The intermittent renewable generation is expected to penetrate for less carbon intensive power supply system, but it causes voltage control problem in the distribution system, and supply-demand imbalance problem in a whole power system. Cooperative control of customers' energy storage equipment such as water heater with storage tank for reducing inverse power flow from the roof-top PV system, the operation technique using a battery system and the solar radiation forecast for stabilizing output of variable generation, smart charging of plug-in hybrid electric vehicles for load frequency control (LFC), and other methods to integrate variable power source with improving social benefits are surveyed.

  17. Implementation of fuzzy-sliding mode based control of a grid connected photovoltaic system.

    PubMed

    Menadi, Abdelkrim; Abdeddaim, Sabrina; Ghamri, Ahmed; Betka, Achour

    2015-09-01

    The present work describes an optimal operation of a small scale photovoltaic system connected to a micro-grid, based on both sliding mode and fuzzy logic control. Real time implementation is done through a dSPACE 1104 single board, controlling a boost chopper on the PV array side and a voltage source inverter (VSI) on the grid side. The sliding mode controller tracks permanently the maximum power of the PV array regardless of atmospheric condition variations, while The fuzzy logic controller (FLC) regulates the DC-link voltage, and ensures via current control of the VSI a quasi-total transit of the extracted PV power to the grid under a unity power factor operation. Simulation results, carried out via Matlab-Simulink package were approved through experiment, showing the effectiveness of the proposed control techniques. PMID:26243440

  18. Implementation of fuzzy-sliding mode based control of a grid connected photovoltaic system.

    PubMed

    Menadi, Abdelkrim; Abdeddaim, Sabrina; Ghamri, Ahmed; Betka, Achour

    2015-09-01

    The present work describes an optimal operation of a small scale photovoltaic system connected to a micro-grid, based on both sliding mode and fuzzy logic control. Real time implementation is done through a dSPACE 1104 single board, controlling a boost chopper on the PV array side and a voltage source inverter (VSI) on the grid side. The sliding mode controller tracks permanently the maximum power of the PV array regardless of atmospheric condition variations, while The fuzzy logic controller (FLC) regulates the DC-link voltage, and ensures via current control of the VSI a quasi-total transit of the extracted PV power to the grid under a unity power factor operation. Simulation results, carried out via Matlab-Simulink package were approved through experiment, showing the effectiveness of the proposed control techniques.

  19. Photovoltaic Grid-Connected Modeling and Characterization Based on Experimental Results

    PubMed Central

    Humada, Ali M.; Hojabri, Mojgan; Sulaiman, Mohd Herwan Bin; Hamada, Hussein M.; Ahmed, Mushtaq N.

    2016-01-01

    A grid-connected photovoltaic (PV) system operates under fluctuated weather condition has been modeled and characterized based on specific test bed. A mathematical model of a small-scale PV system has been developed mainly for residential usage, and the potential results have been simulated. The proposed PV model based on three PV parameters, which are the photocurrent, IL, the reverse diode saturation current, Io, the ideality factor of diode, n. Accuracy of the proposed model and its parameters evaluated based on different benchmarks. The results showed that the proposed model fitting the experimental results with high accuracy compare to the other models, as well as the I-V characteristic curve. The results of this study can be considered valuable in terms of the installation of a grid-connected PV system in fluctuated climatic conditions. PMID:27035575

  20. Photovoltaic Grid-Connected Modeling and Characterization Based on Experimental Results.

    PubMed

    Humada, Ali M; Hojabri, Mojgan; Sulaiman, Mohd Herwan Bin; Hamada, Hussein M; Ahmed, Mushtaq N

    2016-01-01

    A grid-connected photovoltaic (PV) system operates under fluctuated weather condition has been modeled and characterized based on specific test bed. A mathematical model of a small-scale PV system has been developed mainly for residential usage, and the potential results have been simulated. The proposed PV model based on three PV parameters, which are the photocurrent, IL, the reverse diode saturation current, Io, the ideality factor of diode, n. Accuracy of the proposed model and its parameters evaluated based on different benchmarks. The results showed that the proposed model fitting the experimental results with high accuracy compare to the other models, as well as the I-V characteristic curve. The results of this study can be considered valuable in terms of the installation of a grid-connected PV system in fluctuated climatic conditions. PMID:27035575

  1. Solar Energy Grid Integration Systems -- Energy Storage (SEGIS-ES).

    SciTech Connect

    Hanley, Charles J.; Ton, Dan T.; Boyes, John D.; Peek, Georgianne Huff

    2008-07-01

    This paper describes the concept for augmenting the SEGIS Program (an industry-led effort to greatly enhance the utility of distributed PV systems) with energy storage in residential and small commercial applications (SEGIS-ES). The goal of SEGIS-ES is to develop electrical energy storage components and systems specifically designed and optimized for grid-tied PV applications. This report describes the scope of the proposed SEGIS-ES Program and why it will be necessary to integrate energy storage with PV systems as PV-generated energy becomes more prevalent on the nation's utility grid. It also discusses the applications for which energy storage is most suited and for which it will provide the greatest economic and operational benefits to customers and utilities. Included is a detailed summary of the various storage technologies available, comparisons of their relative costs and development status, and a summary of key R&D needs for PV-storage systems. The report concludes with highlights of areas where further PV-specific R&D is needed and offers recommendations about how to proceed with their development.

  2. Modular Cascaded H-Bridge Multilevel PV Inverter with Distributed MPPT for Grid-Connected Applications

    DOE PAGES

    Xiao, Bailu; Hang, Lijun; Mei, Jun; Riley, Cameron; Tolbert, Leon M.; Ozpineci, Burak

    2014-09-04

    This paper presents a modular cascaded H-bridge multilevel photovoltaic (PV) inverter for single- or three-phase grid-connected applications. The modular cascaded multilevel topology helps to improve the efficiency and flexibility of PV systems. To realize better utilization of PV modules and maximize the solar energy extraction, a distributed maximum power point tracking (MPPT) control scheme is applied to both single-phase and three-phase multilevel inverters, which allows the independent control of each dc-link voltage. For three-phase grid-connected applications, PV mismatches may introduce unbalanced supplied power, leading to unbalanced grid current. To solve this issue, a control scheme with modulation compensation is alsomore » proposed. An experimental three-phase 7-level cascaded H-bridge inverter has been built utilizing 9 H-bridge modules (3 modules per phase). Each H-bridge module is connected to a 185 W solar panel. Simulation and experimental results are presented to verify the feasibility of the proposed approach.« less

  3. Modular Cascaded H-Bridge Multilevel PV Inverter with Distributed MPPT for Grid-Connected Applications

    SciTech Connect

    Xiao, Bailu; Hang, Lijun; Mei, Jun; Riley, Cameron; Tolbert, Leon M.; Ozpineci, Burak

    2014-09-04

    This paper presents a modular cascaded H-bridge multilevel photovoltaic (PV) inverter for single- or three-phase grid-connected applications. The modular cascaded multilevel topology helps to improve the efficiency and flexibility of PV systems. To realize better utilization of PV modules and maximize the solar energy extraction, a distributed maximum power point tracking (MPPT) control scheme is applied to both single-phase and three-phase multilevel inverters, which allows the independent control of each dc-link voltage. For three-phase grid-connected applications, PV mismatches may introduce unbalanced supplied power, leading to unbalanced grid current. To solve this issue, a control scheme with modulation compensation is also proposed. An experimental three-phase 7-level cascaded H-bridge inverter has been built utilizing 9 H-bridge modules (3 modules per phase). Each H-bridge module is connected to a 185 W solar panel. Simulation and experimental results are presented to verify the feasibility of the proposed approach.

  4. Solar energy grid integration systems : final report of the Florida Solar Energy Center Team.

    SciTech Connect

    Ropp, Michael; Gonzalez, Sigifredo; Schaffer, Alan; Katz, Stanley; Perkinson, Jim; Bower, Ward Isaac; Prestero, Mark; Casey, Leo; Moaveni, Houtan; Click, David; Davis, Kristopher; Reedy, Robert; Kuszmaul, Scott S.; Sena-Henderson, Lisa; David, Carolyn; Akhil, Abbas Ali

    2012-03-01

    Initiated in 2008, the Solar Energy Grid Integration Systems (SEGIS) program is a partnership involving the U.S. DOE, Sandia National Laboratories, private sector companies, electric utilities, and universities. Projects supported under the program have focused on the complete-system development of solar technologies, with the dual goal of expanding utility-scale penetration and addressing new challenges of connecting large-scale solar installations in higher penetrations to the electric grid. The Florida Solar Energy Center (FSEC), its partners, and Sandia National Laboratories have successfully collaborated to complete the work under the third and final stage of the SEGIS initiative. The SEGIS program was a three-year, three-stage project that include conceptual design and market analysis in Stage 1, prototype development and testing in Stage 2, and moving toward commercialization in Stage 3. Under this program, the FSEC SEGIS team developed a comprehensive vision that has guided technology development that sets one methodology for merging photovoltaic (PV) and smart-grid technologies. The FSEC team's objective in the SEGIS project is to remove barriers to large-scale general integration of PV and to enhance the value proposition of photovoltaic energy by enabling PV to act as much as possible as if it were at the very least equivalent to a conventional utility power plant. It was immediately apparent that the advanced power electronics of these advanced inverters will go far beyond conventional power plants, making high penetrations of PV not just acceptable, but desirable. This report summarizes a three-year effort to develop, validate and commercialize Grid-Smart Inverters for wider photovoltaic utilization, particularly in the utility sector.

  5. During Running in Place, Grid Cells Integrate Elapsed Time and Distance Run.

    PubMed

    Kraus, Benjamin J; Brandon, Mark P; Robinson, Robert J; Connerney, Michael A; Hasselmo, Michael E; Eichenbaum, Howard

    2015-11-01

    The spatial scale of grid cells may be provided by self-generated motion information or by external sensory information from environmental cues. To determine whether grid cell activity reflects distance traveled or elapsed time independent of external information, we recorded grid cells as animals ran in place on a treadmill. Grid cell activity was only weakly influenced by location, but most grid cells and other neurons recorded from the same electrodes strongly signaled a combination of distance and time, with some signaling only distance or time. Grid cells were more sharply tuned to time and distance than non-grid cells. Many grid cells exhibited multiple firing fields during treadmill running, parallel to the periodic firing fields observed in open fields, suggesting a common mode of information processing. These observations indicate that, in the absence of external dynamic cues, grid cells integrate self-generated distance and time information to encode a representation of experience.

  6. During running in place, grid cells integrate elapsed time and distance run

    PubMed Central

    Kraus, Benjamin J.; Brandon, Mark P.; Robinson, Robert J.; Connerney, Michael A.; Hasselmo, Michael E.; Eichenbaum, Howard

    2015-01-01

    Summary The spatial scale of grid cells may be provided by self-generated motion information or by external sensory information from environmental cues. To determine whether grid cell activity reflects distance traveled or elapsed time independent of external information, we recorded grid cells as animals ran in place on a treadmill. Grid cell activity was only weakly influenced by location but most grid cells and other neurons recorded from the same electrodes strongly signaled a combination of distance and time, with some signaling only distance or time. Grid cells were more sharply tuned to time and distance than non-grid cells. Many grid cells exhibited multiple firing fields during treadmill running, parallel to the periodic firing fields observed in open fields, suggesting a common mode of information processing. These observations indicate that, in the absence of external dynamic cues, grid cells integrate self-generated distance and time information to encode a representation of experience. PMID:26539893

  7. Dynamic analysis of combined photovoltaic source and synchronous generator connected to power grid

    NASA Astrophysics Data System (ADS)

    Mahabal, Divya

    In the world of expanding economy and technology, the energy demand is likely to increase even with the global efforts of saving and increasing energy efficiency. Higher oil prices, effects of greenhouse gases, and concerns over other environmental impacts gave way to Distributed Generation (DG). With adequate awareness and support, DG's can meet these rising energy demands at lower prices compared to conventional methods. Extensive research is taking place in different areas like fuel cells, photovoltaic cells, wind turbines, and gas turbines. DG's when connected to a grid increase the overall efficiency of the power grid. It is believed that three-fifth of the world's electricity would account for renewable energy by middle of 21st century. This thesis presents the dynamic analysis of a grid connected photovoltaic (PV) system and synchronous generator. A grid is considered as an infinite bus. The photovol-taic system and synchronous generator act as small scale distributed energy resources. The output of the photovoltaic system depends on the light intensity, temperature, and irradiance levels of sun. The maximum power point tracking and DC/AC converter are also modeled for the photovoltaic system. The PV system is connected to the grid through DC/AC system. Different combinations of PV and synchronous generator are modeled with the grid to study the dynamics of the proposed system. The dynamics of the test system is analyzed by subjecting the system to several disturbances under various conditions. All modules are individually modeled and con-nected using MATLAB/Simulink software package. Results from the study show that, as the penetration of renewable energy sources like PV increases into the power system, the dynamics of the system becomes faster. When considering cases such as load switching, PV cannot deliver more power as the performance of PV depends on environmental conditions. Synchronous generator in power system can produce the required amount of

  8. Two-loop controller for maximizing performance of a grid-connected photovoltaic - fuel cell hybrid power plant

    NASA Astrophysics Data System (ADS)

    Ro, Kyoungsoo

    The study started with the requirement that a photovoltaic (PV) power source should be integrated with other supplementary power sources whether it operates in a stand-alone or grid-connected mode. First, fuel cells for a backup of varying PV power were compared in detail with batteries and were found to have more operational benefits. Next, maximizing performance of a grid-connected PV-fuel cell hybrid system by use of a two-loop controller was discussed. One loop is a neural network controller for maximum power point tracking, which extracts maximum available solar power from PV arrays under varying conditions of insolation, temperature, and system load. A real/reactive power controller (RRPC) is the other loop. The RRPC meets the system's requirement for real and reactive powers by controlling incoming fuel to fuel cell stacks as well as switching control signals to a power conditioning subsystem. The RRPC is able to achieve more versatile control of real/reactive powers than the conventional power sources since the hybrid power plant does not contain any rotating mass. Results of time-domain simulations prove not only effectiveness of the proposed computer models of the two-loop controller, but also their applicability for use in transient stability analysis of the hybrid power plant. Finally, environmental evaluation of the proposed hybrid plant was made in terms of plant's land requirement and lifetime COsb2 emissions, and then compared with that of the conventional fossil-fuel power generating forms.

  9. Smart electric vehicle (EV) charging and grid integration apparatus and methods

    SciTech Connect

    Gadh, Rajit; Mal, Siddhartha; Prabhu, Shivanand; Chu, Chi-Cheng; Sheikh, Omar; Chung, Ching-Yen; He, Lei; Xiao, Bingjun; Shi, Yiyu

    2015-05-05

    An expert system manages a power grid wherein charging stations are connected to the power grid, with electric vehicles connected to the charging stations, whereby the expert system selectively backfills power from connected electric vehicles to the power grid through a grid tie inverter (if present) within the charging stations. In more traditional usage, the expert system allows for electric vehicle charging, coupled with user preferences as to charge time, charge cost, and charging station capabilities, without exceeding the power grid capacity at any point. A robust yet accurate state of charge (SOC) calculation method is also presented, whereby initially an open circuit voltage (OCV) based on sampled battery voltages and currents is calculated, and then the SOC is obtained based on a mapping between a previously measured reference OCV (ROCV) and SOC. The OCV-SOC calculation method accommodates likely any battery type with any current profile.

  10. PVUSA experience with power conversion for grid-connected photovoltaic systems

    SciTech Connect

    Stolte, W.

    1995-11-01

    The Photovoltaics for Utility Scale Application (PVUSA) project was established to demonstrate photovoltaic (PV) systems in grid-connected utility applications. One of PVUSA`s key objectives is to evaluate the performance, reliability, and cost of the PV balance of system (BOS). Power conditioning units (PCUs) are the interface between the dc PV arrays and the ac utility lines, and have proved to be the most critical element in grid-connected PV systems. There are five different models of PCUs at PVUSA`s Davis and Kerman sites. This report describes the design, testing, performance characteristics, and maintenance history of each of these PCUs. PVUSA required PCUs in the power range 25 kW to 500 kW which could operate automatically and reliably under changing conditions of sunlight and changing conditions on the utility grid. Although a number of manufacturers can provide PCUs in this power range, none of these PCUs have been produced in sufficient quantity to allow refinement of a particular model into the highly reliable unit needed for long-term, unattended operation. Factory tests were useful but limited by the inability to test under full power and changing power conditions. The inability to completely test PCUs at the factory resulted in difficulty during startup, field testing, and subsequent operation. PVUSA has made significant progress in understanding the requirements for PCUs in grid-connected PV applications and improving field performance. This record of PVUSA`s experience with a variety of PCUs is intended to help utilities and their suppliers identify and retain the good performance characteristics of PCUs, and to make improvements where necessary to meet the needs of utilities.

  11. Electricity storage for grid-connected household dwellings with PV panels

    SciTech Connect

    Mulder, Grietus; Six, Daan; Ridder, Fjo De

    2010-07-15

    Classically electricity storage for PV panels is mostly designed for stand-alone applications. In contrast, we focus in this article on houses connected to the grid with a small-scale storage to store a part of the solar power for postponed consumption within the day or the next days. In this way the house owner becomes less dependent on the grid and does only pay for the net shortage of his energy production. Local storage solutions pave the way for many new applications like omitting over-voltage of the line and bridging periods of power-line black-out. Since 2009 using self-consumption of PV energy is publicly encouraged in Germany, which can be realised by electric storage. This paper develops methods to determine the optimal storage size for grid-connected dwellings with PV panels. From measurements in houses we were able to establish calculation rules for sizing the storage. Two situations for electricity storage are covered: - the storage system is an optimum to cover most of the electricity needs; - it is an optimum for covering the peak power need of a dwelling. After these calculation rules a second step is needed to determine the size of the real battery. The article treats the aspects that should be taken into consideration before buying a specific battery like lead-acid and lithium-ion batteries. (author)

  12. Integration and validation of a data grid software

    NASA Astrophysics Data System (ADS)

    Carenton-Madiec, Nicolas; Berger, Katharina; Cofino, Antonio

    2014-05-01

    The Earth System Grid Federation (ESGF) Peer-to-Peer (P2P) is a software infrastructure for the management, dissemination, and analysis of model output and observational data. The ESGF grid is composed with several types of nodes which have different roles. About 40 data nodes host model outputs and datasets using thredds catalogs. About 25 compute nodes offer remote visualization and analysis tools. About 15 index nodes crawl data nodes catalogs and implement faceted and federated search in a web interface. About 15 Identity providers nodes manage accounts, authentication and authorization. Here we will present an actual size test federation spread across different institutes in different countries and a python test suite that were started in December 2013. The first objective of the test suite is to provide a simple tool that helps to test and validate a single data node and its closest index, compute and identity provider peer. The next objective will be to run this test suite on every data node of the federation and therefore test and validate every single node of the whole federation. The suite already implements nosetests, requests, myproxy-logon, subprocess, selenium and fabric python libraries in order to test both web front ends, back ends and security services. The goal of this project is to improve the quality of deliverable in a small developers team context. Developers are widely spread around the world working collaboratively and without hierarchy. This kind of working organization context en-lighted the need of a federated integration test and validation process.

  13. Connections: A Model for Integrated Freshman Year Studies.

    ERIC Educational Resources Information Center

    Olds, Barbara M.; Miller, Ronald L.

    This document describes the development of a project called "Connections," at the Colorado School of Mines. "Connections" is an integrated series of active-learning courses and seminars that allow first-year engineering and science students to connect studies in engineering, physical science, social science, and humanities via a series of…

  14. Coupling Electric Vehicles and Power Grid through Charging-In-Motion and Connected Vehicle Technology

    SciTech Connect

    Li, Jan-Mou; Jones, Perry T; Onar, Omer C; Starke, Michael R

    2014-01-01

    A traffic-assignment-based framework is proposed to model the coupling of transportation network and power grid for analyzing impacts of energy demand from electric vehicles on the operation of power distribution. Although the reverse can be investigated with the proposed framework as well, electricity flowing from a power grid to electric vehicles is the focus of this paper. Major variables in transportation network (including link flows) and power grid (including electricity transmitted) are introduced for the coupling. Roles of charging-in-motion technology and connected vehicle technology have been identified in the framework of supernetwork. A linkage (i.e. individual energy demand) between the two networks is defined to construct the supernetwork. To determine equilibrium of the supernetwork can also answer how many drivers are going to use the charging-in-motion services, in which locations, and at what time frame. An optimal operation plan of power distribution will be decided along the determination simultaneously by which we have a picture about what level of power demand from the grid is expected in locations during an analyzed period. Caveat of the framework and possible applications have also been discussed.

  15. Magnitude and Variability of Controllable Charge Capacity Provided by Grid Connected Plug-in Electric Vehicles

    SciTech Connect

    Scoffield, Don R; Smart, John; Salisbury, Shawn

    2015-03-01

    As market penetration of plug-in electric vehicles (PEV) increases over time, the number of PEVs charging on the electric grid will also increase. As the number of PEVs increases, their ability to collectively impact the grid increases. The idea of a large body of PEVs connected to the grid presents an intriguing possibility. If utilities can control PEV charging, it is possible that PEVs could act as a distributed resource to provide grid services. The technology required to control charging is available for modern PEVs. However, a system for wide-spread implementation of controllable charging, including robust communication between vehicles and utilities, is not currently present. Therefore, the value of controllable charging must be assessed and weighed against the cost of building and operating such as system. In order to grasp the value of PEV charge control to the utility, the following must be understood: 1. The amount of controllable energy and power capacity available to the utility 2. The variability of the controllable capacity from day to day and as the number of PEVs in the market increases.

  16. Islanding the power grid on the transmission level: less connections for more security

    NASA Astrophysics Data System (ADS)

    Mureddu, Mario; Caldarelli, Guido; Damiano, Alfonso; Scala, Antonio; Meyer-Ortmanns, Hildegard

    2016-10-01

    Islanding is known as a management procedure of the power system that is implemented at the distribution level to preserve sensible loads from outages and to guarantee the continuity in electricity supply, when a high amount of distributed generation occurs. In this paper we study islanding on the level of the transmission grid and shall show that it is a suitable measure to enhance energy security and grid resilience. We consider the German and Italian transmission grids. We remove links either randomly to mimic random failure events, or according to a topological characteristic, their so-called betweenness centrality, to mimic an intentional attack and test whether the resulting fragments are self-sustainable. We test this option via the tool of optimized DC power flow equations. When transmission lines are removed according to their betweenness centrality, the resulting islands have a higher chance of being dynamically self-sustainable than for a random removal. Less connections may even increase the grid’s stability. These facts should be taken into account in the design of future power grids.

  17. Islanding the power grid on the transmission level: less connections for more security

    PubMed Central

    Mureddu, Mario; Caldarelli, Guido; Damiano, Alfonso; Scala, Antonio; Meyer-Ortmanns, Hildegard

    2016-01-01

    Islanding is known as a management procedure of the power system that is implemented at the distribution level to preserve sensible loads from outages and to guarantee the continuity in electricity supply, when a high amount of distributed generation occurs. In this paper we study islanding on the level of the transmission grid and shall show that it is a suitable measure to enhance energy security and grid resilience. We consider the German and Italian transmission grids. We remove links either randomly to mimic random failure events, or according to a topological characteristic, their so-called betweenness centrality, to mimic an intentional attack and test whether the resulting fragments are self-sustainable. We test this option via the tool of optimized DC power flow equations. When transmission lines are removed according to their betweenness centrality, the resulting islands have a higher chance of being dynamically self-sustainable than for a random removal. Less connections may even increase the grid’s stability. These facts should be taken into account in the design of future power grids. PMID:27713509

  18. Connectivity

    ERIC Educational Resources Information Center

    Grush, Mary, Ed.

    2006-01-01

    Connectivity has dramatically changed the landscape of higher education IT. From "on-demand" services for net-gen students and advanced eLearning systems for faculty, to high-performance computing grid resources for researchers, IT now provides more networked services than ever to connect campus constituents to each other and to the world.…

  19. Advances in Domain Connectivity for Overset Grids Using the X-Rays Approach

    NASA Technical Reports Server (NTRS)

    Chan, William M.; Kim, Noah; Pandya, Shishir A.

    2012-01-01

    Advances in automation and robustness of the X-rays approach to domain connectivity for overset grids are presented. Given the surface definition for each component that makes up a complex configuration, the determination of hole points with appropriate hole boundaries is automatically and efficiently performed. Improvements made to the original X-rays approach for identifying the minimum hole include an automated closure scheme for hole-cutters with open boundaries, automatic determination of grid points to be considered for blanking by each hole-cutter, and an adaptive X-ray map to economically handle components in close proximity. Furthermore, an automated spatially varying offset of the hole boundary from the minimum hole is achieved using a dual wall-distance function and an orphan point removal iteration process. Results using the new scheme are presented for a number of static and relative motion test cases on a variety of aerospace applications.

  20. Artificial neural networks for control of a grid-connected rectifier/inverter under disturbance, dynamic and power converter switching conditions.

    PubMed

    Li, Shuhui; Fairbank, Michael; Johnson, Cameron; Wunsch, Donald C; Alonso, Eduardo; Proaño, Julio L

    2014-04-01

    Three-phase grid-connected converters are widely used in renewable and electric power system applications. Traditionally, grid-connected converters are controlled with standard decoupled d-q vector control mechanisms. However, recent studies indicate that such mechanisms show limitations in their applicability to dynamic systems. This paper investigates how to mitigate such restrictions using a neural network to control a grid-connected rectifier/inverter. The neural network implements a dynamic programming algorithm and is trained by using back-propagation through time. To enhance performance and stability under disturbance, additional strategies are adopted, including the use of integrals of error signals to the network inputs and the introduction of grid disturbance voltage to the outputs of a well-trained network. The performance of the neural-network controller is studied under typical vector control conditions and compared against conventional vector control methods, which demonstrates that the neural vector control strategy proposed in this paper is effective. Even in dynamic and power converter switching environments, the neural vector controller shows strong ability to trace rapidly changing reference commands, tolerate system disturbances, and satisfy control requirements for a faulted power system.

  1. Detecting Functional Connectivity During Audiovisual Integration with MEG: A Comparison of Connectivity Metrics.

    PubMed

    Ard, Tyler; Carver, Frederick W; Holroyd, Tom; Horwitz, Barry; Coppola, Richard

    2015-08-01

    In typical magnetoencephalography and/or electroencephalography functional connectivity analysis, researchers select one of several methods that measure a relationship between regions to determine connectivity, such as coherence, power correlations, and others. However, it is largely unknown if some are more suited than others for various types of investigations. In this study, the authors investigate seven connectivity metrics to evaluate which, if any, are sensitive to audiovisual integration by contrasting connectivity when tracking an audiovisual object versus connectivity when tracking a visual object uncorrelated with the auditory stimulus. The authors are able to assess the metrics' performances at detecting audiovisual integration by investigating connectivity between auditory and visual areas. Critically, the authors perform their investigation on a whole-cortex all-to-all mapping, avoiding confounds introduced in seed selection. The authors find that amplitude-based connectivity measures in the beta band detect strong connections between visual and auditory areas during audiovisual integration, specifically between V4/V5 and auditory cortices in the right hemisphere. Conversely, phase-based connectivity measures in the beta band as well as phase and power measures in alpha, gamma, and theta do not show connectivity between audiovisual areas. The authors postulate that while beta power correlations detect audiovisual integration in the current experimental context, it may not always be the best measure to detect connectivity. Instead, it is likely that the brain utilizes a variety of mechanisms in neuronal communication that may produce differential types of temporal relationships.

  2. Detecting Functional Connectivity During Audiovisual Integration with MEG: A Comparison of Connectivity Metrics

    PubMed Central

    Carver, Frederick W.; Holroyd, Tom; Horwitz, Barry; Coppola, Richard

    2015-01-01

    Abstract In typical magnetoencephalography and/or electroencephalography functional connectivity analysis, researchers select one of several methods that measure a relationship between regions to determine connectivity, such as coherence, power correlations, and others. However, it is largely unknown if some are more suited than others for various types of investigations. In this study, the authors investigate seven connectivity metrics to evaluate which, if any, are sensitive to audiovisual integration by contrasting connectivity when tracking an audiovisual object versus connectivity when tracking a visual object uncorrelated with the auditory stimulus. The authors are able to assess the metrics' performances at detecting audiovisual integration by investigating connectivity between auditory and visual areas. Critically, the authors perform their investigation on a whole-cortex all-to-all mapping, avoiding confounds introduced in seed selection. The authors find that amplitude-based connectivity measures in the beta band detect strong connections between visual and auditory areas during audiovisual integration, specifically between V4/V5 and auditory cortices in the right hemisphere. Conversely, phase-based connectivity measures in the beta band as well as phase and power measures in alpha, gamma, and theta do not show connectivity between audiovisual areas. The authors postulate that while beta power correlations detect audiovisual integration in the current experimental context, it may not always be the best measure to detect connectivity. Instead, it is likely that the brain utilizes a variety of mechanisms in neuronal communication that may produce differential types of temporal relationships. PMID:25599264

  3. Test results of a HTS power transformer connected to a power grid

    NASA Astrophysics Data System (ADS)

    Kimura, H.; Honda, K.; Hayashi, H.; Tsutsumi, K.; Iwakuma, M.; Funaki, K.; Bohno, T.; Tomioka, A.; Yagi, Y.; Maruyama, H.; Ohashi, K.

    2002-08-01

    A 22 kV/6.9 kV-1 MVA high- Tc superconducting (HTS) power transformer has been developed as a prototype with single-phase part of a 3 MVA HTS power transformer. The prototype unit is cooled by a continuous subcooled liquid nitrogen (LN 2) supply system with cryocoolers. During the field tests, the HTS transformer was connected to a distribution line at Imajuku substation (Kyushu Electric Power Co., Inc.) in Fukuoka, and inrush-current test and a long-term operation test were implemented. The test results demonstrated the HTS power transformer's applicability to a power grid.

  4. Automatic Integration Testbeds validation on Open Science Grid

    NASA Astrophysics Data System (ADS)

    Caballero, J.; Thapa, S.; Gardner, R.; Potekhin, M.

    2011-12-01

    A recurring challenge in deploying high quality production middleware is the extent to which realistic testing occurs before release of the software into the production environment. We describe here an automated system for validating releases of the Open Science Grid software stack that leverages the (pilot-based) PanDA job management system developed and used by the ATLAS experiment. The system was motivated by a desire to subject the OSG Integration Testbed to more realistic validation tests. In particular those which resemble to every extent possible actual job workflows used by the experiments thus utilizing job scheduling at the compute element (CE), use of the worker node execution environment, transfer of data to/from the local storage element (SE), etc. The context is that candidate releases of OSG compute and storage elements can be tested by injecting large numbers of synthetic jobs varying in complexity and coverage of services tested. The native capabilities of the PanDA system can thus be used to define jobs, monitor their execution, and archive the resulting run statistics including success and failure modes. A repository of generic workflows and job types to measure various metrics of interest has been created. A command-line toolset has been developed so that testbed managers can quickly submit "VO-like" jobs into the system when newly deployed services are ready for testing. A system for automatic submission has been crafted to send jobs to integration testbed sites, collecting the results in a central service and generating regular reports for performance and reliability.

  5. Permanent Magnet Synchronous Condenser for Wind Power Plant Grid Connection Support: Preprint

    SciTech Connect

    Hsu, P.; Muljadi, E.

    2015-04-03

    A synchronous condenser (SC) using a permanent magnet synchronous generator (PMSG) is proposed for providing necessary reactive power to a wind power plant to support its connection to a weak grid. A PMSG has the advantage of higher efficiency and reliability. Because of its lack of a field winding, a PMSG is typically controlled by a full-power converter, which can be costly. In the proposed system, the reactive power of the SC is controlled by a serially connected compensator operating in a closed-loop configuration. The compensator also damps the PMSG's tendency to oscillate. The compensator's VA rating is only a fraction of the rating of the SC and the PMSG. In this initial investigation, the proposed scheme is shown to be effective by computer simulations.

  6. Integrating grid-based and topological maps for mobile robot navigation

    SciTech Connect

    Thrun, S.; Buecken, A.

    1996-12-31

    Research on mobile robot navigation has produced two major paradigms for mapping indoor environments: grid-based and topological. While grid-based methods produce accurate metric maps, their complexity often prohibits efficient planning and problem solving in large-scale indoor environments. Topological maps, on the other hand, can be used much more efficiently, yet accurate and consistent topological maps are considerably difficult to learn in large-scale environments. This paper describes an approach that integrates both paradigms: grid-based and topological. Grid-based maps are learned using artificial neural networks and Bayesian integration. Topological maps are generated on top of the grid-based maps, by partitioning the latter into coherent regions. By combining both paradigms-grid-based and topological, the approach presented here gains the best of both worlds: accuracy/consistency and efficiency. The paper gives results for autonomously operating a mobile robot equipped with sonar sensors in populated multi-room environments.

  7. Roots and Connections: A Culturally Integrated Approach to EAL Instruction

    ERIC Educational Resources Information Center

    Apedaile, Sarah; Whitelaw, Cheryl

    2012-01-01

    This article describes a culturally integrated approach to teaching English as an Additional Language (EAL) through Roots and Connections: A Culturally Integrated ESL Curriculum for Community Orientation in Alberta. This was developed by the Centre for Intercultural Education to integrate intercultural sensitivity into English-language…

  8. A grid-connected photovoltaic power conversion system with single-phase multilevel inverter

    SciTech Connect

    Beser, Ersoy; Arifoglu, Birol; Camur, Sabri; Beser, Esra Kandemir

    2010-12-15

    This paper presents a grid-connected photovoltaic (PV) power conversion system based on a single-phase multilevel inverter. The proposed system fundamentally consists of PV arrays and a single-phase multilevel inverter structure. First, configuration and structural parts of the PV assisted inverter system are introduced in detail. To produce reference output voltage waves, a simple switching strategy based on calculating switching angles is improved. By calculated switching angles, the reference signal is produced as a multilevel shaped output voltage wave. The control algorithm and operational principles of the proposed system are explained. Operating PV arrays in the same load condition is a considerable point; therefore a simulation study is performed to arrange the PV arrays. After determining the number and connection types of the PV arrays, the system is configured through the arrangement of the PV arrays. The validity of the proposed system is verified through simulations and experimental study. The results demonstrate that the system can achieve lower total harmonic distortion (THD) on the output voltage and load current, and it is capable of operating synchronous and transferring power values having different characteristic to the grid. Hence, it is suitable to use the proposed configuration as a PV power conversion system in various applications. (author)

  9. Decentralized Energy Management System for Networked Microgrids in Grid-connected and Islanded Modes

    SciTech Connect

    Wang, Zhaoyu; Chen, Bokan; Wang, Jianhui; Kim, Jinho

    2015-06-17

    This paper proposes a decentralized energy management system (EMS) for the coordinated operation of networked Microgirds (MGs) in a distribution system. In the grid-connected mode, the distribution network operator (DNO) and each MG are considered as distinct entities with individual objectives to minimize their own operation costs. It is assumed that both dispatchable and renewable energy source (RES)-based distributed generators (DGs) exist in the distribution network and the networked MGs. In order to coordinate the operation of all entities, we apply a decentralized bi-level algorithm to solve the problem with the first level to conduct negotiations among all entities and the second level to update the non-converging penalties. In the islanded mode, the objective of each MG is to maintain a reliable power supply to its customers. In order to take into account the uncertainties of DG outputs and load consumption, we formulate the problems as two-stage stochastic programs. The first stage is to determine base generation setpoints based on the forecasts and the second stage is to adjust the generation outputs based on the realized scenarios. Case studies of a distribution system with networked MGs demonstrate the effectiveness of the proposed methodology in both grid-connected and islanded modes.

  10. Three Course Connections: Integrated Event Design

    ERIC Educational Resources Information Center

    Johnson, Corey W.; Pate, Joseph A.

    2013-01-01

    Integrated Event Design (IED) capitalizes on three distinct courses to achieve a blended course delivery: Event Management, Research and Evaluation (for undergraduate students), and Experiential Education (for graduate students). Through the use of an event management company metaphor that fully integrates the diverse curricular concepts, course…

  11. Differential Evolution Based IDWNN Controller for Fault Ride-Through of Grid-Connected Doubly Fed Induction Wind Generators.

    PubMed

    Manonmani, N; Subbiah, V; Sivakumar, L

    2015-01-01

    The key objective of wind turbine development is to ensure that output power is continuously increased. It is authenticated that wind turbines (WTs) supply the necessary reactive power to the grid at the time of fault and after fault to aid the flowing grid voltage. At this juncture, this paper introduces a novel heuristic based controller module employing differential evolution and neural network architecture to improve the low-voltage ride-through rate of grid-connected wind turbines, which are connected along with doubly fed induction generators (DFIGs). The traditional crowbar-based systems were basically applied to secure the rotor-side converter during the occurrence of grid faults. This traditional controller is found not to satisfy the desired requirement, since DFIG during the connection of crowbar acts like a squirrel cage module and absorbs the reactive power from the grid. This limitation is taken care of in this paper by introducing heuristic controllers that remove the usage of crowbar and ensure that wind turbines supply necessary reactive power to the grid during faults. The controller is designed in this paper to enhance the DFIG converter during the grid fault and this controller takes care of the ride-through fault without employing any other hardware modules. The paper introduces a double wavelet neural network controller which is appropriately tuned employing differential evolution. To validate the proposed controller module, a case study of wind farm with 1.5 MW wind turbines connected to a 25 kV distribution system exporting power to a 120 kV grid through a 30 km 25 kV feeder is carried out by simulation.

  12. Differential Evolution Based IDWNN Controller for Fault Ride-Through of Grid-Connected Doubly Fed Induction Wind Generators

    PubMed Central

    Manonmani, N.; Subbiah, V.; Sivakumar, L.

    2015-01-01

    The key objective of wind turbine development is to ensure that output power is continuously increased. It is authenticated that wind turbines (WTs) supply the necessary reactive power to the grid at the time of fault and after fault to aid the flowing grid voltage. At this juncture, this paper introduces a novel heuristic based controller module employing differential evolution and neural network architecture to improve the low-voltage ride-through rate of grid-connected wind turbines, which are connected along with doubly fed induction generators (DFIGs). The traditional crowbar-based systems were basically applied to secure the rotor-side converter during the occurrence of grid faults. This traditional controller is found not to satisfy the desired requirement, since DFIG during the connection of crowbar acts like a squirrel cage module and absorbs the reactive power from the grid. This limitation is taken care of in this paper by introducing heuristic controllers that remove the usage of crowbar and ensure that wind turbines supply necessary reactive power to the grid during faults. The controller is designed in this paper to enhance the DFIG converter during the grid fault and this controller takes care of the ride-through fault without employing any other hardware modules. The paper introduces a double wavelet neural network controller which is appropriately tuned employing differential evolution. To validate the proposed controller module, a case study of wind farm with 1.5 MW wind turbines connected to a 25 kV distribution system exporting power to a 120 kV grid through a 30 km 25 kV feeder is carried out by simulation. PMID:26516636

  13. Differential Evolution Based IDWNN Controller for Fault Ride-Through of Grid-Connected Doubly Fed Induction Wind Generators.

    PubMed

    Manonmani, N; Subbiah, V; Sivakumar, L

    2015-01-01

    The key objective of wind turbine development is to ensure that output power is continuously increased. It is authenticated that wind turbines (WTs) supply the necessary reactive power to the grid at the time of fault and after fault to aid the flowing grid voltage. At this juncture, this paper introduces a novel heuristic based controller module employing differential evolution and neural network architecture to improve the low-voltage ride-through rate of grid-connected wind turbines, which are connected along with doubly fed induction generators (DFIGs). The traditional crowbar-based systems were basically applied to secure the rotor-side converter during the occurrence of grid faults. This traditional controller is found not to satisfy the desired requirement, since DFIG during the connection of crowbar acts like a squirrel cage module and absorbs the reactive power from the grid. This limitation is taken care of in this paper by introducing heuristic controllers that remove the usage of crowbar and ensure that wind turbines supply necessary reactive power to the grid during faults. The controller is designed in this paper to enhance the DFIG converter during the grid fault and this controller takes care of the ride-through fault without employing any other hardware modules. The paper introduces a double wavelet neural network controller which is appropriately tuned employing differential evolution. To validate the proposed controller module, a case study of wind farm with 1.5 MW wind turbines connected to a 25 kV distribution system exporting power to a 120 kV grid through a 30 km 25 kV feeder is carried out by simulation. PMID:26516636

  14. ISOGA: Integrated Services Optical Grid Architecture for Emerging E-Science Collaborative Applications

    SciTech Connect

    Oliver Yu

    2008-11-28

    This final report describes the accomplishments in the ISOGA (Integrated Services Optical Grid Architecture) project. ISOGA enables efficient deployment of existing and emerging collaborative grid applications with increasingly diverse multimedia communication requirements over a wide-area multi-domain optical network grid; and enables collaborative scientists with fast retrieval and seamless browsing of distributed scientific multimedia datasets over a wide-area optical network grid. The project focuses on research and development in the following areas: the polymorphic optical network control planes to enable multiple switching and communication services simultaneously; the intelligent optical grid user-network interface to enable user-centric network control and monitoring; and the seamless optical grid dataset browsing interface to enable fast retrieval of local/remote dataset for visualization and manipulation.

  15. Making Connections: Intentional Teaching for Integrative Learning

    ERIC Educational Resources Information Center

    Higgs, Bettie, Ed.; Kilcommins, Shane, Ed.; Ryan, Tony, Ed.

    2010-01-01

    In this volume the authors document examples of programmes/courses/activities that are designed intentionally to build students' capacity to be integrative thinkers and learners. In doing so they try to analyse and name the learning that is taking place, and so make it visible to the reader. The work is intended as a resource for all those…

  16. Study on model current predictive control method of PV grid- connected inverters systems with voltage sag

    NASA Astrophysics Data System (ADS)

    Jin, N.; Yang, F.; Shang, S. Y.; Tao, T.; Liu, J. S.

    2016-08-01

    According to the limitations of the LVRT technology of traditional photovoltaic inverter existed, this paper proposes a low voltage ride through (LVRT) control method based on model current predictive control (MCPC). This method can effectively improve the photovoltaic inverter output characteristics and response speed. The MCPC method of photovoltaic grid-connected inverter designed, the sum of the absolute value of the predictive current and the given current error is adopted as the cost function with the model predictive control method. According to the MCPC, the optimal space voltage vector is selected. Photovoltaic inverter has achieved automatically switches of priority active or reactive power control of two control modes according to the different operating states, which effectively improve the inverter capability of LVRT. The simulation and experimental results proves that the proposed method is correct and effective.

  17. Connecting Art, Learning, and Creativity: A Case for Curriculum Integration

    ERIC Educational Resources Information Center

    Marshall, Julia

    2005-01-01

    The author argues that "substantive" art integration harmonizes with contemporary postmodern thought in art education and represents a strategy for teaching art in a postmodern way. Bringing together theories from cognitive science and metaphor theory (specifically connection and projection), the author shows how substantive integration promotes…

  18. Accurate path integration in continuous attractor network models of grid cells.

    PubMed

    Burak, Yoram; Fiete, Ila R

    2009-02-01

    Grid cells in the rat entorhinal cortex display strikingly regular firing responses to the animal's position in 2-D space and have been hypothesized to form the neural substrate for dead-reckoning. However, errors accumulate rapidly when velocity inputs are integrated in existing models of grid cell activity. To produce grid-cell-like responses, these models would require frequent resets triggered by external sensory cues. Such inadequacies, shared by various models, cast doubt on the dead-reckoning potential of the grid cell system. Here we focus on the question of accurate path integration, specifically in continuous attractor models of grid cell activity. We show, in contrast to previous models, that continuous attractor models can generate regular triangular grid responses, based on inputs that encode only the rat's velocity and heading direction. We consider the role of the network boundary in the integration performance of the network and show that both periodic and aperiodic networks are capable of accurate path integration, despite important differences in their attractor manifolds. We quantify the rate at which errors in the velocity integration accumulate as a function of network size and intrinsic noise within the network. With a plausible range of parameters and the inclusion of spike variability, our model networks can accurately integrate velocity inputs over a maximum of approximately 10-100 meters and approximately 1-10 minutes. These findings form a proof-of-concept that continuous attractor dynamics may underlie velocity integration in the dorsolateral medial entorhinal cortex. The simulations also generate pertinent upper bounds on the accuracy of integration that may be achieved by continuous attractor dynamics in the grid cell network. We suggest experiments to test the continuous attractor model and differentiate it from models in which single cells establish their responses independently of each other. PMID:19229307

  19. PREFACE: Nonlinearity and Geometry: connections with integrability Nonlinearity and Geometry: connections with integrability

    NASA Astrophysics Data System (ADS)

    Cieslinski, Jan L.; Ferapontov, Eugene V.; Kitaev, Alexander V.; Nimmo, Jonathan J. C.

    2009-10-01

    -component dispersionless Boussinesq-type system. T E Kouloukas and V G Papageorgiou introduce a family of nonparametric Yang-Baxter maps obtained by re-factorization of matrix polynomials of first degree. These maps are Poisson with respect to the Sklyanin bracket, and their degenerations are connected to known integrable systems on quad-graphs. S V Manakov and P M Santini apply a novel version of the inverse scattering transform based on Lax pairs in multidimensional commuting vector fields to the heavenly and Pavlov equations, establishing that their localized solutions evolve without breaking, and constructing the long-time behaviour of the corresponding Cauchy problems. Discretizations of integrable geometric models depend heavily on the coordinates used. M Nieszporski and A Sym show how to discretize Bianchi surfaces (associated with an elliptic version of the Ernst equation) in arbitrary parametrization. C Rogers and A Szereszewski study the Bäcklund transformation for L-isothermic surfaces in the original Bianchi formulation. They establish a connection between this transformation and a nonhomogeneous linear Schrödinger equation and construct a class of generalized Dupin cyclides. W K Schief, A Szereszewski and C Rogers study a classical system of equilibrium equations for shell membranes. Various examples of viable membrane geometries lead to remarkable geometric configurations such as generalized Dupin cyclides and L-minimal surfaces. A Sergyeyev constructs infinite hierarchies of nonlocal higher symmetries for the oriented associativity equations using the spectral problem. The hierarchies in question generalize those constructed by Chen, Kontsevich and Schwarz for the WDVV equations. J Shiraishi and Y Tutiya study an integro-differential equation which generalizes the periodic intermediate long wave equation. The kernel of the singular integral involved is a second order difference of the Weierstrass ζ-function. Using Sato's formulation, the authors

  20. DISTRIBUTED GRID-CONNECTED PHOTOVOLTAIC POWER SYSTEM EMISSION OFFSET ASSESSMENT: STATISTICAL TEST OF SIMULATED- AND MEASURED-BASED DATA

    EPA Science Inventory

    This study assessed the pollutant emission offset potential of distributed grid-connected photovoltaic (PV) power systems. Computer-simulated performance results were utilized for 211 PV systems located across the U.S. The PV systems' monthly electrical energy outputs were based ...

  1. Implementation of high concentration photovoltaic grid connected power plant for training, research, innovation and solar electricity production

    NASA Astrophysics Data System (ADS)

    Barhdadi, A.; Benazzouz, A.; Fabrizio, B.; Verdilio, D.

    2015-04-01

    In this paper, performance monitoring program is applied to a grid-connected high concentration photovoltaic power plant in order to identify any operational problem and to make sure of its optimal and continuous power generation working conditions. A preventive maintenance plan was also established and proposed for the whole system.

  2. Integrity of Bolted Angle Connections Subjected to Simulated Column Removal

    PubMed Central

    Weigand, Jonathan M.; Berman, Jeffrey W.

    2016-01-01

    Large-scale tests of steel gravity framing systems (SGFSs) have shown that the connections are critical to the system integrity, when a column suffers damage that compromises its ability to carry gravity loads. When supporting columns were removed, the SGFSs redistributed gravity loads through the development of an alternate load path in a sustained tensile configuration resulting from large vertical deflections. The ability of the system to sustain such an alternate load path depends on the capacity of the gravity connections to remain intact after undergoing large rotation and axial extension demands, for which they were not designed. This study experimentally evaluates the performance of steel bolted angle connections subjected to loading consistent with an interior column removal. The characteristic connection behaviors are described and the performance of multiple connection configurations are compared in terms of their peak resistances and deformation capacities. PMID:27110059

  3. An infrastructure for the integration of geoscience instruments and sensors on the Grid

    NASA Astrophysics Data System (ADS)

    Pugliese, R.; Prica, M.; Kourousias, G.; Del Linz, A.; Curri, A.

    2009-04-01

    The Grid, as a computing paradigm, has long been in the attention of both academia and industry[1]. The distributed and expandable nature of its general architecture result to scalability and more efficient utilisation of the computing infrastructures. The scientific community, including that of geosciences, often handles problems with very high requirements in data processing, transferring, and storing[2,3]. This has raised the interest on Grid technologies but these are often viewed solely as an access gateway to HPC. Suitable Grid infrastructures could provide the geoscience community with additional benefits like those of sharing, remote access and control of scientific systems. These systems can be scientific instruments, sensors, robots, cameras and any other device used in geosciences. The solution for practical, general, and feasible Grid-enabling of such devices requires non-intrusive extensions on core parts of the current Grid architecture. We propose an extended version of an architecture[4] that can serve as the solution to the problem. The solution we propose is called Grid Instrument Element (IE) [5]. It is an addition to the existing core Grid parts; the Computing Element (CE) and the Storage Element (SE) that serve the purposes that their name suggests. The IE that we will be referring to, and the related technologies have been developed in the EU project on the Deployment of Remote Instrumentation Infrastructure (DORII1). In DORII, partners of various scientific communities including those of Earthquake, Environmental science, and Experimental science, have adopted the technology of the Instrument Element in order to integrate to the Grid their devices. The Oceanographic and coastal observation and modelling Mediterranean Ocean Observing Network (OGS2), a DORII partner, is in the process of deploying the above mentioned Grid technologies on two types of observational modules: Argo profiling floats and a novel Autonomous Underwater Vehicle (AUV

  4. Divergence preserving discrete surface integral methods for Maxwell's curl equations using non-orthogonal unstructured grids

    NASA Technical Reports Server (NTRS)

    Madsen, Niel K.

    1992-01-01

    Several new discrete surface integral (DSI) methods for solving Maxwell's equations in the time-domain are presented. These methods, which allow the use of general nonorthogonal mixed-polyhedral unstructured grids, are direct generalizations of the canonical staggered-grid finite difference method. These methods are conservative in that they locally preserve divergence or charge. Employing mixed polyhedral cells, (hexahedral, tetrahedral, etc.) these methods allow more accurate modeling of non-rectangular structures and objects because the traditional stair-stepped boundary approximations associated with the orthogonal grid based finite difference methods can be avoided. Numerical results demonstrating the accuracy of these new methods are presented.

  5. Integrating Clinical Trial Imaging Data Resources Using Service-Oriented Architecture and Grid Computing

    PubMed Central

    Cladé, Thierry; Snyder, Joshua C.

    2010-01-01

    Clinical trials which use imaging typically require data management and workflow integration across several parties. We identify opportunities for all parties involved to realize benefits with a modular interoperability model based on service-oriented architecture and grid computing principles. We discuss middleware products for implementation of this model, and propose caGrid as an ideal candidate due to its healthcare focus; free, open source license; and mature developer tools and support. PMID:20449775

  6. Grid Integration and the Carrying Capacity of the U.S. Grid to Incorporate Variable Renewable Energy

    SciTech Connect

    Cochran, Jaquelin; Denholm, Paul; Speer, Bethany; Miller, Mackay

    2015-04-23

    In the United States and elsewhere, renewable energy (RE) generation supplies an increasingly large percentage of annual demand, including nine U.S. states where wind comprised over 10% of in-state generation in 2013. This white paper summarizes the challenges to integrating increasing amounts of variable RE, identifies emerging practices in power system planning and operation that can facilitate grid integration, and proposes a unifying concept—economic carrying capacity—that can provide a framework for evaluating actions to accommodate higher penetrations of RE. There is growing recognition that while technical challenges to variable RE integration are real, they can generally be addressed via a variety of solutions that vary in implementation cost. As a result, limits to RE penetration are primarily economic, driven by factors that include transmission and the flexibility of the power grid to balance supply and demand. This limit can be expressed as economic carrying capacity, or the point at which variable RE is no longer economically competitive or desirable to the system or society.

  7. Grid-connected polymer solar panels: initial considerations of cost, lifetime, and practicality.

    PubMed

    Medford, Andrew J; Lilliedal, Mathilde R; Jørgensen, Mikkel; Aarø, Dennis; Pakalski, Heinz; Fyenbo, Jan; Krebs, Frederik C

    2010-09-13

    Large solar panels were constructed from polymer solar cell modules prepared using full roll-to-roll (R2R) manufacture based on the previously published ProcessOne. The individual flexible polymer solar modules comprising multiple serially connected single cell stripes were joined electrically and laminated between a 4 mm tempered glass window and black Tetlar foil using two sheets of 0.5 mm thick ethylene vinyl acetate (EVA). The panels produced up to 8 W with solar irradiance of ~960 Wm⁻², and had outer dimensions of 1 m x 1.7 m with active areas up to 9180 cm². Panels were mounted on a tracking station and their output was grid connected between testing. Several generations of polymer solar cells and panel constructions were tested in this context to optimize the production of polymer solar panels. Cells lacking a R2R barrier layer were found to degrade due to diffusion of oxygen after less than a month, while R2R encapsulated cells showed around 50% degradation after 6 months but suffered from poor performance due to de-lamination during panel production. A third generation of panels with various barrier layers was produced to optimize the choice of barrier foil and it was found that the inclusion of a thin protective foil between the cell and the barrier foil is critical. The findings provide a preliminary foundation for the production and optimization of large-area polymer solar panels and also enabled a cost analysis of solar panels based on polymer solar cells.

  8. Grid-connected polymer solar panels: initial considerations of cost, lifetime, and practicality.

    PubMed

    Medford, Andrew J; Lilliedal, Mathilde R; Jørgensen, Mikkel; Aarø, Dennis; Pakalski, Heinz; Fyenbo, Jan; Krebs, Frederik C

    2010-09-13

    Large solar panels were constructed from polymer solar cell modules prepared using full roll-to-roll (R2R) manufacture based on the previously published ProcessOne. The individual flexible polymer solar modules comprising multiple serially connected single cell stripes were joined electrically and laminated between a 4 mm tempered glass window and black Tetlar foil using two sheets of 0.5 mm thick ethylene vinyl acetate (EVA). The panels produced up to 8 W with solar irradiance of ~960 Wm⁻², and had outer dimensions of 1 m x 1.7 m with active areas up to 9180 cm². Panels were mounted on a tracking station and their output was grid connected between testing. Several generations of polymer solar cells and panel constructions were tested in this context to optimize the production of polymer solar panels. Cells lacking a R2R barrier layer were found to degrade due to diffusion of oxygen after less than a month, while R2R encapsulated cells showed around 50% degradation after 6 months but suffered from poor performance due to de-lamination during panel production. A third generation of panels with various barrier layers was produced to optimize the choice of barrier foil and it was found that the inclusion of a thin protective foil between the cell and the barrier foil is critical. The findings provide a preliminary foundation for the production and optimization of large-area polymer solar panels and also enabled a cost analysis of solar panels based on polymer solar cells. PMID:21165057

  9. Integration, Continuity and a Connection with Probability Density Functions

    ERIC Educational Resources Information Center

    Samuels, M.

    2006-01-01

    This note considers functions of two variables which are continuous on a possibly unbounded closed region in [vertical bar]R[squared], and the functions of one variable obtained by integrating out the other variable over this region. The question of continuity of these functions is investigated, as are connections with joint density and marginal…

  10. Connecting and Integrating Theoretical Frames: The TELMA Contribution

    ERIC Educational Resources Information Center

    Artigue, Michele; Cerulli, Michele; Haspekian, Mariam; Maracci, Mirko

    2009-01-01

    This paper presents the methodology developed within TELMA for connecting and integrating the theoretical frames used by the different teams for studying the design and use of interactive learning environments in mathematics education. Two case studies are then analysed and compared in order to illustrate the methodology and the results it can…

  11. Multiobjective Particle Swarm Optimization for the optimal design of photovoltaic grid-connected systems

    SciTech Connect

    Kornelakis, Aris

    2010-12-15

    Particle Swarm Optimization (PSO) is a highly efficient evolutionary optimization algorithm. In this paper a multiobjective optimization algorithm based on PSO applied to the optimal design of photovoltaic grid-connected systems (PVGCSs) is presented. The proposed methodology intends to suggest the optimal number of system devices and the optimal PV module installation details, such that the economic and environmental benefits achieved during the system's operational lifetime period are both maximized. The objective function describing the economic benefit of the proposed optimization process is the lifetime system's total net profit which is calculated according to the method of the Net Present Value (NPV). The second objective function, which corresponds to the environmental benefit, equals to the pollutant gas emissions avoided due to the use of the PVGCS. The optimization's decision variables are the optimal number of the PV modules, the PV modules optimal tilt angle, the optimal placement of the PV modules within the available installation area and the optimal distribution of the PV modules among the DC/AC converters. (author)

  12. Transaction-Based Controls for Building-Grid Integration: VOLTTRON™

    SciTech Connect

    Akyol, Bora A.; Haack, Jereme N.; Hernandez, George; Katipamula, Srinivas; Widergren, Steven E.

    2015-07-01

    The U.S. Department of Energy’s (DOE’s) Building Technologies Office (BTO) is supporting the development of a “transactional network” concept that supports energy, operational, and financial transactions between building systems (e.g., rooftop units -- RTUs), and the electric power grid using applications, or 'agents', that reside either on the equipment, on local building controllers, or in the Cloud. The transactional network vision is delivered using a real-time, scalable reference platform called VOLTTRON that supports the needs of the changing energy system. VOLTTRON is an agent execution and an innovative distributed control and sensing software platform that supports modern control strategies, including agent-based and transaction-based controls. It enables mobile and stationary software agents to perform information gathering, processing, and control actions.

  13. Optimal Dispatch of Unreliable Electric Grid-Connected Diesel Generator-Battery Power Systems

    NASA Astrophysics Data System (ADS)

    Xu, D.; Kang, L.

    2015-06-01

    Diesel generator (DG)-battery power systems are often adopted by telecom operators, especially in semi-urban and rural areas of developing countries. Unreliable electric grids (UEG), which have frequent and lengthy outages, are peculiar to these regions. DG-UEG-battery power system is an important kind of hybrid power system. System dispatch is one of the key factors to hybrid power system integration. In this paper, the system dispatch of a DG-UEG-lead acid battery power system is studied with the UEG of relatively ample electricity in Central African Republic (CAR) and UEG of poor electricity in Congo Republic (CR). The mathematical models of the power system and the UEG are studied for completing the system operation simulation program. The net present cost (NPC) of the power system is the main evaluation index. The state of charge (SOC) set points and battery bank charging current are the optimization variables. For the UEG in CAR, the optimal dispatch solution is SOC start and stop points 0.4 and 0.5 that belong to the Micro-Cycling strategy and charging current 0.1 C. For the UEG in CR, the optimal dispatch solution is of 0.1 and 0.8 that belongs to the Cycle-Charging strategy and 0.1 C. Charging current 0.1 C is suitable for both grid scenarios compared to 0.2 C. It makes the dispatch strategy design easier in commercial practices that there are a few very good candidate dispatch solutions with system NPC values close to that of the optimal solution for both UEG scenarios in CAR and CR.

  14. DICOMGrid: a middleware to integrate PACS and EELA-2 grid infrastructure

    NASA Astrophysics Data System (ADS)

    Moreno, Ramon A.; de Sá Rebelo, Marina; Gutierrez, Marco A.

    2010-03-01

    Medical images provide lots of information for physicians, but the huge amount of data produced by medical image equipments in a modern Health Institution is not completely explored in its full potential yet. Nowadays medical images are used in hospitals mostly as part of routine activities while its intrinsic value for research is underestimated. Medical images can be used for the development of new visualization techniques, new algorithms for patient care and new image processing techniques. These research areas usually require the use of huge volumes of data to obtain significant results, along with enormous computing capabilities. Such qualities are characteristics of grid computing systems such as EELA-2 infrastructure. The grid technologies allow the sharing of data in large scale in a safe and integrated environment and offer high computing capabilities. In this paper we describe the DicomGrid to store and retrieve medical images, properly anonymized, that can be used by researchers to test new processing techniques, using the computational power offered by grid technology. A prototype of the DicomGrid is under evaluation and permits the submission of jobs into the EELA-2 grid infrastructure while offering a simple interface that requires minimal understanding of the grid operation.

  15. Integration of HTS Cables in the Future Grid of the Netherlands

    NASA Astrophysics Data System (ADS)

    Zuijderduin, R.; Chevtchenko, O.; Smit, J. J.; Aanhaanen, G.; Melnik, I.; Geschiere, A.

    Due to increasing power demand, the electricity grid of the Netherlands is changing. The future transmission grid will obtain electrical power generated by decentralized renewable sources, together with large scale generation units located at the coastal region. In this way electrical power has to be distributed and transmitted over longer distances from generation to end user. Potential grid issues like: amount of distributed power, grid stability and electrical loss dissipation merit particular attention. High temperature superconductors (HTS) can play an important role in solving these grid problems. Advantages to integrate HTS components at transmission voltages are numerous: more transmittable power together with less emissions, intrinsic fault current limiting capability, lower ac loss, better control of power flow, reduced footprint, less magnetic field emissions, etc. The main obstacle at present is the relatively high price of HTS conductor. However as the price goes down, initial market penetration of several HTS components (e.g.: cables, fault current limiters) is expected by year 2015. In the full paper we present selected ways to integrate EHV AC HTS cables depending on a particular future grid scenario in the Netherlands.

  16. NREL Confirms Large Potential for Grid Integration of Wind, Solar Power (Fact Sheet)

    SciTech Connect

    Not Available

    2011-10-01

    To fully harvest the nation's bountiful wind and solar resources, it is critical to know how much electrical power from these renewable resources could be integrated reliably into the grid. To inform the discussion about the potential of such variable sources, the National Renewable Energy Laboratory (NREL) launched two key regional studies, examining the east and west sections of the U.S. power grid. The studies show that it is technically possible for U.S. power systems to integrate 20%-35% renewable electricity if infrastructure and operational improvements can be made.

  17. Reduction of a grid moire pattern by integrating a carbon-interspaced high precision x-ray grid with a digital radiographic detector

    SciTech Connect

    Yoon, Jai-Woong; Park, Young-Guk; Park, Chun-Joo; Kim, Do-Il; Lee, Jin-Ho; Chung, Nag-Kun; Choe, Bo-Young; Suh, Tae-Suk; Lee, Hyoung-Koo

    2007-11-15

    The stationary grid commonly used with a digital x-ray detector causes a moire interference pattern due to the inadequate sampling of the grid shadows by the detector pixels. There are limitations with the previous methods used to remove the moire such as imperfect electromagnetic interference shielding and the loss of image information. A new method is proposed for removing the moire pattern by integrating a carbon-interspaced high precision x-ray grid with high grid line uniformity with the detector for frequency matching. The grid was aligned to the detector by translating and rotating the x-ray grid with respect to the detector using microcontrolled alignment mechanism. The gap between the grid and the detector surface was adjusted with micrometer precision to precisely match the projected grid line pitch to the detector pixel pitch. Considering the magnification of the grid shadows on the detector plane, the grids were manufactured such that the grid line frequency was slightly higher than the detector sampling frequency. This study examined the factors that affect the moire pattern, particularly the line frequency and displacement. The frequency of the moire pattern was found to be sensitive to the angular displacement of the grid with respect to the detector while the horizontal translation alters the phase but not the moire frequency. The frequency of the moire pattern also decreased with decreasing difference in frequency between the grid and the detector, and a moire-free image was produced after complete matching for a given source to detector distance. The image quality factors including the contrast, signal-to-noise ratio and uniformity in the images with and without the moire pattern were investigated.

  18. Compatibility Study of Protective Relaying in a Grid-Connected Fuel Cell

    SciTech Connect

    Staunton, R.H.

    2004-04-15

    addressed other important and timely issues. For instance, the study includes an evaluation of the effectiveness of the fuel cell's synthesized relay protection scheme relative to the recently issued IEEE 1547 interconnection standard. Together, these activities should serve to reduce the number of unknowns pertaining to unconventional protective circuits, to the benefit of DG manufacturers, vendors, prospective and current users of DG, and electricity suppliers/distributors. Although more grid-connect fuel cell interruptions were encountered in this study than originally anticipated, and the investigation and findings became quite complex, every effort was made to clearly summarize the interconnection causes and issues throughout the report and especially in the summary found in Sect. 4. ORNL's funding of this study is sponsored equally by (1) the Department of Energy's (DOE's) Office of Distributed Energy Resources and (2) the Distributed Generation Technologies program of the Tennessee Valley Authority (TVA).

  19. Modeling and control of distributed energy systems during transition between grid connected and standalone modes

    NASA Astrophysics Data System (ADS)

    Arafat, Md Nayeem

    Distributed generation systems (DGs) have been penetrating into our energy networks with the advancement in the renewable energy sources and energy storage elements. These systems can operate in synchronism with the utility grid referred to as the grid connected (GC) mode of operation, or work independently, referred to as the standalone (SA) mode of operation. There is a need to ensure continuous power flow during transition between GC and SA modes, referred to as the transition mode, in operating DGs. In this dissertation, efficient and effective transition control algorithms are developed for DGs operating either independently or collectively with other units. Three techniques are proposed in this dissertation to manage the proper transition operations. In the first technique, a new control algorithm is proposed for an independent DG which can operate in SA and GC modes. The proposed transition control algorithm ensures low total harmonic distortion (THD) and less voltage fluctuation during mode transitions compared to the other techniques. In the second technique, a transition control is suggested for a collective of DGs operating in a microgrid system architecture to improve the reliability of the system, reduce the cost, and provide better performance. In this technique, one of the DGs in a microgrid system, referred to as a dispatch unit , takes the additional responsibility of mode transitioning to ensure smooth transition and supply/demand balance in the microgrid. In the third technique, an alternative transition technique is proposed through hybridizing the current and droop controllers. The proposed hybrid transition control technique has higher reliability compared to the dispatch unit concept. During the GC mode, the proposed hybrid controller uses current control. During the SA mode, the hybrid controller uses droop control. During the transition mode, both of the controllers participate in formulating the inverter output voltage but with different

  20. Integrating reconfigurable hardware-based grid for high performance computing.

    PubMed

    Dondo Gazzano, Julio; Sanchez Molina, Francisco; Rincon, Fernando; López, Juan Carlos

    2015-01-01

    FPGAs have shown several characteristics that make them very attractive for high performance computing (HPC). The impressive speed-up factors that they are able to achieve, the reduced power consumption, and the easiness and flexibility of the design process with fast iterations between consecutive versions are examples of benefits obtained with their use. However, there are still some difficulties when using reconfigurable platforms as accelerator that need to be addressed: the need of an in-depth application study to identify potential acceleration, the lack of tools for the deployment of computational problems in distributed hardware platforms, and the low portability of components, among others. This work proposes a complete grid infrastructure for distributed high performance computing based on dynamically reconfigurable FPGAs. Besides, a set of services designed to facilitate the application deployment is described. An example application and a comparison with other hardware and software implementations are shown. Experimental results show that the proposed architecture offers encouraging advantages for deployment of high performance distributed applications simplifying development process.

  1. Integrating reconfigurable hardware-based grid for high performance computing.

    PubMed

    Dondo Gazzano, Julio; Sanchez Molina, Francisco; Rincon, Fernando; López, Juan Carlos

    2015-01-01

    FPGAs have shown several characteristics that make them very attractive for high performance computing (HPC). The impressive speed-up factors that they are able to achieve, the reduced power consumption, and the easiness and flexibility of the design process with fast iterations between consecutive versions are examples of benefits obtained with their use. However, there are still some difficulties when using reconfigurable platforms as accelerator that need to be addressed: the need of an in-depth application study to identify potential acceleration, the lack of tools for the deployment of computational problems in distributed hardware platforms, and the low portability of components, among others. This work proposes a complete grid infrastructure for distributed high performance computing based on dynamically reconfigurable FPGAs. Besides, a set of services designed to facilitate the application deployment is described. An example application and a comparison with other hardware and software implementations are shown. Experimental results show that the proposed architecture offers encouraging advantages for deployment of high performance distributed applications simplifying development process. PMID:25874241

  2. Integrating Reconfigurable Hardware-Based Grid for High Performance Computing

    PubMed Central

    Dondo Gazzano, Julio; Sanchez Molina, Francisco; Rincon, Fernando; López, Juan Carlos

    2015-01-01

    FPGAs have shown several characteristics that make them very attractive for high performance computing (HPC). The impressive speed-up factors that they are able to achieve, the reduced power consumption, and the easiness and flexibility of the design process with fast iterations between consecutive versions are examples of benefits obtained with their use. However, there are still some difficulties when using reconfigurable platforms as accelerator that need to be addressed: the need of an in-depth application study to identify potential acceleration, the lack of tools for the deployment of computational problems in distributed hardware platforms, and the low portability of components, among others. This work proposes a complete grid infrastructure for distributed high performance computing based on dynamically reconfigurable FPGAs. Besides, a set of services designed to facilitate the application deployment is described. An example application and a comparison with other hardware and software implementations are shown. Experimental results show that the proposed architecture offers encouraging advantages for deployment of high performance distributed applications simplifying development process. PMID:25874241

  3. The Optimized Operation of Gas Turbine Combined Heat and Power Units Oriented for the Grid-Connected Control

    NASA Astrophysics Data System (ADS)

    Xia, Shu; Ge, Xiaolin

    2016-04-01

    In this study, according to various grid-connected demands, the optimization scheduling models of Combined Heat and Power (CHP) units are established with three scheduling modes, which are tracking the total generation scheduling mode, tracking steady output scheduling mode and tracking peaking curve scheduling mode. In order to reduce the solution difficulty, based on the principles of modern algebraic integers, linearizing techniques are developed to handle complex nonlinear constrains of the variable conditions, and the optimized operation problem of CHP units is converted into a mixed-integer linear programming problem. Finally, with specific examples, the 96 points day ahead, heat and power supply plans of the systems are optimized. The results show that, the proposed models and methods can develop appropriate coordination heat and power optimization programs according to different grid-connected control.

  4. A Stochastic Power Network Calculus for Integrating Renewable Energy Sources into the Power Grid

    SciTech Connect

    Wang, K; Ciucu, F; Lin, C; Low, SH

    2012-07-01

    Renewable energy such as solar and wind generation will constitute an important part of the future grid. As the availability of renewable sources may not match the load, energy storage is essential for grid stability. In this paper we investigate the feasibility of integrating solar photovoltaic (PV) panels and wind turbines into the grid by also accounting for energy storage. To deal with the fluctuation in both the power supply and demand, we extend and apply stochastic network calculus to analyze the power supply reliability with various renewable energy configurations. To illustrate the validity of the model, we conduct a case study for the integration of renewable energy sources into the power system of an island off the coast of Southern California. In particular, we asses the power supply reliability in terms of the average Fraction of Time that energy is Not-Served (FTNS).

  5. Connections beyond the margins of the power grid Information technology and the evolution of off-grid solar electricity in the developing world

    NASA Astrophysics Data System (ADS)

    Alstone, Peter Michael

    This work explores the intersections of information technology and off-grid electricity deployment in the developing world with focus on a key instance: the emergence of pay-as-you-go (PAYG) solar household-scale energy systems. It is grounded in detailed field study by my research team in Kenya between 2013-2014 that included primary data collection across the solar supply chain from global businesses through national and local distribution and to the end-users. We supplement the information with business process and national survey data to develop a detailed view of the markets, technology systems, and individuals who interact within those frameworks. The findings are presented in this dissertation as a series of four chapters with introductory, bridging, and synthesis material between them. The first chapter, Decentralized Energy Systems for Clean Electricity Access, presents a global view of the emerging off-grid power sector. Long-run trends in technology create "a unique moment in history" for closing the gap between global population and access to electricity, which has stubbornly held at 1-2 billion people without power since the initiation of the electric utility business model in the late 1800's. We show the potential for widespread near-term adoption of off-grid solar, which could lead to ten times less inequality in access and also ten times lower household-level climate impacts. Decentralized power systems that replace fuel-based incumbent lighting can advance the causes of climate stabilization, economic and social freedom and human health. Chapters two and three are focused on market and institutional dynamics present circa 2014 in for off-grid solar with a focus on the Kenya market. Chapter 2, "Off-grid Power and Connectivity", presents our findings related to the widespread influence of information technology across the supply chain for solar and in PAYG approaches. Using digital financing and embedded payment verification technology, PAYG

  6. A 50 kilowatt distributed grid-connected photovoltaic generation system for the University of Wyoming

    SciTech Connect

    Chowdhury, B.H.; Muknahallipatna, S.; Cupal, J.J.; Hamann, J.C.; Dinwoodie, T.; Shugar, D.

    1997-12-31

    The University of Wyoming (UW) campus is serving as the site for a 50 kilowatt solar photovoltaic (PV) system. Three sub-systems were sited and built on the UW campus in 1996. The first sub-system, a 10 kW roof-integrated system of PV roof tiles is located on the roof of the Engineering building. The second sub-system--a 5 kW rack-mounted, ballasted PV system is on a walkway roof of the Engineering building. The third sub-system is a 35 kW shade structure system and located adjacent to the parking lot of the university`s football stadium. The three sub-systems differ in their design strategy since each is being used for research and education at the university. Each sub-system, being located at some distance away from one another, supplies a different part of the campus grid. Efforts continue at setting up a central monitoring system which will receive data remotely from all locations. A part of this monitoring system is complete. While the initial monitoring data shows satisfactory performance, a number of reliability problems with PV modules and inverters have delayed full functionality of the system.

  7. Feasibility Study of Residential Grid-Connected Solar Photovoltaic Systems in the State of Indiana

    NASA Astrophysics Data System (ADS)

    Al-Odeh, Mahmoud

    This study aims to measure the financial viability of installing and using a residential grid-connected PV system in the State of Indiana while predicting its performance in eighteen geographical locations within the state over the system's expected lifetime. The null hypothesis of the study is that installing a PV system for a single family residence in the State of Indiana will not pay for itself within 25 years. Using a systematic approach consisting of six steps, data regarding the use of renewable energy in the State of Indiana was collected from the website of the US Department of Energy to perform feasibility analysis of the installation and use of a standard-sized residential PV system. The researcher was not able to reject the null hypothesis that installing a PV system for a single family residence in the State of Indiana will not pay for itself within 25 years. This study found that the standard PV system does not produce a positive project balance and does not pay for itself within 25 years (the life time of the system) assuming the average cost of a system. The government incentive programs are not enough to offset the cost of installing the system against the cost of the electricity that would not be purchased from the utility company. It can be concluded that the cost of solar PV is higher than the market valuation of the power it produces; thus, solar PV did not compete on the cost basis with the traditional competitive energy sources. Reducing the capital cost will make the standard PV system economically viable in Indiana. The study found that the capital cost for the system should be reduced by 15% - 56%.

  8. On computations of the integrated space shuttle flowfield using overset grids

    NASA Technical Reports Server (NTRS)

    Chiu, I-T.; Pletcher, R. H.; Steger, J. L.

    1990-01-01

    Numerical simulations using the thin-layer Navier-Stokes equations and chimera (overset) grid approach were carried out for flows around the integrated space shuttle vehicle over a range of Mach numbers. Body-conforming grids were used for all the component grids. Testcases include a three-component overset grid - the external tank (ET), the solid rocket booster (SRB) and the orbiter (ORB), and a five-component overset grid - the ET, SRB, ORB, forward and aft attach hardware, configurations. The results were compared with the wind tunnel and flight data. In addition, a Poisson solution procedure (a special case of the vorticity-velocity formulation) using primitive variables was developed to solve three-dimensional, irrotational, inviscid flows for single as well as overset grids. The solutions were validated by comparisons with other analytical or numerical solution, and/or experimental results for various geometries. The Poisson solution was also used as an initial guess for the thin-layer Navier-Stokes solution procedure to improve the efficiency of the numerical flow simulations. It was found that this approach resulted in roughly a 30 percent CPU time savings as compared with the procedure solving the thin-layer Navier-Stokes equations from a uniform free stream flowfield.

  9. Semi-implicit Integration Factor Methods on Sparse Grids for High-Dimensional Systems

    PubMed Central

    Wang, Dongyong; Chen, Weitao; Nie, Qing

    2015-01-01

    Numerical methods for partial differential equations in high-dimensional spaces are often limited by the curse of dimensionality. Though the sparse grid technique, based on a one-dimensional hierarchical basis through tensor products, is popular for handling challenges such as those associated with spatial discretization, the stability conditions on time step size due to temporal discretization, such as those associated with high-order derivatives in space and stiff reactions, remain. Here, we incorporate the sparse grids with the implicit integration factor method (IIF) that is advantageous in terms of stability conditions for systems containing stiff reactions and diffusions. We combine IIF, in which the reaction is treated implicitly and the diffusion is treated explicitly and exactly, with various sparse grid techniques based on the finite element and finite difference methods and a multi-level combination approach. The overall method is found to be efficient in terms of both storage and computational time for solving a wide range of PDEs in high dimensions. In particular, the IIF with the sparse grid combination technique is flexible and effective in solving systems that may include cross-derivatives and non-constant diffusion coefficients. Extensive numerical simulations in both linear and nonlinear systems in high dimensions, along with applications of diffusive logistic equations and Fokker-Planck equations, demonstrate the accuracy, efficiency, and robustness of the new methods, indicating potential broad applications of the sparse grid-based integration factor method. PMID:25897178

  10. Evaluating the performance of a 50 kilowatt grid-connected photovoltaic system

    SciTech Connect

    Chowdhury, B.H.; Muknahallipatn, S.; Cupal, J.J.; Hamann, J.C.

    1998-07-01

    A 50-kilowatt solar photovoltaic (PV) system was built at the University of Wyoming (UW) in 1996. The system comprises of three sub-systems. The first sub-system, a 10 kW roof-integrated system is located on the roof of the Engineering Building. The second sub-system is a 5 kW rack-mounted, ballasted PV system located on another part of the roof. The third sub-system is a 35 kW shade structure and is located adjacent to the university's football stadium. The three sub-systems differ in their design strategy since each is being used for research and education at the university. Each sub-system, being located at some distance away from one another, supplies a different part of the campus grid. Efforts are continuing for setting up a central monitoring system, which will receive data remotely from all locations. A part of this monitoring system is complete. The system as configured provides a great deal of flexibility, which is in turn demanded by the variety of signal types measured at each installation. Each installation requires measurement of multiple dc and ac voltages and currents and one slowly varying voltage (proportional to solar insolation). The simultaneous sampling, fast sample rate, and lowpass signal conditioning allow for accurate measurement of power factor and total harmonic distortion of the inverter outputs. Panel and inverter efficiencies can be determined via simultaneous DC and AC measurements. These performance monitors provide the essential data for characterization of the PV effect at the grid input, and enable the use of intelligent power factor correction and harmonic filtering. Monitoring of the system shows that the total harmonic distortion present in the ac power output is at or below the acceptable limit as recommended by IEEE 519-1992. The harmonic distortion worsens when the ac power reaches more than 3.8 kW. A number of reliability problems with PV modules and inverters have delayed full functionality of the system.

  11. Integrated Design Engineering Analysis (IDEA) Environment Automated Generation of Structured CFD Grids using Topology Methods

    NASA Technical Reports Server (NTRS)

    Kamhawi, Hilmi N.

    2012-01-01

    This report documents the work performed from March 2010 to March 2012. The Integrated Design and Engineering Analysis (IDEA) environment is a collaborative environment based on an object-oriented, multidisciplinary, distributed framework using the Adaptive Modeling Language (AML) as a framework and supporting the configuration design and parametric CFD grid generation. This report will focus on describing the work in the area of parametric CFD grid generation using novel concepts for defining the interaction between the mesh topology and the geometry in such a way as to separate the mesh topology from the geometric topology while maintaining the link between the mesh topology and the actual geometry.

  12. Connecting multiple spatial scales to decode the population activity of grid cells.

    PubMed

    Stemmler, Martin; Mathis, Alexander; Herz, Andreas V M

    2015-12-01

    Mammalian grid cells fire when an animal crosses the points of an imaginary hexagonal grid tessellating the environment. We show how animals can navigate by reading out a simple population vector of grid cell activity across multiple spatial scales, even though neural activity is intrinsically stochastic. This theory of dead reckoning explains why grid cells are organized into discrete modules within which all cells have the same lattice scale and orientation. The lattice scale changes from module to module and should form a geometric progression with a scale ratio of around 3/2 to minimize the risk of making large-scale errors in spatial localization. Such errors should also occur if intermediate-scale modules are silenced, whereas knocking out the module at the smallest scale will only affect spatial precision. For goal-directed navigation, the allocentric grid cell representation can be readily transformed into the egocentric goal coordinates needed for planning movements. The goal location is set by nonlinear gain fields that act on goal vector cells. This theory predicts neural and behavioral correlates of grid cell readout that transcend the known link between grid cells of the medial entorhinal cortex and place cells of the hippocampus. PMID:26824061

  13. Quantifying the Digital Divide: A Scientific Overview of Network Connectivity and Grid Infrastructure in South Asian Countries

    SciTech Connect

    Khan, Shahryar Muhammad; Cottrell, R.Les; Kalim, Umar; Ali, Arshad; /NUST, Rawalpindi

    2007-10-30

    The future of Computing in High Energy Physics (HEP) applications depends on both the Network and Grid infrastructure. South Asian countries such as India and Pakistan are making significant progress by building clusters as well as improving their network infrastructure However to facilitate the use of these resources, they need to manage the issues of network connectivity to be among the leading participants in Computing for HEP experiments. In this paper we classify the connectivity for academic and research institutions of South Asia. The quantitative measurements are carried out using the PingER methodology; an approach that induces minimal ICMP traffic to gather active end-to-end network statistics. The PingER project has been measuring the Internet performance for the last decade. Currently the measurement infrastructure comprises of over 700 hosts in more than 130 countries which collectively represents approximately 99% of the world's Internet-connected population. Thus, we are well positioned to characterize the world's connectivity. Here we present the current state of the National Research and Educational Networks (NRENs) and Grid Infrastructure in the South Asian countries and identify the areas of concern. We also present comparisons between South Asia and other developing as well as developed regions. We show that there is a strong correlation between the Network performance and several Human Development indices.

  14. Quantifying the digital divide: a scientific overview of network connectivity and grid infrastructure in South Asian countries

    NASA Astrophysics Data System (ADS)

    Khan, S. M.; Cottrell, R. L.; Kalim, U.; Ali, A.

    2008-07-01

    The future of Computing in High Energy Physics (HEP) applications depends on both the Network and Grid infrastructure. South Asian countries such as India and Pakistan are making significant progress by building clusters as well as improving their network infrastructure However to facilitate the use of these resources, they need to manage the issues of network connectivity to be among the leading participants in Computing for HEP experiments. In this paper we classify the connectivity for academic and research institutions of South Asia. The quantitative measurements are carried out using the PingER methodology; an approach that induces minimal ICMP traffic to gather active end-to-end network statistics. The PingER project has been measuring the Internet performance for the last decade. Currently the measurement infrastructure comprises of over 700 hosts in more than 130 countries which collectively represents approximately 99% of the world's Internet-connected population. Thus, we are well positioned to characterize the world's connectivity. Here we present the current state of the National Research and Educational Networks (NRENs) and Grid Infrastructure in the South Asian countries and identify the areas of concern. We also present comparisons between South Asia and other developing as well as developed regions. We show that there is a strong correlation between the Network performance and several Human Development indices.

  15. PREFACE: Nonlinearity and Geometry: connections with integrability Nonlinearity and Geometry: connections with integrability

    NASA Astrophysics Data System (ADS)

    Cieslinski, Jan L.; Ferapontov, Eugene V.; Kitaev, Alexander V.; Nimmo, Jonathan J. C.

    2009-10-01

    Geometric ideas are present in many areas of modern theoretical physics and they are usually associated with the presence of nonlinear phenomena. Integrable nonlinear systems play a prime role both in geometry itself and in nonlinear physics. One can mention general relativity, exact solutions of the Einstein equations, string theory, Yang-Mills theory, instantons, solitons in nonlinear optics and hydrodynamics, vortex dynamics, solvable models of statistical physics, deformation quantization, and many others. Soliton theory now forms a beautiful part of mathematics with very strong physical motivations and numerous applications. Interactions between mathematics and physics associated with integrability issues are very fruitful and stimulating. For instance, spectral theories of linear quantum mechanics turned out to be crucial for studying nonlinear integrable systems. The modern theory of integrable nonlinear partial differential and difference equations, or the `theory of solitons', is deeply rooted in the achievements of outstanding geometers of the end of the 19th and the beginning of the 20th century, such as Luigi Bianchi (1856-1928) and Jean Gaston Darboux (1842-1917). Transformations of surfaces and explicit constructions developed by `old' geometers were often rediscovered or reinterpreted in a modern framework. The great progress of recent years in so-called discrete geometry is certainly due to strong integrable motivations. A very remarkable feature of the results of the classical integrable geometry is the quite natural (although nontrivial) possibility of their discretization. This special issue is dedicated to Jean Gaston Darboux and his pioneering role in the development of the geometric ideas of modern soliton theory. The most famous aspects of his work are probably Darboux transformations and triply orthogonal systems of surfaces, whose role in modern mathematical physics cannot be overestimated. Indeed, Darboux transformations play a central

  16. Microcoil Spring Interconnects for Ceramic Grid Array Integrated Circuits

    NASA Technical Reports Server (NTRS)

    Strickland, S. M.; Hester, J. D.; Gowan, A. K.; Montgomery, R. K.; Geist, D. L.; Blanche, J. F.; McGuire, G. D.; Nash, T. S.

    2011-01-01

    As integrated circuit miniaturization trends continue, they drive the need for smaller higher input/output (I/O) packages. Hermetically sealed ceramic area array parts are the package of choice by the space community for high reliability space flight electronic hardware. Unfortunately, the coefficient of thermal expansion mismatch between the ceramic area array package and the epoxy glass printed wiring board limits the life of the interconnecting solder joint. This work presents the results of an investigation by Marshall Space Flight Center into a method to increase the life of this second level interconnection by the use of compliant microcoil springs. The design of the spring and its attachment process are presented along with thermal cycling results of microcoil springs (MCS) compared with state-of-the-art ball and column interconnections. Vibration testing has been conducted on MCS and high lead column parts. Radio frequency simulation and measurements have been made and the MCS has been modeled and a stress analysis performed. Thermal cycling and vibration testing have shown MCS interconnects to be significantly more reliable than solder columns. Also, MCS interconnects are less prone to handling damage than solder columns. Future work that includes shock testing, incorporation into a digital signal processor board, and process evaluation of expansion from a 400 I/O device to a device with over 1,100 I/O is identified.

  17. Impact of language on functional connectivity for audiovisual speech integration.

    PubMed

    Shinozaki, Jun; Hiroe, Nobuo; Sato, Masa-Aki; Nagamine, Takashi; Sekiyama, Kaoru

    2016-01-01

    Visual information about lip and facial movements plays a role in audiovisual (AV) speech perception. Although this has been widely confirmed, previous behavioural studies have shown interlanguage differences, that is, native Japanese speakers do not integrate auditory and visual speech as closely as native English speakers. To elucidate the neural basis of such interlanguage differences, 22 native English speakers and 24 native Japanese speakers were examined in behavioural or functional Magnetic Resonance Imaging (fMRI) experiments while mono-syllabic speech was presented under AV, auditory-only, or visual-only conditions for speech identification. Behavioural results indicated that the English speakers identified visual speech more quickly than the Japanese speakers, and that the temporal facilitation effect of congruent visual speech was significant in the English speakers but not in the Japanese speakers. Using fMRI data, we examined the functional connectivity among brain regions important for auditory-visual interplay. The results indicated that the English speakers had significantly stronger connectivity between the visual motion area MT and the Heschl's gyrus compared with the Japanese speakers, which may subserve lower-level visual influences on speech perception in English speakers in a multisensory environment. These results suggested that linguistic experience strongly affects neural connectivity involved in AV speech integration. PMID:27510407

  18. Impact of language on functional connectivity for audiovisual speech integration

    PubMed Central

    Shinozaki, Jun; Hiroe, Nobuo; Sato, Masa-aki; Nagamine, Takashi; Sekiyama, Kaoru

    2016-01-01

    Visual information about lip and facial movements plays a role in audiovisual (AV) speech perception. Although this has been widely confirmed, previous behavioural studies have shown interlanguage differences, that is, native Japanese speakers do not integrate auditory and visual speech as closely as native English speakers. To elucidate the neural basis of such interlanguage differences, 22 native English speakers and 24 native Japanese speakers were examined in behavioural or functional Magnetic Resonance Imaging (fMRI) experiments while mono-syllabic speech was presented under AV, auditory-only, or visual-only conditions for speech identification. Behavioural results indicated that the English speakers identified visual speech more quickly than the Japanese speakers, and that the temporal facilitation effect of congruent visual speech was significant in the English speakers but not in the Japanese speakers. Using fMRI data, we examined the functional connectivity among brain regions important for auditory-visual interplay. The results indicated that the English speakers had significantly stronger connectivity between the visual motion area MT and the Heschl’s gyrus compared with the Japanese speakers, which may subserve lower-level visual influences on speech perception in English speakers in a multisensory environment. These results suggested that linguistic experience strongly affects neural connectivity involved in AV speech integration. PMID:27510407

  19. Improved direct torque control of an induction generator used in a wind conversion system connected to the grid.

    PubMed

    Abdelli, Radia; Rekioua, Djamila; Rekioua, Toufik; Tounzi, Abdelmounaïm

    2013-07-01

    This paper presents a modulated hysteresis direct torque control (MHDTC) applied to an induction generator (IG) used in wind energy conversion systems (WECs) connected to the electrical grid through a back-to-back converter. The principle of this strategy consists in superposing to the torque reference a triangular signal, as in the PWM strategy, with the desired switching frequency. This new modulated reference is compared to the estimated torque by using a hysteresis controller as in the classical direct torque control (DTC). The aim of this new approach is to lead to a constant frequency and low THD in grid current with a unit power factor and a minimum voltage variation despite the wind variation. To highlight the effectiveness of the proposed method, a comparison was made with classical DTC and field oriented control method (FOC). The obtained simulation results, with a variable wind profile, show an adequate dynamic of the conversion system using the proposed method compared to the classical approaches.

  20. Digital signature embedding (DSE) for medical image integrity in a data grid off-site backup archive

    NASA Astrophysics Data System (ADS)

    Zhou, Zheng; Huang, H. K.; Liu, Brent J.

    2005-04-01

    One of the new trends to protect the PACS image data against disaster situations is to store clinical images at an off-site backup archive. In order to support the mission-critical clinical PACS, the backup archive must be 24/7 continuously available (CA). We have developed a novel Data Grid for this purpose using the grid computing technology. With the federation of several PAC systems in a grid, the Data Grid can provide the true CA (99.999%) backup for the PAC systems. However, image integrity becomes a new critical issue to the Data Grid where the image data are not under the protection of local PACS anymore. In this paper, we presented a digital signature embedding (DSE) method, which can assure image integrity in image transmission or archive. The DSE method permanently embeds the digital signature (DS) of the image in the image pixels using lossless data embedding approaches, which can completely recover the original image whenever desired. The permanently embedded DS in the image would provide the integrity assurance for medical image during its lifetime. The embedding process can be utilized by the local PACS archive server to embed the DS in every image before it is sent to the Data Grid. The embedded DS can then be extracted for verification to ensure image integrity when images arrived in the Data Grid or when images were retrieved back. Therefore, with the DSE method, we have extended our protection of image integrity from local PACS to the backup Data Grid.

  1. Large-scale wind power integration in Norway and impact on damping in the Nordic grid

    NASA Astrophysics Data System (ADS)

    Hagstrøm, Espen; Norheim, Ian; Uhlen, Kjetil

    2005-07-01

    The Nordic energy market is in need of new power generation capacity. Norway is today in shortage of electrical energy, and the hydropower-based system must rely on importing electrical power from its neighbours in a normal year of hydro inflow. One solution to this problem is to invest in new generation capacity, e.g. by integrating more wind power into the Norwegian grid. The Norwegian government has announced that 1000 MW of wind power will be installed in Norway by 2010, corresponding to an eventual energy production of approximately 3 TWh year-1. This article investigates the impact of wind power integration in Norway on the damping of interarea mode oscillations in the Nordic grid. The impact on the interarea mode oscillations is tested for various types of generators. Results from computer analyses of a simplified yet realistic equivalent of the Nordic power system are used to compute the interarea mode oscillations. Copyright

  2. Semi-Lagrangian integration of a grid-point shallow water model on the sphere

    NASA Technical Reports Server (NTRS)

    Mcdonald, A.; Bates, J. R.

    1988-01-01

    This paper describes a semi-Lagrangian technique for integrating the equations of motion on the global domain. The technique uses an auxiliary spherical coordinate system at each near-polar gridpoint of the latitude-longitude grid; the auxiliary system is obtained by a rotation such that the new equator passes through the gridpoint in question and the new coordinate directions coincide with those of the original system at that point. The technique was applied to the shallow water equations, incorporating a semiimplicit treatment of the adjustment terms on a C-grid, with two-time levels. A five day integration was successfully carried out for a situation involving strong cross-polar flow. No filtering or diffusion was required to maintain stability over a five day period.

  3. Exact Integrations of Polynomials and Symmetric Quadrature Formulas over Arbitrary Polyhedral Grids

    NASA Technical Reports Server (NTRS)

    Liu, Yen; Vinokur, Marcel

    1997-01-01

    This paper is concerned with two important elements in the high-order accurate spatial discretization of finite volume equations over arbitrary grids. One element is the integration of basis functions over arbitrary domains, which is used in expressing various spatial integrals in terms of discrete unknowns. The other consists of quadrature approximations to those integrals. Only polynomial basis functions applied to polyhedral and polygonal grids are treated here. Non-triangular polygonal faces are subdivided into a union of planar triangular facets, and the resulting triangulated polyhedron is subdivided into a union of tetrahedra. The straight line segment, triangle, and tetrahedron are thus the fundamental shapes that are the building blocks for all integrations and quadrature approximations. Integrals of products up to the fifth order are derived in a unified manner for the three fundamental shapes in terms of the position vectors of vertices. Results are given both in terms of tensor products and products of Cartesian coordinates. The exact polynomial integrals are used to obtain symmetric quadrature approximations of any degree of precision up to five for arbitrary integrals over the three fundamental domains. Using a coordinate-free formulation, simple and rational procedures are developed to derive virtually all quadrature formulas, including some previously unpublished. Four symmetry groups of quadrature points are introduced to derive Gauss formulas, while their limiting forms are used to derive Lobatto formulas. Representative Gauss and Lobatto formulas are tabulated. The relative efficiency of their application to polyhedral and polygonal grids is detailed. The extension to higher degrees of precision is discussed.

  4. SchizConnect: Virtual Data Integration in Neuroimaging

    PubMed Central

    Ambite, Jose Luis; Tallis, Marcelo; Alpert, Kathryn; Keator, David B.; King, Margaret; Landis, Drew; Konstantinidis, George; Calhoun, Vince D.; Potkin, Steven G.; Turner, Jessica A.; Wang, Lei

    2015-01-01

    In many scientific domains, including neuroimaging studies, there is a need to obtain increasingly larger cohorts to achieve the desired statistical power for discovery. However, the economics of imaging studies make it unlikely that any single study or consortia can achieve the desired sample sizes. What is needed is an architecture that can easily incorporate additional studies as they become available. We present such architecture based on a virtual data integration approach, where data remains at the original sources, and is retrieved and harmonized in response to user queries. This is in contrast to approaches that move the data to a central warehouse. We implemented our approach in the SchizConnect system that integrates data from three neuroimaging consortia on Schizophrenia: FBIRN's Human Imaging Database (HID), MRN's Collaborative Imaging and Neuroinformatics System (COINS), and the NUSDAST project at XNAT Central. A portal providing harmonized access to these sources is publicly deployed at schizconnect.org. PMID:26688837

  5. Separator-Integrated, Reversely Connectable Symmetric Lithium-Ion Battery.

    PubMed

    Wang, Yuhang; Zeng, Jiren; Cui, Xiaoqi; Zhang, Lijuan; Zheng, Gengfeng

    2016-02-24

    A separator-integrated, reversely connectable, symmetric lithium-ion battery is developed based on carbon-coated Li3V2(PO4)3 nanoparticles and polyvinylidene fluoride-treated separators. The Li3V2(PO4)3 nanoparticles are synthesized via a facile solution route followed by calcination in Ar/H2 atmosphere. Sucrose solution is used as the carbon source for uniform carbon coating on the Li3V2(PO4)3 nanoparticles. Both the carbon and the polyvinylidene fluoride treatments substantially improve the cycling life of the symmetric battery by preventing the dissolution and shuttle of the electroactive Li3V2(PO4)3. The obtained symmetric full cell exhibits a reversible capacity of ≈ 87 mA h g(-1), good cycling stability, and capacity retention of ≈ 70% after 70 cycles. In addition, this type of symmetric full cell can be operated in both forward and reverse connection modes, without any influence on the cycling of the battery. Furthermore, a new separator integration approach is demonstrated, which enables the direct deposition of electroactive materials for the battery assembly and does not affect the electrochemical performance. A 10-tandem-cell battery assembled without differentiating the electrode polarity exhibits a low thickness of ≈ 4.8 mm and a high output voltage of 20.8 V.

  6. Neighborhood Integration and Connectivity Predict Cognitive Performance and Decline

    PubMed Central

    Watts, Amber; Ferdous, Farhana; Moore, Keith Diaz; Burns, Jeffrey M.

    2015-01-01

    Objective Neighborhood characteristics may be important for promoting walking, but little research has focused on older adults, especially those with cognitive impairment. We evaluated the role of neighborhood characteristics on cognitive function and decline over a 2-year period adjusting for measures of walking. Method In a study of 64 older adults with and without mild Alzheimer's disease (AD), we evaluated neighborhood integration and connectivity using geographical information systems data and space syntax analysis. In multiple regression analyses, we used these characteristics to predict 2-year declines in factor analytically derived cognitive scores (attention, verbal memory, mental status) adjusting for age, sex, education, and self-reported walking. Results Neighborhood integration and connectivity predicted cognitive performance at baseline, and changes in cognitive performance over 2 years. The relationships between neighborhood characteristics and cognitive performance were not fully explained by self-reported walking. Discussion Clearer definitions of specific neighborhood characteristics associated with walkability are needed to better understand the mechanisms by which neighborhoods may impact cognitive outcomes. These results have implications for measuring neighborhood characteristics, design and maintenance of living spaces, and interventions to increase walking among older adults. We offer suggestions for future research measuring neighborhood characteristics and cognitive function. PMID:26504889

  7. SunEdison Photovoltaic Grid Integration Evaluation: Cooperative Research and Development Final Report, CRADA Number CRD-08-302

    SciTech Connect

    Kroposki, B.

    2012-09-01

    Under this Agreement, NREL will work with SunEdison to monitor and analyze the performance of photovoltaic (PV) systems as they relate to grid integration. Initially this project will examine the performance of PV systems with respect to evaluating the benefits and impacts on the electric power grid.

  8. Grid integration and smart grid implementation of emerging technologies in electric power systems through approximate dynamic programming

    NASA Astrophysics Data System (ADS)

    Xiao, Jingjie

    A key hurdle for implementing real-time pricing of electricity is a lack of consumers' responses. Solutions to overcome the hurdle include the energy management system that automatically optimizes household appliance usage such as plug-in hybrid electric vehicle charging (and discharging with vehicle-to-grid) via a two-way communication with the grid. Real-time pricing, combined with household automation devices, has a potential to accommodate an increasing penetration of plug-in hybrid electric vehicles. In addition, the intelligent energy controller on the consumer-side can help increase the utilization rate of the intermittent renewable resource, as the demand can be managed to match the output profile of renewables, thus making the intermittent resource such as wind and solar more economically competitive in the long run. One of the main goals of this dissertation is to present how real-time retail pricing, aided by control automation devices, can be integrated into the wholesale electricity market under various uncertainties through approximate dynamic programming. What distinguishes this study from the existing work in the literature is that whole- sale electricity prices are endogenously determined as we solve a system operator's economic dispatch problem on an hourly basis over the entire optimization horizon. This modeling and algorithm framework will allow a feedback loop between electricity prices and electricity consumption to be fully captured. While we are interested in a near-optimal solution using approximate dynamic programming; deterministic linear programming benchmarks are use to demonstrate the quality of our solutions. The other goal of the dissertation is to use this framework to provide numerical evidence to the debate on whether real-time pricing is superior than the current flat rate structure in terms of both economic and environmental impacts. For this purpose, the modeling and algorithm framework is tested on a large-scale test case

  9. Three-Phase Modular Cascaded H-Bridge Multilevel Inverter with Individual MPPT for Grid-Connected Photovoltaic Systems

    SciTech Connect

    Xiao, Bailu; Hang, Lijun; Riley, Cameron; Tolbert, Leon M; Ozpineci, Burak

    2013-01-01

    A three-phase modular cascaded H-bridge multilevel inverter for a grid-connected photovoltaic (PV) system is presented in this paper. To maximize the solar energy extraction of each PV string, an individual maximum power point tracking (MPPT) control scheme is applied, which allows the independent control of each dc-link voltage. PV mismatches may introduce unbalanced power supplied to the three-phase system. To solve this issue, a control scheme with modulation compensation is proposed. The three-phase modular cascaded multilevel inverter prototype has been built. Each H-bridge is connected to a 185 W solar panel. Simulation and experimental results are presented to validate the proposed ideas.

  10. An Extensible Scientific Computing Resources Integration Framework Based on Grid Service

    NASA Astrophysics Data System (ADS)

    Cui, Binge; Chen, Xin; Song, Pingjian; Liu, Rongjie

    Scientific computing resources (e.g., components, dynamic linkable libraries, etc) are very valuable assets for the scientific research. However, due to historical reasons, most computing resources can’t be shared by other people. The emergence of Grid computing provides a turning point to solve this problem. The legacy applications can be abstracted and encapsulated into Grid service, and they may be found and invoked on the Web using SOAP messages. The Grid service is loosely coupled with the external JAR or DLL, which builds a bridge from users to computing resources. We defined an XML schema to describe the functions and interfaces of the applications. This information can be acquired by users by invoking the “getCapabilities” operation of the Grid service. We also proposed the concept of class pool to eliminate the memory leaks when invoking the external jars using reflection. The experiment shows that the class pool not only avoids the PermGen space waste and Tomcat server exception, but also significantly improves the application speed. The integration framework has been implemented successfully in a real project.

  11. Integration of Grid and Sensor Web for Flood Monitoring and Risk Assessment from Heterogeneous Data

    NASA Astrophysics Data System (ADS)

    Kussul, Nataliia; Skakun, Sergii; Shelestov, Andrii

    2013-04-01

    Over last decades we have witnessed the upward global trend in natural disaster occurrence. Hydrological and meteorological disasters such as floods are the main contributors to this pattern. In recent years flood management has shifted from protection against floods to managing the risks of floods (the European Flood risk directive). In order to enable operational flood monitoring and assessment of flood risk, it is required to provide an infrastructure with standardized interfaces and services. Grid and Sensor Web can meet these requirements. In this paper we present a general approach to flood monitoring and risk assessment based on heterogeneous geospatial data acquired from multiple sources. To enable operational flood risk assessment integration of Grid and Sensor Web approaches is proposed [1]. Grid represents a distributed environment that integrates heterogeneous computing and storage resources administrated by multiple organizations. SensorWeb is an emerging paradigm for integrating heterogeneous satellite and in situ sensors and data systems into a common informational infrastructure that produces products on demand. The basic Sensor Web functionality includes sensor discovery, triggering events by observed or predicted conditions, remote data access and processing capabilities to generate and deliver data products. Sensor Web is governed by the set of standards, called Sensor Web Enablement (SWE), developed by the Open Geospatial Consortium (OGC). Different practical issues regarding integration of Sensor Web with Grids are discussed in the study. We show how the Sensor Web can benefit from using Grids and vice versa. For example, Sensor Web services such as SOS, SPS and SAS can benefit from the integration with the Grid platform like Globus Toolkit. The proposed approach is implemented within the Sensor Web framework for flood monitoring and risk assessment, and a case-study of exploiting this framework, namely the Namibia SensorWeb Pilot Project, is

  12. Strategies and Decision Support Systems for Integrating Variable Energy Resources in Control Centers for Reliable Grid Operations. Executive Summary

    SciTech Connect

    Jones, Lawrence E.

    2011-11-01

    This is the executive summary for a report that provides findings from the field regarding the best ways in which to guide operational strategies, business processes and control room tools to support the integration of renewable energy into electrical grids.

  13. Development of a flatbed passive integrated transponder antenna grid for continuous monitoring of fishes in natural streams.

    PubMed

    Johnston, P; Bérubé, F; Bergeron, N E

    2009-05-01

    This paper describes a flatbed antenna grid designed for continuous remote monitoring of fish tagged with 23 mm passive integrated transponder (PIT) tags in a natural stream with extensive spatial coverage. A range of applications of the system is presented.

  14. Strategies and Decision Support Systems for Integrating Variable Energy Resources in Control Centers for Reliable Grid Operations

    SciTech Connect

    Jones, Lawrence E.

    2011-11-01

    This report provides findings from the field regarding the best ways in which to guide operational strategies, business processes and control room tools to support the integration of renewable energy into electrical grids.

  15. Modeling, control, and simulation of grid connected intelligent hybrid battery/photovoltaic system using new hybrid fuzzy-neural method.

    PubMed

    Rezvani, Alireza; Khalili, Abbas; Mazareie, Alireza; Gandomkar, Majid

    2016-07-01

    Nowadays, photovoltaic (PV) generation is growing increasingly fast as a renewable energy source. Nevertheless, the drawback of the PV system is its dependence on weather conditions. Therefore, battery energy storage (BES) can be considered to assist for a stable and reliable output from PV generation system for loads and improve the dynamic performance of the whole generation system in grid connected mode. In this paper, a novel topology of intelligent hybrid generation systems with PV and BES in a DC-coupled structure is presented. Each photovoltaic cell has a specific point named maximum power point on its operational curve (i.e. current-voltage or power-voltage curve) in which it can generate maximum power. Irradiance and temperature changes affect these operational curves. Therefore, the nonlinear characteristic of maximum power point to environment has caused to development of different maximum power point tracking techniques. In order to capture the maximum power point (MPP), a hybrid fuzzy-neural maximum power point tracking (MPPT) method is applied in the PV system. Obtained results represent the effectiveness and superiority of the proposed method, and the average tracking efficiency of the hybrid fuzzy-neural is incremented by approximately two percentage points in comparison to the conventional methods. It has the advantages of robustness, fast response and good performance. A detailed mathematical model and a control approach of a three-phase grid-connected intelligent hybrid system have been proposed using Matlab/Simulink. PMID:26961319

  16. Economic and Environmental Assessment of a 1 MW Grid Connected Rooftop Solar PV System for Energy Efficient Building in Bangladesh

    NASA Astrophysics Data System (ADS)

    Chakraborty, Sanjib; Hosain, Rubayet; Rahman, Toufiqur; Rabbi, Ahmead Fazle

    This paper evaluates the potentiality of a 1 MW grid connected rooftop solar PV system for an Energy Efficient Building in Bangladesh, which was estimated by utilizing NASA SSE solar radiation data, PVsyst simulation software and RETScreen simulation software. Economic and environmental viability for a ten-storied building with roof area of 6,500 m2 in the Capital City of Bangladesh, Dhaka was assessed by using the RETScreen simulation software. The yearly electricity production of the proposed system was 1,581 MWh estimated by PVsyst where the technical prospective of gird-connected solar PV in Bangladesh was calculated as about 50,174 MW. The economic assessments were determined the simple payback in such a way that the generated electricity first fulfills the demand of the building, and then the rest of the energy is supplied to the grid. The result indicates that the roof top solar PV system for an Energy efficient building in Dhaka city has a favorable condition for development both in economic and environmental point of view.

  17. A Technical, Economic, and Environmental Performance of Grid-Connected Hybrid (Photovoltaic-Wind) Power System in Algeria

    PubMed Central

    Saheb-Koussa, Djohra; Koussa, Mustapha; Said, Nourredine

    2013-01-01

    This paper studies the technical, economic, and environmental analysis of wind and photovoltaic power systems connected to a conventional grid. The main interest in such systems is on-site consumption of the produced energy, system hybridization, pooling of resources, and contribution to the environment protection. To ensure a better management of system energy, models have been used for determining the power that the constituting subsystems can deliver under specific weather conditions. Simulation is performed using MATLAB-SIMULINK. While, the economic and environmental study is performed using HOMER software. From an economic point of view, this allows to compare the financial constraints on each part of the system for the case of Adrar site which is located to the northern part of the south of Algeria. It also permits to optimally size and select the system presenting the best features on the basis of two parameters, that is, cost and effectiveness. From an environmental point of view, this study allows highlighting the role of renewable energy in reducing gas emissions related to greenhouse effects. In addition, through a set of sensitivity analysis, it is found that the wind speed has more effects on the environmental and economic performances of grid-connected hybrid (photovoltaic-wind) power systems. PMID:24489488

  18. Modeling, control, and simulation of grid connected intelligent hybrid battery/photovoltaic system using new hybrid fuzzy-neural method.

    PubMed

    Rezvani, Alireza; Khalili, Abbas; Mazareie, Alireza; Gandomkar, Majid

    2016-07-01

    Nowadays, photovoltaic (PV) generation is growing increasingly fast as a renewable energy source. Nevertheless, the drawback of the PV system is its dependence on weather conditions. Therefore, battery energy storage (BES) can be considered to assist for a stable and reliable output from PV generation system for loads and improve the dynamic performance of the whole generation system in grid connected mode. In this paper, a novel topology of intelligent hybrid generation systems with PV and BES in a DC-coupled structure is presented. Each photovoltaic cell has a specific point named maximum power point on its operational curve (i.e. current-voltage or power-voltage curve) in which it can generate maximum power. Irradiance and temperature changes affect these operational curves. Therefore, the nonlinear characteristic of maximum power point to environment has caused to development of different maximum power point tracking techniques. In order to capture the maximum power point (MPP), a hybrid fuzzy-neural maximum power point tracking (MPPT) method is applied in the PV system. Obtained results represent the effectiveness and superiority of the proposed method, and the average tracking efficiency of the hybrid fuzzy-neural is incremented by approximately two percentage points in comparison to the conventional methods. It has the advantages of robustness, fast response and good performance. A detailed mathematical model and a control approach of a three-phase grid-connected intelligent hybrid system have been proposed using Matlab/Simulink.

  19. A technical, economic, and environmental performance of grid-connected hybrid (photovoltaic-wind) power system in Algeria.

    PubMed

    Saheb-Koussa, Djohra; Koussa, Mustapha; Said, Nourredine

    2013-01-01

    This paper studies the technical, economic, and environmental analysis of wind and photovoltaic power systems connected to a conventional grid. The main interest in such systems is on-site consumption of the produced energy, system hybridization, pooling of resources, and contribution to the environment protection. To ensure a better management of system energy, models have been used for determining the power that the constituting subsystems can deliver under specific weather conditions. Simulation is performed using MATLAB-SIMULINK. While, the economic and environmental study is performed using HOMER software. From an economic point of view, this allows to compare the financial constraints on each part of the system for the case of Adrar site which is located to the northern part of the south of Algeria. It also permits to optimally size and select the system presenting the best features on the basis of two parameters, that is, cost and effectiveness. From an environmental point of view, this study allows highlighting the role of renewable energy in reducing gas emissions related to greenhouse effects. In addition, through a set of sensitivity analysis, it is found that the wind speed has more effects on the environmental and economic performances of grid-connected hybrid (photovoltaic-wind) power systems.

  20. Synchrophasor Sensing and Processing based Smart Grid Security Assessment for Renewable Energy Integration

    NASA Astrophysics Data System (ADS)

    Jiang, Huaiguang

    With the evolution of energy and power systems, the emerging Smart Grid (SG) is mainly featured by distributed renewable energy generations, demand-response control and huge amount of heterogeneous data sources. Widely distributed synchrophasor sensors, such as phasor measurement units (PMUs) and fault disturbance recorders (FDRs), can record multi-modal signals, for power system situational awareness and renewable energy integration. An effective and economical approach is proposed for wide-area security assessment. This approach is based on wavelet analysis for detecting and locating the short-term and long-term faults in SG, using voltage signals collected by distributed synchrophasor sensors. A data-driven approach for fault detection, identification and location is proposed and studied. This approach is based on matching pursuit decomposition (MPD) using Gaussian atom dictionary, hidden Markov model (HMM) of real-time frequency and voltage variation features, and fault contour maps generated by machine learning algorithms in SG systems. In addition, considering the economic issues, the placement optimization of distributed synchrophasor sensors is studied to reduce the number of the sensors without affecting the accuracy and effectiveness of the proposed approach. Furthermore, because the natural hazards is a critical issue for power system security, this approach is studied under different types of faults caused by natural hazards. A fast steady-state approach is proposed for voltage security of power systems with a wind power plant connected. The impedance matrix can be calculated by the voltage and current information collected by the PMUs. Based on the impedance matrix, locations in SG can be identified, where cause the greatest impact on the voltage at the wind power plants point of interconnection. Furthermore, because this dynamic voltage security assessment method relies on time-domain simulations of faults at different locations, the proposed approach

  1. Real time hardware implementation of power converters for grid integration of distributed generation and STATCOM systems

    NASA Astrophysics Data System (ADS)

    Jaithwa, Ishan

    Deployment of smart grid technologies is accelerating. Smart grid enables bidirectional flows of energy and energy-related communications. The future electricity grid will look very different from today's power system. Large variable renewable energy sources will provide a greater portion of electricity, small DERs and energy storage systems will become more common, and utilities will operate many different kinds of energy efficiency. All of these changes will add complexity to the grid and require operators to be able to respond to fast dynamic changes to maintain system stability and security. This thesis investigates advanced control technology for grid integration of renewable energy sources and STATCOM systems by verifying them on real time hardware experiments using two different systems: d SPACE and OPAL RT. Three controls: conventional, direct vector control and the intelligent Neural network control were first simulated using Matlab to check the stability and safety of the system and were then implemented on real time hardware using the d SPACE and OPAL RT systems. The thesis then shows how dynamic-programming (DP) methods employed to train the neural networks are better than any other controllers where, an optimal control strategy is developed to ensure effective power delivery and to improve system stability. Through real time hardware implementation it is proved that the neural vector control approach produces the fastest response time, low overshoot, and, the best performance compared to the conventional standard vector control method and DCC vector control technique. Finally the entrepreneurial approach taken to drive the technologies from the lab to market via ORANGE ELECTRIC is discussed in brief.

  2. Grid Integration of Single Stage Solar PV System using Three-level Voltage Source Converter

    NASA Astrophysics Data System (ADS)

    Hussain, Ikhlaq; Kandpal, Maulik; Singh, Bhim

    2016-08-01

    This paper presents a single stage solar PV (photovoltaic) grid integrated power generating system using a three level voltage source converter (VSC) operating at low switching frequency of 900 Hz with robust synchronizing phase locked loop (RS-PLL) based control algorithm. To track the maximum power from solar PV array, an incremental conductance algorithm is used and this maximum power is fed to the grid via three-level VSC. The use of single stage system with three level VSC offers the advantage of low switching losses and the operation at high voltages and high power which results in enhancement of power quality in the proposed system. Simulated results validate the design and control algorithm under steady state and dynamic conditions.

  3. Contour integration and segmentation with a new lateral connections model

    NASA Astrophysics Data System (ADS)

    Cai, Chao

    2011-11-01

    Automatically target contour detection from cluttered scenes is a very difficult task for computer vision. Humans, however, have a much better background suppress ability. The preceding models could not implement such a task very well. In this letter, an effective contour integration method based on human visual perception mechanism is proposed. The algorithm combines the properties of primary visual cortex and psychology researching results to simulate the contour perception of the V1 cortex. The new lateral connection based computational model have a better texture suppress ability, while, target's contour is enhanced. Compared with traditional methods, experiments show that the new method implement a more reasonable simulation of the V1 function structure, availably enhance the target's contour while suppress the cluttered background, obtain a balance between over and lose detection, besides, it has better accuracy with less computational complexity and time-consuming.

  4. MAGNETIC GRID

    DOEpatents

    Post, R.F.

    1960-08-01

    An electronic grid is designed employing magnetic forces for controlling the passage of charged particles. The grid is particularly applicable to use in gas-filled tubes such as ignitrons. thyratrons, etc., since the magnetic grid action is impartial to the polarity of the charged particles and, accordingly. the sheath effects encountered with electrostatic grids are not present. The grid comprises a conductor having sections spaced apart and extending in substantially opposite directions in the same plane, the ends of the conductor being adapted for connection to a current source.

  5. Modeling Framework and Validation of a Smart Grid and Demand Response System for Wind Power Integration

    SciTech Connect

    Broeer, Torsten; Fuller, Jason C.; Tuffner, Francis K.; Chassin, David P.; Djilali, Ned

    2014-01-31

    Electricity generation from wind power and other renewable energy sources is increasing, and their variability introduces new challenges to the power system. The emergence of smart grid technologies in recent years has seen a paradigm shift in redefining the electrical system of the future, in which controlled response of the demand side is used to balance fluctuations and intermittencies from the generation side. This paper presents a modeling framework for an integrated electricity system where loads become an additional resource. The agent-based model represents a smart grid power system integrating generators, transmission, distribution, loads and market. The model incorporates generator and load controllers, allowing suppliers and demanders to bid into a Real-Time Pricing (RTP) electricity market. The modeling framework is applied to represent a physical demonstration project conducted on the Olympic Peninsula, Washington, USA, and validation simulations are performed using actual dynamic data. Wind power is then introduced into the power generation mix illustrating the potential of demand response to mitigate the impact of wind power variability, primarily through thermostatically controlled loads. The results also indicate that effective implementation of Demand Response (DR) to assist integration of variable renewable energy resources requires a diversity of loads to ensure functionality of the overall system.

  6. Modularized multilevel and z-source power converter as renewable energy interface for vehicle and grid-connected applications

    NASA Astrophysics Data System (ADS)

    Cao, Dong

    Due the energy crisis and increased oil price, renewable energy sources such as photovoltaic panel, wind turbine, or thermoelectric generation module, are used more and more widely for vehicle and grid-connected applications. However, the output of these renewable energy sources varies according to different solar radiation, wind speed, or temperature difference, a power converter interface is required for the vehicle or grid-connected applications. Thermoelectric generation (TEG) module as a renewable energy source for automotive industry is becoming very popular recently. Because of the inherent characteristics of TEG modules, a low input voltage, high input current and high voltage gain dc-dc converters are needed for the automotive load. Traditional high voltage gain dc-dc converters are not suitable for automotive application in terms of size and high temperature operation. Switched-capacitor dc-dc converters have to be used for this application. However, high voltage spike and EMI problems exist in traditional switched-capacitor dc-dc converters. Huge capacitor banks have to be utilized to reduce the voltage ripple and achieve high efficiency. A series of zero current switching (ZCS) or zero voltage switching switched-capacitor dc-dc converters have been proposed to overcome the aforementioned problems of the traditional switched-capacitor dc-dc converters. By using the proposed soft-switching strategy, high voltage spike is reduced, high EMI noise is restricted, and the huge capacitor bank is eliminated. High efficiency, high power density and high temperature switched-capacitor dc-dc converters could be made for the TEG interface in vehicle applications. Several prototypes have been made to validate the proposed circuit and confirm the circuit operation. In order to apply PV panel for grid-connected application, a low cost dc-ac inverter interface is required. From the use of transformer and safety concern, two different solutions can be implemented, non

  7. Control of Grid Connected Photovoltaic System Using Three-Level T-Type Inverter

    NASA Astrophysics Data System (ADS)

    Zorig, Abdelmalik; Belkeiri, Mohammed; Barkat, Said; Rabhi, Abdelhamid

    2016-08-01

    Three-level T-Type inverter (3LT2I) topology has numerous advantageous compared to three-level neutral-point-clamped (NPC) inverter. The main benefits of 3LT2I inverter are the efficiency, inverter cost, switching losses, and the quality of output voltage waveforms. In this paper, a photovoltaic distributed generation system based on dual-stage topology of DC-DC boost converter and 3LT2I is introduced. To that end, a decoupling control strategy of 3LT2I is proposed to control the current injected into the grid, reactive power compensation, and DC-link voltage. The resulting system is able to extract the maximum power from photovoltaic generator, to achieve sinusoidal grid currents, and to ensure reactive power compensation. The voltage-balancing control of two split DC capacitors of the 3LT2I is achieved using three-level space vector modulation with balancing strategy based on the effective use of the redundant switching states of the inverter voltage vectors. The proposed system performance is investigated at different operating conditions.

  8. Connecting Renewables Directly to the Grid: Resilient Multi-Terminal HVDC Networks with High-Voltage High-Frequency Electronics

    SciTech Connect

    2012-01-23

    GENI Project: GE is developing electricity transmission hardware that could connect distributed renewable energy sources, like wind farms, directly to the grid—eliminating the need to feed the energy generated through intermediate power conversion stations before they enter the grid. GE is using the advanced semiconductor material silicon carbide (SiC) to conduct electricity through its transmission hardware because SiC can operate at higher voltage levels than semiconductors made out of other materials. This high-voltage capability is important because electricity must be converted to high-voltage levels before it can be sent along the grid’s network of transmission lines. Power companies do this because less electricity is lost along the lines when the voltage is high.

  9. Applying the min-projection strategy to improve the transient performance of the three-phase grid-connected inverter.

    PubMed

    Baygi, Mahdi Oloumi; Ghazi, Reza; Monfared, Mohammad

    2014-07-01

    Applying the min-projection strategy (MPS) to a three-phase grid-connected inverter to improve its transient performance is the main objective of this paper. For this purpose, the inverter is first modeled as a switched linear system. Then, the feasibility of the MPS technique is investigated and the stability criterion is derived. Hereafter, the fundamental equations of the MPS for the control of the inverter are obtained. The proposed scheme is simulated in PSCAD/EMTDC environment. The validity of the MPS approach is confirmed by comparing the obtained results with those of VOC method. The results demonstrate that the proposed method despite its simplicity provides an excellent transient performance, fully decoupled control of active and reactive powers, acceptable THD level and a reasonable switching frequency.

  10. A novel multi-model neuro-fuzzy-based MPPT for three-phase grid-connected photovoltaic system

    SciTech Connect

    Chaouachi, Aymen; Kamel, Rashad M.; Nagasaka, Ken

    2010-12-15

    This paper presents a novel methodology for Maximum Power Point Tracking (MPPT) of a grid-connected 20 kW photovoltaic (PV) system using neuro-fuzzy network. The proposed method predicts the reference PV voltage guarantying optimal power transfer between the PV generator and the main utility grid. The neuro-fuzzy network is composed of a fuzzy rule-based classifier and three multi-layered feed forwarded Artificial Neural Networks (ANN). Inputs of the network (irradiance and temperature) are classified before they are fed into the appropriated ANN for either training or estimation process while the output is the reference voltage. The main advantage of the proposed methodology, comparing to a conventional single neural network-based approach, is the distinct generalization ability regarding to the nonlinear and dynamic behavior of a PV generator. In fact, the neuro-fuzzy network is a neural network based multi-model machine learning that defines a set of local models emulating the complex and nonlinear behavior of a PV generator under a wide range of operating conditions. Simulation results under several rapid irradiance variations proved that the proposed MPPT method fulfilled the highest efficiency comparing to a conventional single neural network and the Perturb and Observe (P and O) algorithm dispositive. (author)

  11. A feasibility study of stationary and dual-axis tracking grid-connected photovoltaic systems in the Upper Midwest

    NASA Astrophysics Data System (ADS)

    Warren, Ryan Duwain

    Three primary objectives were defined for this work. The first objective was to determine, assess, and compare the performance, heat transfer characteristics, economics, and feasibility of real-world stationary and dual-axis tracking grid-connected photovoltaic (PV) systems in the Upper Midwest. This objective was achieved by installing two grid-connected PV systems with different mounting schemes in central Iowa, implementing extensive data acquisition systems, monitoring operation of the PV systems for one full year, and performing detailed experimental performance and economic studies. The two PV systems that were installed, monitored, and analyzed included a 4.59 kWp roof-mounted stationary system oriented for maximum annual energy production, and a 1.02 kWp pole-mounted actively controlled dual-axis tracking system. The second objective was to demonstrate the actual use and performance of real-world stationary and dual-axis tracking grid-connected PV systems used for building energy generation applications. This objective was achieved by offering the installed PV systems to the public for demonstration purposes and through the development of three computer-based tools: a software interface that has the ability to display real-time and historical performance and meteorological data of both systems side-by-side, a software interface that shows real-time and historical video and photographs of each system, and a calculator that can predict performance and economics of stationary and dual-axis tracking grid-connected PV systems at various locations in the United States. The final objective was to disseminate this work to social, professional, scientific, and academic communities in a way that is applicable, objective, accurate, accessible, and comprehensible. This final objective will be addressed by publishing the results of this work and making the computer-based tools available on a public website (www.energy.iastate.edu/Renewable/solar). Detailed experimental

  12. Integration of a neuroimaging processing pipeline into a pan-canadian computing grid

    NASA Astrophysics Data System (ADS)

    Lavoie-Courchesne, S.; Rioux, P.; Chouinard-Decorte, F.; Sherif, T.; Rousseau, M.-E.; Das, S.; Adalat, R.; Doyon, J.; Craddock, C.; Margulies, D.; Chu, C.; Lyttelton, O.; Evans, A. C.; Bellec, P.

    2012-02-01

    The ethos of the neuroimaging field is quickly moving towards the open sharing of resources, including both imaging databases and processing tools. As a neuroimaging database represents a large volume of datasets and as neuroimaging processing pipelines are composed of heterogeneous, computationally intensive tools, such open sharing raises specific computational challenges. This motivates the design of novel dedicated computing infrastructures. This paper describes an interface between PSOM, a code-oriented pipeline development framework, and CBRAIN, a web-oriented platform for grid computing. This interface was used to integrate a PSOM-compliant pipeline for preprocessing of structural and functional magnetic resonance imaging into CBRAIN. We further tested the capacity of our infrastructure to handle a real large-scale project. A neuroimaging database including close to 1000 subjects was preprocessed using our interface and publicly released to help the participants of the ADHD-200 international competition. This successful experiment demonstrated that our integrated grid-computing platform is a powerful solution for high-throughput pipeline analysis in the field of neuroimaging.

  13. Building-to-Grid Integration through Commercial Building Portfolios Participating in Energy and Frequency Regulation Markets

    NASA Astrophysics Data System (ADS)

    Pavlak, Gregory S.

    Building energy use is a significant contributing factor to growing worldwide energy demands. In pursuit of a sustainable energy future, commercial building operations must be intelligently integrated with the electric system to increase efficiency and enable renewable generation. Toward this end, a model-based methodology was developed to estimate the capability of commercial buildings to participate in frequency regulation ancillary service markets. This methodology was integrated into a supervisory model predictive controller to optimize building operation in consideration of energy prices, demand charges, and ancillary service revenue. The supervisory control problem was extended to building portfolios to evaluate opportunities for synergistic effect among multiple, centrally-optimized buildings. Simulation studies performed showed that the multi-market optimization was able to determine appropriate opportunities for buildings to provide frequency regulation. Total savings were increased by up to thirteen percentage points, depending on the simulation case. Furthermore, optimizing buildings as a portfolio achieved up to seven additional percentage points of savings, depending on the case. Enhanced energy and cost savings opportunities were observed by taking the novel perspective of optimizing building portfolios in multiple grid markets, motivating future pursuits of advanced control paradigms that enable a more intelligent electric grid.

  14. Grid Cells and Place Cells: An Integrated View of their Navigational and Memory Function.

    PubMed

    Sanders, Honi; Rennó-Costa, César; Idiart, Marco; Lisman, John

    2015-12-01

    Much has been learned about the hippocampal/entorhinal system, but an overview of how its parts work in an integrated way is lacking. One question regards the function of entorhinal grid cells. We propose here that their fundamental function is to provide a coordinate system for producing mind-travel in the hippocampus, a process that accesses associations with upcoming positions. We further propose that mind-travel occurs during the second half of each theta cycle. By contrast, the first half of each theta cycle is devoted to computing current position using sensory information from the lateral entorhinal cortex (LEC) and path integration information from the medial entorhinal cortex (MEC). This model explains why MEC lesions can abolish hippocampal phase precession but not place fields. PMID:26616686

  15. Integrating Solar Power onto the Electric Grid - Bridging the Gap between Atmospheric Science, Engineering and Economics

    NASA Astrophysics Data System (ADS)

    Ghonima, M. S.; Yang, H.; Zhong, X.; Ozge, B.; Sahu, D. K.; Kim, C. K.; Babacan, O.; Hanna, R.; Kurtz, B.; Mejia, F. A.; Nguyen, A.; Urquhart, B.; Chow, C. W.; Mathiesen, P.; Bosch, J.; Wang, G.

    2015-12-01

    One of the main obstacles to high penetrations of solar power is the variable nature of solar power generation. To mitigate variability, grid operators have to schedule additional reliability resources, at considerable expense, to ensure that load requirements are met by generation. Thus despite the cost of solar PV decreasing, the cost of integrating solar power will increase as penetration of solar resources onto the electric grid increases. There are three principal tools currently available to mitigate variability impacts: (i) flexible generation, (ii) storage, either virtual (demand response) or physical devices and (iii) solar forecasting. Storage devices are a powerful tool capable of ensuring smooth power output from renewable resources. However, the high cost of storage is prohibitive and markets are still being designed to leverage their full potential and mitigate their limitation (e.g. empty storage). Solar forecasting provides valuable information on the daily net load profile and upcoming ramps (increasing or decreasing solar power output) thereby providing the grid advance warning to schedule ancillary generation more accurately, or curtail solar power output. In order to develop solar forecasting as a tool that can be utilized by the grid operators we identified two focus areas: (i) develop solar forecast technology and improve solar forecast accuracy and (ii) develop forecasts that can be incorporated within existing grid planning and operation infrastructure. The first issue required atmospheric science and engineering research, while the second required detailed knowledge of energy markets, and power engineering. Motivated by this background we will emphasize area (i) in this talk and provide an overview of recent advancements in solar forecasting especially in two areas: (a) Numerical modeling tools for coastal stratocumulus to improve scheduling in the day-ahead California energy market. (b) Development of a sky imager to provide short term

  16. System Efficiency of a Tap Transformer Based Grid Connection Topology Applied on a Direct Driven Generator for Wind Power

    PubMed Central

    2014-01-01

    Results from experiments on a tap transformer based grid connection system for a variable speed vertical axis wind turbine are presented. The tap transformer based system topology consists of a passive diode rectifier, DC-link, IGBT inverter, LCL-filter, and tap transformer. Full range variable speed operation is enabled by using the different step-up ratios of a tap transformer. Simulations using MATLAB/Simulink have been performed in order to study the behavior of the system. A full experimental set up of the system has been used in the laboratory study, where a clone of the on-site generator was driven by an induction motor and the system was connected to a resistive load to better evaluate the performance. Furthermore, the system is run and evaluated for realistic wind speeds and variable speed operation. For a more complete picture of the system performance, a case study using real site Weibull parameters is done, comparing different tap selection options. The results show high system efficiency at nominal power and an increase in overall power output for full tap operation in comparison with the base case, a standard transformer. In addition, the loss distribution at different wind speeds is shown, which highlights the dominant losses at low and high wind speeds. Finally, means for further increasing the overall system efficiency are proposed. PMID:25258733

  17. System efficiency of a tap transformer based grid connection topology applied on a direct driven generator for wind power.

    PubMed

    Apelfröjd, Senad; Eriksson, Sandra

    2014-01-01

    Results from experiments on a tap transformer based grid connection system for a variable speed vertical axis wind turbine are presented. The tap transformer based system topology consists of a passive diode rectifier, DC-link, IGBT inverter, LCL-filter, and tap transformer. Full range variable speed operation is enabled by using the different step-up ratios of a tap transformer. Simulations using MATLAB/Simulink have been performed in order to study the behavior of the system. A full experimental set up of the system has been used in the laboratory study, where a clone of the on-site generator was driven by an induction motor and the system was connected to a resistive load to better evaluate the performance. Furthermore, the system is run and evaluated for realistic wind speeds and variable speed operation. For a more complete picture of the system performance, a case study using real site Weibull parameters is done, comparing different tap selection options. The results show high system efficiency at nominal power and an increase in overall power output for full tap operation in comparison with the base case, a standard transformer. In addition, the loss distribution at different wind speeds is shown, which highlights the dominant losses at low and high wind speeds. Finally, means for further increasing the overall system efficiency are proposed.

  18. The Development of a Smart Distribution Grid Testbed for Integrated Information Management Systems

    SciTech Connect

    Lu, Ning; Du, Pengwei; Paulson, Patrick R.; Greitzer, Frank L.; Guo, Xinxin; Hadley, Mark D.

    2011-07-28

    This paper presents a smart distribution grid testbed to test or compare designs of integrated information management systems (I2MSs). An I2MS extracts and synthesizes information from a wide range of data sources to detect abnormal system behaviors, identify possible causes, assess the system status, and provide grid operators with response suggestions. The objective of the testbed is to provide a modeling environment with sufficient data sources for the I2MS design. The testbed includes five information layers and a physical layer; it generates multi-layer chronological data based on actual measurement playbacks or simulated data sets produced by the physical layer. The testbed models random hardware failures, human errors, extreme weather events, and deliberate tampering attempts to allow users to evaluate the performance of different I2MS designs. Initial results of I2MS performance tests showed that the testbed created a close-to-real-world environment that allowed key performance metrics of the I2MS to be evaluated.

  19. The National Grid Project: A system overview

    NASA Technical Reports Server (NTRS)

    Gaither, Adam; Gaither, Kelly; Jean, Brian; Remotigue, Michael; Whitmire, John; Soni, Bharat; Thompson, Joe; Dannenhoffer,, John; Weatherill, Nigel

    1995-01-01

    The National Grid Project (NGP) is a comprehensive numerical grid generation software system that is being developed at the National Science Foundation (NSF) Engineering Research Center (ERC) for Computational Field Simulation (CFS) at Mississippi State University (MSU). NGP is supported by a coalition of U.S. industries and federal laboratories. The objective of the NGP is to significantly decrease the amount of time it takes to generate a numerical grid for complex geometries and to increase the quality of these grids to enable computational field simulations for applications in industry. A geometric configuration can be discretized into grids (or meshes) that have two fundamental forms: structured and unstructured. Structured grids are formed by intersecting curvilinear coordinate lines and are composed of quadrilateral (2D) and hexahedral (3D) logically rectangular cells. The connectivity of a structured grid provides for trivial identification of neighboring points by incrementing coordinate indices. Unstructured grids are composed of cells of any shape (commonly triangles, quadrilaterals, tetrahedra and hexahedra), but do not have trivial identification of neighbors by incrementing an index. For unstructured grids, a set of points and an associated connectivity table is generated to define unstructured cell shapes and neighboring points. Hybrid grids are a combination of structured grids and unstructured grids. Chimera (overset) grids are intersecting or overlapping structured grids. The NGP system currently provides a user interface that integrates both 2D and 3D structured and unstructured grid generation, a solid modeling topology data management system, an internal Computer Aided Design (CAD) system based on Non-Uniform Rational B-Splines (NURBS), a journaling language, and a grid/solution visualization system.

  20. Five hundred years of gridded high-resolution precipitation reconstructions over Europe and the connection to large-scale circulation

    NASA Astrophysics Data System (ADS)

    Pauling, Andreas; Luterbacher, Jürg; Casty, Carlo; Wanner, Heinz

    2006-03-01

    We present seasonal precipitation reconstructions for European land areas (30°W to 40°E/30-71°N; given on a 0.5°×0.5° resolved grid) covering the period 1500-1900 together with gridded reanalysis from 1901 to 2000 (Mitchell and Jones 2005). Principal component regression techniques were applied to develop this dataset. A large variety of long instrumental precipitation series, precipitation indices based on documentary evidence and natural proxies (tree-ring chronologies, ice cores, corals and a speleothem) that are sensitive to precipitation signals were used as predictors. Transfer functions were derived over the 1901-1983 calibration period and applied to 1500-1900 in order to reconstruct the large-scale precipitation fields over Europe. The performance (quality estimation based on unresolved variance within the calibration period) of the reconstructions varies over centuries, seasons and space. Highest reconstructive skill was found for winter over central Europe and the Iberian Peninsula. Precipitation variability over the last half millennium reveals both large interannual and decadal fluctuations. Applying running correlations, we found major non-stationarities in the relation between large-scale circulation and regional precipitation. For several periods during the last 500 years, we identified key atmospheric modes for southern Spain/northern Morocco and central Europe as representations of two precipitation regimes. Using scaled composite analysis, we show that precipitation extremes over central Europe and southern Spain are linked to distinct pressure patterns. Due to its high spatial and temporal resolution, this dataset allows detailed studies of regional precipitation variability for all seasons, impact studies on different time and space scales, comparisons with high-resolution climate models as well as analysis of connections with regional temperature reconstructions.

  1. Fuzzy Logic Based Controller for a Grid-Connected Solid Oxide Fuel Cell Power Plant.

    PubMed

    Chatterjee, Kalyan; Shankar, Ravi; Kumar, Amit

    2014-10-01

    This paper describes a mathematical model of a solid oxide fuel cell (SOFC) power plant integrated in a multimachine power system. The utilization factor of a fuel stack maintains steady state by tuning the fuel valve in the fuel processor at a rate proportional to a current drawn from the fuel stack. A suitable fuzzy logic control is used for the overall system, its objective being controlling the current drawn by the power conditioning unit and meet a desirable output power demand. The proposed control scheme is verified through computer simulations.

  2. Fuzzy Logic Based Controller for a Grid-Connected Solid Oxide Fuel Cell Power Plant.

    PubMed

    Chatterjee, Kalyan; Shankar, Ravi; Kumar, Amit

    2014-10-01

    This paper describes a mathematical model of a solid oxide fuel cell (SOFC) power plant integrated in a multimachine power system. The utilization factor of a fuel stack maintains steady state by tuning the fuel valve in the fuel processor at a rate proportional to a current drawn from the fuel stack. A suitable fuzzy logic control is used for the overall system, its objective being controlling the current drawn by the power conditioning unit and meet a desirable output power demand. The proposed control scheme is verified through computer simulations. PMID:25053926

  3. Design of an Internal Model Control strategy for single-phase grid-connected PWM inverters and its performance analysis with a non-linear local load and weak grid.

    PubMed

    Chaves, Eric N; Coelho, Ernane A A; Carvalho, Henrique T M; Freitas, Luiz C G; Júnior, João B V; Freitas, Luiz C

    2016-09-01

    This paper presents the design of a controller based on Internal Model Control (IMC) applied to a grid-connected single-phase PWM inverter. The mathematical modeling of the inverter and the LCL output filter, used to project the 1-DOF IMC controller, is presented and the decoupling of grid voltage by a Feedforward strategy is analyzed. A Proportional - Resonant Controller (P+Res) was used for the control of the same plant in the running of experimental results, thus moving towards the discussion of differences regarding IMC and P+Res performances, which arrived at the evaluation of the proposed control strategy. The results are presented for typical conditions, for weak-grid and for non-linear local load, in order to verify the behavior of the controller against such situations. PMID:27236535

  4. Design of an Internal Model Control strategy for single-phase grid-connected PWM inverters and its performance analysis with a non-linear local load and weak grid.

    PubMed

    Chaves, Eric N; Coelho, Ernane A A; Carvalho, Henrique T M; Freitas, Luiz C G; Júnior, João B V; Freitas, Luiz C

    2016-09-01

    This paper presents the design of a controller based on Internal Model Control (IMC) applied to a grid-connected single-phase PWM inverter. The mathematical modeling of the inverter and the LCL output filter, used to project the 1-DOF IMC controller, is presented and the decoupling of grid voltage by a Feedforward strategy is analyzed. A Proportional - Resonant Controller (P+Res) was used for the control of the same plant in the running of experimental results, thus moving towards the discussion of differences regarding IMC and P+Res performances, which arrived at the evaluation of the proposed control strategy. The results are presented for typical conditions, for weak-grid and for non-linear local load, in order to verify the behavior of the controller against such situations.

  5. WNoDeS, a tool for integrated Grid and Cloud access and computing farm virtualization

    NASA Astrophysics Data System (ADS)

    Salomoni, Davide; Italiano, Alessandro; Ronchieri, Elisabetta

    2011-12-01

    INFN CNAF is the National Computing Center, located in Bologna, Italy, of the Italian National Institute for Nuclear Physics (INFN). INFN CNAF, also called the INFN Tier-1, provides computing and storage facilities to the International High-Energy Physics community and to several multi-disciplinary experiments. Currently, the INFN Tier-1 supports more than twenty different collaborations; in this context, optimization of the usage of computing resources is essential. This is one of the main drivers behind the development of a software called WNoDeS (Worker Nodes on Demand Service). WNoDeS, developed at INFN CNAF and deployed on the INFN Tier-1 production infrastructure, is a solution to virtualize computing resources and to make them available through local, Grid or Cloud interfaces. It is designed to be fully integrated with a Local Resource Management System; it is therefore inherently scalable and permits full integration with existing scheduling, policing, monitoring, accounting and security workflows. WNoDeS dynamically instantiates Virtual Machines (VMs) on-demand, i.e. only when the need arises; these VMs can be tailored and used for purposes like batch job execution, interactive analysis or service instantiation. WNoDeS supports interaction with user requests through traditional batch or Grid jobs and also via the Open Cloud Computing Interface standard, making it possible to allocate compute, storage and network resources on a pay-as-you-go basis. User authentication is supported via several authentication methods, while authorization policies are handled via gLite Argus. WNoDeS is an ambitious solution aimed at virtualizing cluster resources in medium or large scale computing centers, with up to several thousands of Virtual Machines up and running at any given time. In this paper, we descrive the WNoDeS architecture.

  6. Validation Study of the Integral-Differential Scheme for Multi-Block Grids

    NASA Astrophysics Data System (ADS)

    Mrema, Honest Frank

    This MS Thesis seeks to validate the accuracy of the Integral-Differential Scheme (IDS). In the attempts to accomplish this task, research efforts were focused on the scheme's ability to capture the physics of known flow fields, as well as the scheme's ability to predict the features of flow field quantities that may be derived from experimental measurements. The IDS was developed with the goal of being computationally efficient, from a programming perspective, as well as being numerically accurate, stable, and robust, from a mathematical perspective. The IDS is designed to solve the full Navier-Stokes equations in their integral forms. Unlike traditional control volume schemes, the IDS is built upon two sets of cells: spatial and temporal cells. For 2-D flows, the IDS considers an elementary control volume as a collection of four spatial cells and a single temporal cell. Similar to other explicit CFD schemes, the IDS relies on the use of the Taylor series expansion and other traditional CFD criteria. It is of interest to note that there are previous IDS validation studies which were conducted at North Carolina A&T State University. These past studies mainly focused on the qualitative aspects of the flow field physics. Furthermore, in all cases, they focused on flow field problems that can be represented by single-block grids. In this analysis, the validation studies are focused on multi-block grids in which the physics of the flow field is made complicated due to the presence of shock waves and flow separation zones. Of interest to this MS Thesis are two supersonic flow field problems that are supported by experimental data; namely, the supersonic flow over a rearward-facing step problem and the supersonic flow over a cavity problem. The validation studies conducted herein demonstrated that the IDS was able to predict the experimental data in both cases.

  7. Time-filtered leapfrog integration of Maxwell equations using unstaggered temporal grids

    NASA Astrophysics Data System (ADS)

    Mahalov, A.; Moustaoui, M.

    2016-11-01

    A finite-difference time-domain method for integration of Maxwell equations is presented. The computational algorithm is based on the leapfrog time stepping scheme with unstaggered temporal grids. It uses a fourth-order implicit time filter that reduces computational modes and fourth-order finite difference approximations for spatial derivatives. The method can be applied within both staggered and collocated spatial grids. It has the advantage of allowing explicit treatment of terms involving electric current density and application of selective numerical smoothing which can be used to smooth out errors generated by finite differencing. In addition, the method does not require iteration of the electric constitutive relation in nonlinear electromagnetic propagation problems. The numerical method is shown to be effective and stable when employed within Perfectly Matched Layers (PML). Stability analysis demonstrates that the proposed method is effective in stabilizing and controlling numerical instabilities of computational modes arising in wave propagation problems with physical damping and artificial smoothing terms while maintaining higher accuracy for the physical modes. Comparison of simulation results obtained from the proposed method and those computed by the classical time filtered leapfrog, where Maxwell equations are integrated for a lossy medium, within PML regions and for Kerr-nonlinear media show that the proposed method is robust and accurate. The performance of the computational algorithm is also verified by analyzing parametric four wave mixing in an optical nonlinear Kerr medium. The algorithm is found to accurately predict frequencies and amplitudes of nonlinearly converted waves under realistic conditions proposed in the literature.

  8. Using graph approach for managing connectivity in integrative landscape modelling

    NASA Astrophysics Data System (ADS)

    Rabotin, Michael; Fabre, Jean-Christophe; Libres, Aline; Lagacherie, Philippe; Crevoisier, David; Moussa, Roger

    2013-04-01

    In cultivated landscapes, a lot of landscape elements such as field boundaries, ditches or banks strongly impact water flows, mass and energy fluxes. At the watershed scale, these impacts are strongly conditionned by the connectivity of these landscape elements. An accurate representation of these elements and of their complex spatial arrangements is therefore of great importance for modelling and predicting these impacts.We developped in the framework of the OpenFLUID platform (Software Environment for Modelling Fluxes in Landscapes) a digital landscape representation that takes into account the spatial variabilities and connectivities of diverse landscape elements through the application of the graph theory concepts. The proposed landscape representation consider spatial units connected together to represent the flux exchanges or any other information exchanges. Each spatial unit of the landscape is represented as a node of a graph and relations between units as graph connections. The connections are of two types - parent-child connection and up/downstream connection - which allows OpenFLUID to handle hierarchical graphs. Connections can also carry informations and graph evolution during simulation is possible (connections or elements modifications). This graph approach allows a better genericity on landscape representation, a management of complex connections and facilitate development of new landscape representation algorithms. Graph management is fully operational in OpenFLUID for developers or modelers ; and several graph tools are available such as graph traversal algorithms or graph displays. Graph representation can be managed i) manually by the user (for example in simple catchments) through XML-based files in easily editable and readable format or ii) by using methods of the OpenFLUID-landr library which is an OpenFLUID library relying on common open-source spatial libraries (ogr vector, geos topologic vector and gdal raster libraries). Open

  9. Training Recurrent Neural Networks With the Levenberg-Marquardt Algorithm for Optimal Control of a Grid-Connected Converter.

    PubMed

    Fu, Xingang; Li, Shuhui; Fairbank, Michael; Wunsch, Donald C; Alonso, Eduardo

    2015-09-01

    This paper investigates how to train a recurrent neural network (RNN) using the Levenberg-Marquardt (LM) algorithm as well as how to implement optimal control of a grid-connected converter (GCC) using an RNN. To successfully and efficiently train an RNN using the LM algorithm, a new forward accumulation through time (FATT) algorithm is proposed to calculate the Jacobian matrix required by the LM algorithm. This paper explores how to incorporate FATT into the LM algorithm. The results show that the combination of the LM and FATT algorithms trains RNNs better than the conventional backpropagation through time algorithm. This paper presents an analytical study on the optimal control of GCCs, including theoretically ideal optimal and suboptimal controllers. To overcome the inapplicability of the optimal GCC controller under practical conditions, a new RNN controller with an improved input structure is proposed to approximate the ideal optimal controller. The performance of an ideal optimal controller and a well-trained RNN controller was compared in close to real-life power converter switching environments, demonstrating that the proposed RNN controller can achieve close to ideal optimal control performance even under low sampling rate conditions. The excellent performance of the proposed RNN controller under challenging and distorted system conditions further indicates the feasibility of using an RNN to approximate optimal control in practical applications.

  10. Connecting Distributed Energy Resources to the Grid: Their Benefits to the DER Owner etc.

    SciTech Connect

    Poore, WP

    2003-07-09

    The vision of the Distributed Energy Research Program (DER) program of the U.S. Department of Energy (DOE) is that the United States will have the cleanest and most efficient and reliable energy system in the world by maximizing the use of affordable distributed energy resources. Electricity consumers will be able to choose from a diverse number of efficient, cost-effective, and environmentally friendly distributed energy options and easily connect them into the nation's energy infrastructure while providing benefits to their owners and other stakeholders. The long-term goal of this vision is that DER will achieve a 20% share of new electric capacity additions in the United States by 2010, thereby helping to make the nation's electric power generation and delivery system more efficient, reliable, secure, clean, economical, and diverse in terms of fuel use (oil, natural gas, solar, hydroelectric, etc.) and prime mover resource (solar, wind, gas turbines, etc.). Near- and mid-term goals are to develop new technologies for implementing and operating DER and address barriers associated with DER usage and then to reduce costs and emissions and improve the efficiency and reliability of DER. Numerous strategies for meeting these goals have been developed into a research, development, and demonstration (RD&D) program that supports generation and delivery systems architecture, including modeling and simulation tools. The benefits associated with DER installations are often significant and numerous. They almost always provide tangible economic benefits, such as energy savings or transmission and distribution upgrade deferrals, as well as intangible benefits, such as power quality improvements that lengthen maintenance or repair intervals for power equipment. Also, the benefits routinely are dispersed among end users, utilities, and the public. For instance, an end user may use the DER to reduce their peak demand and save money due to lower demand charges. Reduced end user

  11. Integration of permanent magnet synchronous generator wind turbines into power grid

    NASA Astrophysics Data System (ADS)

    Abedini, Asghar

    , integrating energy storage systems with wind farms has attracted a lot of attention. These two subjects are addressed in this dissertation in detail. Permanent Magnet Synchronous Generators (PMSG) are used in variable speed wind turbines. In this thesis, the dynamic of the PMSG is investigated and a power electronic converter is designed to integrate the wind turbine to the grid. The risks of PMSG wind turbines such as low voltage ride through and short circuits, are assessed and the methods of mitigating the risks are discussed. In the second section of the thesis, various methods of smoothing wind turbine output power are explained and compared. Two novel methods of output power smoothing are analyzed: Rotor inertia and Super capacitors. The advantages and disadvantages of each method are explained and the dynamic model of each method is developed. The performance of the system is evaluated by simulating the wind turbine system in each method. The concepts of the methods of smoothing wind power can be implemented in other types of wind turbines such as Doubly Fed Induction Generator (DFIG) wind turbines.

  12. Arts Integration: An Exploration of the Dis/Connect between Policy and Live(d) Practice

    ERIC Educational Resources Information Center

    LaJevic, Lisa M.

    2009-01-01

    This dissertation explores the dis/connect between arts integration policy (i.e. written texts and curriculum documents) and the live(d) practice of teachers working with arts integration. Although previous studies have examined how arts integration is implemented in schools and how it affects student achievement, particularly standardized test…

  13. Integration and Exposure of Large Scale Computational Resources Across the Earth System Grid Federation (ESGF)

    NASA Astrophysics Data System (ADS)

    Duffy, D.; Maxwell, T. P.; Doutriaux, C.; Williams, D. N.; Chaudhary, A.; Ames, S.

    2015-12-01

    As the size of remote sensing observations and model output data grows, the volume of the data has become overwhelming, even to many scientific experts. As societies are forced to better understand, mitigate, and adapt to climate changes, the combination of Earth observation data and global climate model projects is crucial to not only scientists but to policy makers, downstream applications, and even the public. Scientific progress on understanding climate is critically dependent on the availability of a reliable infrastructure that promotes data access, management, and provenance. The Earth System Grid Federation (ESGF) has created such an environment for the Intergovernmental Panel on Climate Change (IPCC). ESGF provides a federated global cyber infrastructure for data access and management of model outputs generated for the IPCC Assessment Reports (AR). The current generation of the ESGF federated grid allows consumers of the data to find and download data with limited capabilities for server-side processing. Since the amount of data for future AR is expected to grow dramatically, ESGF is working on integrating server-side analytics throughout the federation. The ESGF Compute Working Team (CWT) has created a Web Processing Service (WPS) Application Programming Interface (API) to enable access scalable computational resources. The API is the exposure point to high performance computing resources across the federation. Specifically, the API allows users to execute simple operations, such as maximum, minimum, average, and anomalies, on ESGF data without having to download the data. These operations are executed at the ESGF data node site with access to large amounts of parallel computing capabilities. This presentation will highlight the WPS API, its capabilities, provide implementation details, and discuss future developments.

  14. An Integration Of Subgrid Physics Into Coarse Grid Simulations Of River Models

    NASA Astrophysics Data System (ADS)

    Fu, S.; Hodges, B. R.

    2007-12-01

    In river flows, the large eddies scale on river width and depth, thus the uncertainties and inhomogeneities in river boundary structure have length scales only slightly smaller the large-eddy scale. Consequently, the turbulence generated by the river bottom inhomogeneity is hydrodynamically significant. Conventionally, uncertainty and inhomogeneity in large-scale river modeling are generally addressed together by calibrating a roughness coefficient. However, this kind of calibration is inherently grid dependent due to nonlinearity associated with local flow inhomogeneity. In other words, the work to calibrate a model at one grid scale is lost if the model grid is altered, and such grid-dependent calibration cannot provide insight into the unresolved processes or features. To address the grid dependence, a Coarse Grid Simulation (CGS) framework is proposed (Fu and Hodges, 2005). The CGS will provide a model structure for representing the relationship between empirically-known subgrid features and grid-resolved flow. Therefore, the CGS will lessen the calibration efforts associated with changing model grid scales. In the present work, we demonstrate that grid resolution must affect turbulence calibration for inhomogeneous subgrid-scale physics in standard RANS formulations. Examples are provided to show that through use of the proposed CGS formalism, fine-scale process observed in a fine-grid model can be represented at arbitrary grid scales in a coarse-grid model without ad hoc calibration. Reference Fu, S. and B.R. Hodges (2005), ¡°Grid-scale dependency of subgrid-scale structure effects in hydraulic models of rivers and streams,¡± Mechanics and Materials Conference (McMat 2005), June 1-3, 2005, Louisiana State University, Baton Rouge, Electronic Proceedings (CD-ROM), 5 pgs.

  15. Empirical Analysis of the Variability of Wind Generation in India: Implications for Grid Integration

    SciTech Connect

    Phadke, Amol; Abhyankar, NIkit; Rao, Poorvi

    2014-06-17

    We analyze variability in load and wind generation in India to assess its implications for grid integration of large scale wind projects using actual wind generation and load data from two states in India, Karnataka and Tamil Nadu. We compare the largest variations in load and net load (load ?wind, i.e., load after integrating wind) that the generation fleet has to meet. In Tamil Nadu, where wind capacity is about 53percent of the peak demand, we find that the additional variation added due to wind over the current variation in load is modest; if wind penetration reaches 15percent and 30percent by energy, the additional hourly variation is less than 0.5percent and 4.5percent of the peak demand respectively for 99percent of the time. For wind penetration of 15percent by energy, Tamil Nadu system is found to be capable of meeting the additional ramping requirement for 98.8percent of the time. Potential higher uncertainty in net load compared to load is found to have limited impact on ramping capability requirements of the system if coal plants can me ramped down to 50percent of their capacity. Load and wind aggregation in Tamil Nadu and Karnataka is found to lower the variation by at least 20percent indicating the benefits geographic diversification. These findings suggest modest additional flexible capacity requirements and costs for absorbing variation in wind power and indicate that the potential capacity support (if wind does not generate enough during peak periods) may be the issue that has more bearing on the economics of integrating wind

  16. Creating Connections: Integrating the Visual Arts with Social Studies

    ERIC Educational Resources Information Center

    Burstein, Joyce H.; Knotts, Greg

    2010-01-01

    Integrating the visual and performing arts is one clear and concrete strategy to engage students in learning social studies content and concepts while making them interactive and relevant to their daily lives. In this article, the authors offer a rationale for teaching integrated arts with social studies, provide a framework for planning, and…

  17. Decision-Support Software for Grid Operators: Transmission Topology Control for Infrastructure Resilience to the Integration of Renewable Generation

    SciTech Connect

    2012-03-16

    GENI Project: The CRA team is developing control technology to help grid operators more actively manage power flows and integrate renewables by optimally turning on and off entire power lines in coordination with traditional control of generation and load resources. The control technology being developed would provide grid operators with tools to help manage transmission congestion by identifying the facilities whose on/off status must change to lower generation costs, increase utilization of renewable resources and improve system reliability. The technology is based on fast optimization algorithms for the near to real-time change in the on/off status of transmission facilities and their software implementation.

  18. Integrating subgrid connectivity properties of the micro-topography in distributed runoff models, at the interrill scale

    NASA Astrophysics Data System (ADS)

    Antoine, Michael; Javaux, Mathieu; Bielders, Charles L.

    2011-06-01

    SummaryThe spatial configuration of micro-topography affects the runoff connectivity at the interrill scale and, therefore, the shape of the hydrograph. In a previous study, we demonstrated the ability of the so-called Relative Surface Connection (RSC) function to capture, at the grid scale, the evolution of the contributing area as a function of the depression storage filling. However, this function neglects the effect of surface detention, which is proportional to the runoff rate and which must be taken into account if one wants to predict correctly the discharge dynamics. Therefore we tested two corrective procedures in association with the RSC function to integrate, at the grid scale, the effects of both depression storage and surface detention dynamics. The weighted-source corrective procedure consists in weighing the effective supply of water between depression storage and runoff using the RSC function. The weighted-surface corrective procedure consists in splitting a single grid into parallel independent strips whose sizes depend on the RSC function and which activate at various times and then participate to the global runoff production. Those methods allowed to mimic in a simple way and at the grid scale synthetical and experimental hydrographs for complex subgrid micro-topographies. The weighted-source and especially the weighted-surface corrective procedures improved the hydrograph prediction compared to the classical approach where runoff only starts when depression storage capacity is full. In a purely numerical framework with four runoff scenarios on highly contrasted micro-topographies, this improvement was reflected in a significant increase of the median Nash and Sutcliffe coefficients E50 ( E50 = 0.29 for the classical approach, E50 = 0.67 for the weighted-source procedure and E50 = 0.94 for the weighted-surface procedure). For the depression storage filling, an alternative to the Linsley equation was found and allowed a better description of

  19. Response CDF sensitivity and its solution based on sparse grid integration

    NASA Astrophysics Data System (ADS)

    Zhou, Chang-Cong; Lu, Zhen-Zhou; Hu, Ji-Xiang; Yuan, Ming

    2016-02-01

    The sensitivity of the cumulative distribution function (CDF) of the response with respect to the input parameters is studied in this work, to quantify how the model output is affected by input uncertainty. To solve the response CDF sensitivity more efficiently, a novel method based on the sparse grid integration (SGI) is proposed. The response CDF sensitivity is transformed into expressions involving probability moments, which can be efficiently estimated by the SGI technique. Once the response CDF sensitivity at one percentile level of the response is obtained, the sensitivity values at any other percentile level can be immediately obtained with no further call to the performance function. The proposed method finds a good balance between the computational burden and accuracy, and is applicable for engineering problems involving implicit performance functions. The characteristics and effectiveness of the proposed method are demonstrated by several engineering examples. Discussions on these examples have also validated the significance of the response CDF sensitivity for the purpose of variable screening and ranking.

  20. A New Control Method to Mitigate Power Fluctuations for Grid Integrated PV/Wind Hybrid Power System Using Ultracapacitors

    NASA Astrophysics Data System (ADS)

    Jayalakshmi, N. S.; Gaonkar, D. N.

    2016-08-01

    The output power obtained from solar-wind hybrid system fluctuates with changes in weather conditions. These power fluctuations cause adverse effects on the voltage, frequency and transient stability of the utility grid. In this paper, a control method is presented for power smoothing of grid integrated PV/wind hybrid system using ultracapacitors in a DC coupled structure. The power fluctuations of hybrid system are mitigated and smoothed power is supplied to the utility grid. In this work both photovoltaic (PV) panels and the wind generator are controlled to operate at their maximum power point. The grid side inverter control strategy presented in this paper maintains DC link voltage constant while injecting power to the grid at unity power factor considering different operating conditions. Actual solar irradiation and wind speed data are used in this study to evaluate the performance of the developed system using MATLAB/Simulink software. The simulation results show that output power fluctuations of solar-wind hybrid system can be significantly mitigated using the ultracapacitor based storage system.

  1. Software Based Barriers To Integration Of Renewables To The Future Distribution Grid

    SciTech Connect

    Stewart, Emma; Kiliccote, Sila

    2014-06-01

    The future distribution grid has complex analysis needs, which may not be met with the existing processes and tools. In addition there is a growing number of measured and grid model data sources becoming available. For these sources to be useful they must be accurate, and interpreted correctly. Data accuracy is a key barrier to the growth of the future distribution grid. A key goal for California, and the United States, is increasing the renewable penetration on the distribution grid. To increase this penetration measured and modeled representations of generation must be accurate and validated, giving distribution planners and operators confidence in their performance. This study will review the current state of these software and modeling barriers and opportunities for the future distribution grid.

  2. Making Training Connections: Integrating Workplace Education in Small Businesses.

    ERIC Educational Resources Information Center

    Lopez-Valadez, Jeanne; And Others

    This handbook is designed for individuals responsible for planning employee education, technical training, and other human resource development services in a workplace setting, especially in small business. It provides information on integrating basic education activities with technical training and organizational change activities to enable all…

  3. Integrating structural and functional connectivity to characterize sediment dynamics in a small Alpine catchment

    NASA Astrophysics Data System (ADS)

    Cavalli, Marco; Crema, Stefano; Blok, Michiel; Lucía, Ana; Comiti, Francesco; Marchi, Lorenzo; Keesstra, Saskia

    2016-04-01

    Sediment connectivity can be regarded as a descriptor of the internal linkages between different landscape components within a catchment. The recent focus of the scientific community on connectivity related topics, both concerning hydrological and sediment connectivity, stresses the importance of understanding the main active pathways for a better estimation of energy and matter transfer at catchment scale. This task can be addressed using topography-based indices that analyse the linkages between landscape units. This approach to characterize connectivity is known as structural connectivity. The main limitation of structural connectivity is that it does not account for the processes driving sediment and energy fluxes (i.e., functional connectivity). In this work the integration between structural and functional approaches is proposed for characterizing sediment connectivity in mountain catchments. The structural approach, based on a topography-based sediment connectivity index, was used for assessing hillslope-to-channel connectivity. Since field data on processes driving sediment transport along the channel network are available, a functional approach has been devised to estimate within-channel connectivity. An index of unit stream power computed from the hydraulic properties of the channel (i.e., discharge, slope and channel width) has been compared with the critical unit stream power computed from incipient motion thresholds derived from field data to identify the cells of the Digital Terrain Model (DTM) in which sediment can be mobilized under near-bankfull conditions. The index expressing the within-channel connectivity is given by the length of the reaches consisting of contiguous cells that exceed the critical unit stream power. During high-magnitude floods, when unit stream power values exceed the threshold for incipient motion, channels experience an increase in both hydrological and sediment connectivity. The proposed index characterizes those sections

  4. Methods of integrating a high penetration photovoltaic power plant into a micro grid.

    SciTech Connect

    Stein, Joshua S.; Johnson, Lars; Nelson, Lauren; Lenox, Carl; Johnson, Robert.

    2010-06-01

    The island of Lanai is currently one of the highest penetration PV micro grids in the world, with the 1.2 MWAC La Ola Solar Farm operating on a grid with a peak net load of 4.7 MW. This facility interconnects to one of Lanai's three 12.47 kV distribution circuits. An initial interconnection requirements study (IRS) determined that several control and performance features are necessary to ensure safe and reliable operation of the island grid. These include power curtailment, power factor control, over/under voltage and frequency ride through, and power ramp rate limiting. While deemed necessary for stable grid operation, many of these features contradict the current IEEE 1547 interconnection requirements governing distributed generators. These controls have been successfully implemented, tested, and operated since January 2009. Currently, the system is producing power in a curtailed mode according to the requirements of a power purchase agreement (PPA).

  5. Multi-Lab EV Smart Grid Integration Requirements Study. Providing Guidance on Technology Development and Demonstration

    SciTech Connect

    Markel, T.; Meintz, A.; Hardy, K.; Chen, B.; Bohn, T.; Smart, J.; Scoffield, D.; Hovsapian, R.; Saxena, S.; MacDonald, J.; Kiliccote, S.; Kahl, K.; Pratt, R.

    2015-05-28

    The report begins with a discussion of the current state of the energy and transportation systems, followed by a summary of some VGI scenarios and opportunities. The current efforts to create foundational interface standards are detailed, and the requirements for enabling PEVs as a grid resource are presented. Existing technology demonstrations that include vehicle to grid functions are summarized. The report also includes a data-based discussion on the magnitude and variability of PEVs as a grid resource, followed by an overview of existing simulation tools that vi This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. can be used to explore the expansion of VGI to larger grid functions that might offer system and customer value. The document concludes with a summary of the requirements and potential action items that would support greater adoption of VGI.

  6. Development of numerical methods for overset grids with applications for the integrated Space Shuttle vehicle

    NASA Technical Reports Server (NTRS)

    Chan, William M.

    1995-01-01

    Algorithms and computer code developments were performed for the overset grid approach to solving computational fluid dynamics problems. The techniques developed are applicable to compressible Navier-Stokes flow for any general complex configurations. The computer codes developed were tested on different complex configurations with the Space Shuttle launch vehicle configuration as the primary test bed. General, efficient and user-friendly codes were produced for grid generation, flow solution and force and moment computation.

  7. Using Conventional Hydropower to Help Alleviate Variable Resource Grid Integration Challenges in the Western U.S

    NASA Astrophysics Data System (ADS)

    Veselka, T. D.; Poch, L.

    2011-12-01

    Integrating high penetration levels of wind and solar energy resources into the power grid is a formidable challenge in virtually all interconnected systems due to the fact that supply and demand must remain in balance at all times. Since large scale electricity storage is currently not economically viable, generation must exactly match electricity demand plus energy losses in the system as time unfolds. Therefore, as generation from variable resources such as wind and solar fluctuate, production from generating resources that are easier to control and dispatch need to compensate for these fluctuations while at the same time respond to both instantaneous change in load and follow daily load profiles. The grid in the Western U.S. is not exempt to grid integration challenges associated with variable resources. However, one advantage that the power system in the Western U.S. has over many other regional power systems is that its footprint contains an abundance of hydropower resources. Hydropower plants, especially those that have reservoir water storage, can physically change electricity production levels very quickly both via a dispatcher and through automatic generation control. Since hydropower response time is typically much faster than other dispatchable resources such as steam or gas turbines, it is well suited to alleviate variable resource grid integration issues. However, despite an abundance of hydropower resources and the current low penetration of variable resources in the Western U.S., problems have already surfaced. This spring in the Pacific Northwest, wetter than normal hydropower conditions in combination with transmission constraints resulted in controversial wind resource shedding. This action was taken since water spilling would have increased dissolved oxygen levels downstream of dams thereby significantly degrading fish habitats. The extent to which hydropower resources will be able to contribute toward a stable and reliable Western grid is

  8. Musical expertise is related to altered functional connectivity during audiovisual integration.

    PubMed

    Paraskevopoulos, Evangelos; Kraneburg, Anja; Herholz, Sibylle Cornelia; Bamidis, Panagiotis D; Pantev, Christo

    2015-10-01

    The present study investigated the cortical large-scale functional network underpinning audiovisual integration via magnetoencephalographic recordings. The reorganization of this network related to long-term musical training was investigated by comparing musicians to nonmusicians. Connectivity was calculated on the basis of the estimated mutual information of the sources' activity, and the corresponding networks were statistically compared. Nonmusicians' results indicated that the cortical network associated with audiovisual integration supports visuospatial processing and attentional shifting, whereas a sparser network, related to spatial awareness supports the identification of audiovisual incongruences. In contrast, musicians' results showed enhanced connectivity in regions related to the identification of auditory pattern violations. Hence, nonmusicians rely on the processing of visual clues for the integration of audiovisual information, whereas musicians rely mostly on the corresponding auditory information. The large-scale cortical network underpinning multisensory integration is reorganized due to expertise in a cognitive domain that largely involves audiovisual integration, indicating long-term training-related neuroplasticity.

  9. Musical expertise is related to altered functional connectivity during audiovisual integration

    PubMed Central

    Paraskevopoulos, Evangelos; Kraneburg, Anja; Herholz, Sibylle Cornelia; Bamidis, Panagiotis D.; Pantev, Christo

    2015-01-01

    The present study investigated the cortical large-scale functional network underpinning audiovisual integration via magnetoencephalographic recordings. The reorganization of this network related to long-term musical training was investigated by comparing musicians to nonmusicians. Connectivity was calculated on the basis of the estimated mutual information of the sources’ activity, and the corresponding networks were statistically compared. Nonmusicians’ results indicated that the cortical network associated with audiovisual integration supports visuospatial processing and attentional shifting, whereas a sparser network, related to spatial awareness supports the identification of audiovisual incongruences. In contrast, musicians’ results showed enhanced connectivity in regions related to the identification of auditory pattern violations. Hence, nonmusicians rely on the processing of visual clues for the integration of audiovisual information, whereas musicians rely mostly on the corresponding auditory information. The large-scale cortical network underpinning multisensory integration is reorganized due to expertise in a cognitive domain that largely involves audiovisual integration, indicating long-term training-related neuroplasticity. PMID:26371305

  10. Musical expertise is related to altered functional connectivity during audiovisual integration.

    PubMed

    Paraskevopoulos, Evangelos; Kraneburg, Anja; Herholz, Sibylle Cornelia; Bamidis, Panagiotis D; Pantev, Christo

    2015-10-01

    The present study investigated the cortical large-scale functional network underpinning audiovisual integration via magnetoencephalographic recordings. The reorganization of this network related to long-term musical training was investigated by comparing musicians to nonmusicians. Connectivity was calculated on the basis of the estimated mutual information of the sources' activity, and the corresponding networks were statistically compared. Nonmusicians' results indicated that the cortical network associated with audiovisual integration supports visuospatial processing and attentional shifting, whereas a sparser network, related to spatial awareness supports the identification of audiovisual incongruences. In contrast, musicians' results showed enhanced connectivity in regions related to the identification of auditory pattern violations. Hence, nonmusicians rely on the processing of visual clues for the integration of audiovisual information, whereas musicians rely mostly on the corresponding auditory information. The large-scale cortical network underpinning multisensory integration is reorganized due to expertise in a cognitive domain that largely involves audiovisual integration, indicating long-term training-related neuroplasticity. PMID:26371305

  11. GridMan: A grid manipulation system

    NASA Technical Reports Server (NTRS)

    Eiseman, Peter R.; Wang, Zhu

    1992-01-01

    GridMan is an interactive grid manipulation system. It operates on grids to produce new grids which conform to user demands. The input grids are not constrained to come from any particular source. They may be generated by algebraic methods, elliptic methods, hyperbolic methods, parabolic methods, or some combination of methods. The methods are included in the various available structured grid generation codes. These codes perform the basic assembly function for the various elements of the initial grid. For block structured grids, the assembly can be quite complex due to a large number of clock corners, edges, and faces for which various connections and orientations must be properly identified. The grid generation codes are distinguished among themselves by their balance between interactive and automatic actions and by their modest variations in control. The basic form of GridMan provides a much more substantial level of grid control and will take its input from any of the structured grid generation codes. The communication link to the outside codes is a data file which contains the grid or section of grid.

  12. Renewable Electricity Grid Integration Roadmap for Mexico. Supplement to the IEA Expert Group Report on Recommended Practices for Wind Integration Studies

    SciTech Connect

    Parsons, Brian; Cochran, Jaquelin; Watson, Andrea; Katz, Jessica; Bracho, Ricardo

    2015-08-19

    As a recognized leader in efforts to mitigate global climate change, the Government of Mexico (GOM) works proactively to reduce emissions, demonstrating strong political will and capacity to comprehensively address climate change. Since 2010, the U.S. government (USG) has supported these efforts by partnering with Mexico under the Enhancing Capacity for Low Emission Development Strategies (EC-LEDS) program. Through the program, the USG has partnered with Mexico’s Ministry of Energy (SENER), as well as other government agencies, to support GOM in reaching its clean energy and climate change goals. Specifically, the EC-LEDS program is supporting GOM’s clean energy goal of generating 35% of its electricity from renewable energy (RE) by 2024. EC-LEDS, through the U.S. Agency for International Development (USAID) and the U.S Department of Energy’s (DOE’s) National Renewable Energy Laboratory (NREL), has been collaborating with SENER and GOM interagency working group—the Consejo Consultivo para las Energías Renovables (Consultative Council on Renewable Energy)—to create a grid integration roadmap for variable RE. 1 A key objective in creating a grid integration roadmap is assessing likely impacts of wind and solar energy on the power system and modifying planning and operations accordingly. This paper applies best practices in conducting a grid integration study to the Mexican context.

  13. PhotoVoltaic distributed generation for Lanai power grid real-time simulation and control integration scenario.

    SciTech Connect

    Robinett, Rush D., III; Kukolich, Keith; Wilson, David Gerald; Schenkman, Benjamin L.

    2010-06-01

    This paper discusses the modeling, analysis, and testing in a real-time simulation environment of the Lanai power grid system for the integration and control of PhotoVoltaic (PV) distributed generation. The Lanai Island in Hawaii is part of the Hawaii Clean Energy Initiative (HCEI) to transition to 30% renewable green energy penetration by 2030. In Lanai the primary loads come from two Castle and Cook Resorts, in addition to residential needs. The total peak load profile is 12470 V, 5.5 MW. Currently there are several diesel generators that meet these loading requirements. As part of the HCEI, Lanai has initially installed 1.2 MW of PV generation. The goal of this study has been to evaluate the impact of the PV with respect to the conventional carbon-based diesel generation in real time simulation. For intermittent PV distributed generation, the overall stability and transient responses are investigated. A simple Lanai 'like' model has been developed in the Matlab/Simulink environment (see Fig. 1) and to accommodate real-time simulation of the hybrid power grid system the Opal-RT Technologies RT-Lab environment is used. The diesel generators have been modelled using the SimPowerSystems toolbox swing equations and a custom Simulink module has been developed for the High level PV generation. All of the loads have been characterized primarily as distribution lines with series resistive load banks with one VAR load bank. Three-phase faults are implemented for each bus. Both conventional and advanced control architectures will be used to evaluate the integration of the PV onto the current power grid system. The baseline numerical results include the stable performance of the power grid during varying cloud cover (PV generation ramping up/down) scenarios. The importance of assessing the real-time scenario is included.

  14. NREL Energy Models Examine the Potential for Wind and Solar Grid Integration (Fact Sheet)

    SciTech Connect

    Not Available

    2013-11-01

    As renewable energy generating sources, such as wind turbines and solar power systems, reach high levels of penetration in parts of the United States, the National Renewable Energy Laboratory (NREL) is helping the utility industry to peer into the future. Using software modeling tools that the lab developed, NREL is examining the future operation of the electrical grid as renewable energy continues to grow.

  15. Connectivity as an alternative to boundary integral equations: Construction of bases

    PubMed Central

    Herrera, Ismael; Sabina, Federico J.

    1978-01-01

    In previous papers Herrera developed a theory of connectivity that is applicable to the problem of connecting solutions defined in different regions, which occurs when solving partial differential equations and many problems of mechanics. In this paper we explain how complete connectivity conditions can be used to replace boundary integral equations in many situations. We show that completeness is satisfied not only in steady-state problems such as potential, reduced wave equation and static and quasi-static elasticity, but also in time-dependent problems such as heat and wave equations and dynamical elasticity. A method to obtain bases of connectivity conditions, which are independent of the regions considered, is also presented. PMID:16592522

  16. Grid Interaction Technical Team Roadmap

    SciTech Connect

    2013-06-01

    The mission of the Grid Interaction Technical Team (GITT) is to support a transition scenario to large scale grid-connected vehicle charging with transformational technology, proof of concept and information dissemination. The GITT facilitates technical coordination and collaboration between vehicle-grid connectivity and communication activities among U.S. DRIVE government and industry partners.

  17. Grid-Connected Inverter Anti-Islanding Test Results for General Electric Inverter-Based Interconnection Technology

    SciTech Connect

    Ye, Z.; Dame, M.; Kroposki, B.

    2005-01-01

    This report covers testing of General Electric-proposed anti-islanding schemes. The objectives were to: (1) Validate the effectiveness of the proposed anti-islanding schemes; (2) Conduct parametric evaluation of the schemes with respect to control settings and load conditions, including controller gains, load power levels, and load quality factors; and (3) Examine the ability of the distributed resource to ride through a low-voltage condition on the utility grid.

  18. The Benefits of Grid Networks

    ERIC Educational Resources Information Center

    Tennant, Roy

    2005-01-01

    In the article, the author talks about the benefits of grid networks. In speaking of grid networks the author is referring to both networks of computers and networks of humans connected together in a grid topology. Examples are provided of how grid networks are beneficial today and the ways in which they have been used.

  19. VOLTTRON™: An Agent Platform for Integrating Electric Vehicles and Smart Grid

    SciTech Connect

    Haack, Jereme N.; Akyol, Bora A.; Tenney, Nathan D.; Carpenter, Brandon J.; Pratt, Richard M.; Carroll, Thomas E.

    2013-12-06

    The VOLTTRON™ platform provides a secure environment for the deployment of intelligent applications in the smart grid. VOLTTRON design is based on the needs of control applications running on small form factor devices, namely security and resource guarantees. Services such as resource discovery, secure agent mobility, and interacting with smart and legacy devices are provided by the platform to ease the development of control applications and accelerate their deployment. VOLTTRON platform has been demonstrated in several different domains that influenced and enhanced its capabilities. This paper will discuss the features of VOLTTRON and highlight its usage to coordinate electric vehicle charging with home energy usage

  20. Very Large-Scale Deployment of Grid-Connected Solar Photovoltaics in the United States: Challenges and Opportunities; Preprint

    SciTech Connect

    Denholm, P.; Margolis, R.

    2006-04-01

    This paper analyzes the potential for solar photovoltaics (PV) to be deployed on a very large scale and provide a large fraction of a system's electricity. It explicitly examines how the hourly availability of PV interacts with the limited flexibility of traditional electricity generation plants. The authors found that, under high penetration levels and existing grid-operation procedures and rules, the system will have excess PV generation during certain periods of the year. This excess PV generation results in increased costs, which can increase dramatically when PV provides on the order of 10%-15% of total electricity demand in systems that are heavily dependent on inflexible baseload steam plants. Measures to increase penetration of PV are also discussed, including increased system flexibility, increased dispatchable load, and energy storage.

  1. ESIF Plugs Utility-Scale Hardware into Simulated Grids to Assess Integration Effects (Fact Sheet)

    SciTech Connect

    Not Available

    2014-04-01

    At NREL's Energy Systems Integration Facility (ESIF), integrated, megawatt-scale power hardware-in-the-loop (PHIL) capability allows researchers and manufacturers to test new energy technologies at full power in real-time simulations - safely evaluating component and system performance and reliability before going to market.

  2. Results from an investigation of the integration of wind energy into the El Paso Electric grid system

    SciTech Connect

    Moroz, E.M.; Parks, N.J.; Swift, A.H.; Traichal, P.A.

    1997-12-31

    This paper documents some preliminary results from an evaluation of the costs and benefits to be gained from the integration of wind generated electricity into the El Paso Electric grid system. The study focused on the utilization of the considerable known wind potential of the Guadalupe/Delaware Mountains region, but also looked at other energetic wind resources within 15 miles of El Paso Electric`s Grid. The original project`s goal was to identify the added value of wind in terms of jobs, line support, risk reduction etc., that wind energy could bring to El Paso Electric. Although these goals have not yet been achieved the potential for water savings and reductions in gaseous emissions have been documented. Thus this paper focuses mainly on the water consumption and criteria pollutant emissions that could be avoided by adding wind energy to El Paso Electric`s generation mix. Preliminary data from a renewables attitude survey indicates that, from the 338 respondents, there is overwhelming public support for utilizing such renewable sources of electricity. This case study, which should be of direct relevance to the arid southwestern states and beyond, was sponsored by the Environmental Protection Agency (EPA) and conducted in cooperation with El Paso Electric.

  3. Building resilient power grids from integrated risk governance perspective: A lesson learned from china's 2008 Ice-Snow Storm disaster

    NASA Astrophysics Data System (ADS)

    Ye, Qian

    2014-10-01

    In the past three decades, the electric energy industry made great contribution to support rapid social and economic development in China, and meanwhile has been grown at the highest rate in the human history owing to the economic reform. In its new national development plan, more investment has been put into installation of both electricity generating capacity and transmitting capacity in order to meet fast growing demand of electric energy. However, energy resources, both fossil fuel and renewable types, and energy consumption and load centers in China are not evenly distributed in both spatial and temporal dimensions. Moreover, dominated by coal as its primary energy source, the whole eastern China is now entering an environmental crisis in which pollutants emitted by coal power plants contribute a large part. To balance the regional differences in energy sources and energy consumption while meeting the steadily increasing demands for electric energy for the whole country, in addition to increase electric generating capacity, building large-scale, long-distance ultra high voltage power grids is the top priority for next five years. China is a country prone to almost all kinds of natural disasters due to its vast, complex geographical and climatic conditions. In recent years, frequent natural disasters, especially extreme weather and climate events, have threatened the safety, reliability and stability of electric energy system in China. Unfortunately, with fast growth rate but lacking of risk assessing and prevention mechanism, many infrastructure constructions, including national power grids, are facing integrated and complex economic, social, institutional and ecological risks. In this paper, based on a case analysis of the Great Ice Storm in southern China in January 2008, risks of building a resilient power grid to deal with increasing threats from extreme weathers are discussed. The paper recommends that a systematic approach based on the social

  4. Performance Analysis of a Permanent-Magnet Induction Generator Connected to a Single-Phase Power Grid

    NASA Astrophysics Data System (ADS)

    Tsuda, Toshihiro; Fukami, Tadashi; Kanamaru, Yasunori; Miyamoto, Toshio

    In this paper, the single-phase operation of a permanent-magnet induction generator (PMIG) is analyzed theoretically and experimentally and is compared to that of a conventional induction generator (IG) of the same size to evaluate its usefulness. Phase balancing is achieved by connecting a phase converter across their stator windings. Based on the method of symmetrical components, the steady-state performance of both the PMIG and the IG is theoretically predicted, and the results are verified through experiments. The PMIG exhibits a higher performance, in terms of output power, power factor, and efficiency, than the conventional IG.

  5. Connected health and integrated care: Toward new models for chronic disease management.

    PubMed

    Chouvarda, Ioanna G; Goulis, Dimitrios G; Lambrinoudaki, Irene; Maglaveras, Nicos

    2015-09-01

    The increasingly aging population in Europe and worldwide brings up the need for the restructuring of healthcare. Technological advancements in electronic health can be a driving force for new health management models, especially in chronic care. In a patient-centered e-health management model, communication and coordination between patient, healthcare professionals in primary care and hospitals can be facilitated, and medical decisions can be made timely and easily communicated. Bringing the right information to the right person at the right time is what connected health aims at, and this may set the basis for the investigation and deployment of the integrated care models. In this framework, an overview of the main technological axes and challenges around connected health technologies in chronic disease management are presented and discussed. A central concept is personal health system for the patient/citizen and three main application areas are identified. The connected health ecosystem is making progress, already shows benefits in (a) new biosensors, (b) data management, (c) data analytics, integration and feedback. Examples are illustrated in each case, while open issues and challenges for further research and development are pinpointed.

  6. Comparative Evaluation for Brain Structural Connectivity Approaches: Towards Integrative Neuroinformatics Tool for Epilepsy Clinical Research.

    PubMed

    Yang, Sheng; Tatsuoka, Curtis; Ghosh, Kaushik; Lacuey-Lecumberri, Nuria; Lhatoo, Samden D; Sahoo, Satya S

    2016-01-01

    Recent advances in brain fiber tractography algorithms and diffusion Magnetic Resonance Imaging (MRI) data collection techniques are providing new approaches to study brain white matter connectivity, which play an important role in complex neurological disorders such as epilepsy. Epilepsy affects approximately 50 million persons worldwide and it is often described as a disorder of the cortical network organization. There is growing recognition of the need to better understand the role of brain structural networks in the onset and propagation of seizures in epilepsy using high resolution non-invasive imaging technologies. In this paper, we perform a comparative evaluation of two techniques to compute structural connectivity, namely probabilistic fiber tractography and statistics derived from fractional anisotropy (FA), using diffusion MRI data from a patient with rare case of medically intractable insular epilepsy. The results of our evaluation demonstrate that probabilistic fiber tractography provides a more accurate map of structural connectivity and may help address inherent complexities of neural fiber layout in the brain, such as fiber crossings. This work provides an initial result towards building an integrative informatics tool for neuroscience that can be used to accurately characterize the role of fiber tract connectivity in neurological disorders such as epilepsy. PMID:27570685

  7. Comparative Evaluation for Brain Structural Connectivity Approaches: Towards Integrative Neuroinformatics Tool for Epilepsy Clinical Research

    PubMed Central

    Yang, Sheng; Tatsuoka, Curtis; Ghosh, Kaushik; Lacuey-Lecumberri, Nuria; Lhatoo, Samden D.; Sahoo, Satya S.

    2016-01-01

    Recent advances in brain fiber tractography algorithms and diffusion Magnetic Resonance Imaging (MRI) data collection techniques are providing new approaches to study brain white matter connectivity, which play an important role in complex neurological disorders such as epilepsy. Epilepsy affects approximately 50 million persons worldwide and it is often described as a disorder of the cortical network organization. There is growing recognition of the need to better understand the role of brain structural networks in the onset and propagation of seizures in epilepsy using high resolution non-invasive imaging technologies. In this paper, we perform a comparative evaluation of two techniques to compute structural connectivity, namely probabilistic fiber tractography and statistics derived from fractional anisotropy (FA), using diffusion MRI data from a patient with rare case of medically intractable insular epilepsy. The results of our evaluation demonstrate that probabilistic fiber tractography provides a more accurate map of structural connectivity and may help address inherent complexities of neural fiber layout in the brain, such as fiber crossings. This work provides an initial result towards building an integrative informatics tool for neuroscience that can be used to accurately characterize the role of fiber tract connectivity in neurological disorders such as epilepsy. PMID:27570685

  8. Connective tissue integrity is lost in vitamin B-6-deficient chicks

    NASA Technical Reports Server (NTRS)

    Masse, P. G.; Yamauchi, M.; Mahuren, J. D.; Coburn, S. P.; Muniz, O. E.; Howell, D. S.

    1995-01-01

    The objective of the present investigation was to characterize further the connective tissue disorder produced by pyridoxine (vitamin B-6) deficiency, as previously evidenced by electron microscopy. Following the second post-natal week, fast growing male chicks were deprived of pyridoxine for a 1-mo period. Six weeks post-natally, blood concentrations in the experimental deficiency group had declined to deficiency levels as registered by low concentrations of pyridoxal phosphate (coenzyme form) in erythrocytes, but did not reach levels associated with neurological symptoms. Light microscopic study showed abnormalities in the extracellular matrix of the connective tissues. Collagen cross-links and the aldehyde contents were not significantly lower in cartilage and tendon collagens of vitamin B-6-deficient animals than in age-matched controls; also, their proteoglycan degrading protease and collagenase activities measured in articular cartilages were not greater. Thus, proteolysis was an unlikely alternative mechanism to account for the loss of connective tissue integrity. These results point to the need for further investigation into adhesive properties of collagen associated proteoglycans or other proteins in vitamin B-6-deficient connective tissue.

  9. Precise uniform light source based on optically connected integrating spheres for optical instrument calibration

    NASA Astrophysics Data System (ADS)

    Mikheenko, Leonid; Borovytsky, Volodymyr

    2011-09-01

    The paper proposes the uniform light sources which have a form of several or multiple optically connected integrating spheres. The principal advantages of these light sources are high photometric and metrological characteristics. As a result they have good perspectives in optical radiometry and calibration of imaging systems and optical instruments. The principal field of their application is calibration of remote sensing instruments and sensitive megapixel cameras. The light source contains several (3 ... 11) primary integrating spheres of small diameters which are installed on a secondary integrating sphere of bigger diameter. The initial light sources - halogen lamps or light emitted diodes are installed inside the primary integrating spheres. These spheres are mounted on the secondary integrating sphere. The radiation comes from the primary integrating spheres to the secondary one through diaphragms which diameters can be varied. The secondary integrating sphere has an output aperture where uniform radiance emits. It is investigated the light source design with an output aperture diameter 0.2 m and 3 or 5 primary integrating spheres. It guarantees the output radiance in range from 0.01 to 1000 W/(st•m2), radiance uniformity bigger 99.5% in an output aperture, non-linearity of an output radiance control - smaller 0.1 %. The paper presents the results of theoretical and experimental research of these light sources including the techniques for radiance calculation and the recommendations for light source design. The proposed light sources can be considered as one of the best candidates for calibration of remote sensing instruments working in optical range 0.4 - 2.2 mkm. Key words: integrating sphere, light source, calibration, uniformity, radiance, remote sensing, optical instrument.

  10. Metrological advantages of the light source based on optically connected integrating spheres

    NASA Astrophysics Data System (ADS)

    Mikheenko, Leonid; Borovytsky, Volodymyr

    2012-10-01

    The paper presents the metrological analysis of the light sources which have a form of several optically connected integrating spheres. This light sources contain several (3 ... 11) primary integrating spheres of small diameters that are installed on a secondary integrating sphere of bigger diameter. The initial light sources - halogen lamps or light emitted diodes are installed inside the primary integrating spheres. These spheres are mounted on the secondary integrating sphere. The radiation comes from the primary integrating spheres to the secondary one through the diaphragms which diameters can be varied. It makes possible to control the total flux coming through the diaphragms and to set the required output radiance. The secondary integrating sphere has an output aperture where uniform radiance emits. The paper discusses the technique for calculation of the precision of the output radiance according to variations of optical and geometrical parameters of the light source. There are investigated influences of power supply, reflectance properties, diameters of internal surfaces of the integrating spheres and diameters of diaphragms between the integrating spheres. The precision of the output radiance is better than 1.9 % for the non-expensive light sources. For the high-quality light sources it can reach 0.7 %. The possible range of the output radiance is from 0 to 1 200 W/(st•m2). These facts confirm the sufficient metrological advantages of the proposed light sources for absolute radiometric measurements. The proposed light sources can be considered as one of the best candidates for calibration of the modern remote sensing instruments and high quality imaging systems working in optical range 0.4 - 2.2 μkm.

  11. Optimizing Aggregation Scenarios for Integrating Renewable Energy into the U.S. Electric Grid

    NASA Astrophysics Data System (ADS)

    Corcoran, B. A.; Jacobson, M. Z.

    2010-12-01

    This study is an analysis of 2006 and 2007 electric load data, wind speed and solar irradiance data, and existing hydroelectric, geothermal, and other power plant data to quantify benefits of aggregating clean electric power from various Federal Energy Regulatory Commission (FERC) regions in the contiguous United States. First, various time series, statistics, and probability methods are applied to the electric load data to determine if there are any desirable demand-side results—specifically reducing variability and/or coincidence of peak events, which could reduce the amount of required carbon-based generators—in combining the electricity demands from geographically and temporally diverse areas. Second, an optimization algorithm is applied to determine the least-cost portfolio of energy resources to meet the electric load for a range of renewable portfolio standards (RPS’s) for each FERC region and for various aggregation scenarios. Finally, the installed capacities, ramp rates, standard deviation, and corresponding generator requirements from these optimization test runs are compared against the transmission requirements to determine the most economical organizational structure of the contiguous U.S. electric grid. Ideally, results from this study will help to justify and identify a possible structure of a federal RPS and offer insight into how to best organize regions for transmission planning.

  12. Van Geet Off-Grid Home: An Integrated Approach to Energy Savings

    SciTech Connect

    Barley, C. D.; Torcellini, P.; Van Geet, O.

    2004-08-01

    The Van Geet home near Denver, Colorado, exemplifies the effectiveness of coupling energy conservation measures with renewable energy utilization in a modern residence. The remote location, with no utility connections available, and the owner's interest in renewable energy motivated the ambitious design. This design attracted the interest of the Building America (BA) program and was studied as a research home. As a result, the BA program provided energy engineering throughout the design, construction, and performance evaluation phases. The American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) also recognized the success of this project by awarding it an ASHRAE Technology Award in 2001.

  13. Modelling the potential for wind energy integration on China’s coal-heavy electricity grid

    NASA Astrophysics Data System (ADS)

    Davidson, Michael R.; Zhang, Da; Xiong, Weiming; Zhang, Xiliang; Karplus, Valerie J.

    2016-07-01

    Expanding the use of wind energy for electricity generation forms an integral part of China’s efforts to address degraded air quality and climate change. However, the integration of wind energy into China’s coal-heavy electricity system presents significant challenges owing to wind’s variability and the grid’s system-wide inflexibilities. Here we develop a model to predict how much wind energy can be generated and integrated into China’s electricity mix, and estimate a potential production of 2.6 petawatt-hours (PWh) per year in 2030. Although this represents 26% of total projected electricity demand, it is only 10% of the total estimated physical potential of wind resources in the country. Increasing the operational flexibility of China’s coal fleet would allow wind to deliver nearly three-quarters of China’s target of producing 20% of primary energy from non-fossil sources by 2030.

  14. Integrated Care and Connected Health Approaches Leveraging Personalised Health through Big Data Analytics.

    PubMed

    Maglaveras, Nicos; Kilintzis, Vassilis; Koutkias, Vassilis; Chouvarda, Ioanna

    2016-01-01

    Integrated care and connected health are two fast evolving concepts that have the potential to leverage personalised health. From the one side, the restructuring of care models and implementation of new systems and integrated care programs providing coaching and advanced intervention possibilities, enable medical decision support and personalized healthcare services. From the other side, the connected health ecosystem builds the means to follow and support citizens via personal health systems in their everyday activities and, thus, give rise to an unprecedented wealth of data. These approaches are leading to the deluge of complex data, as well as in new types of interactions with and among users of the healthcare ecosystem. The main challenges refer to the data layer, the information layer, and the output of information processing and analytics. In all the above mentioned layers, the primary concern is the quality both in data and information, thus, increasing the need for filtering mechanisms. Especially in the data layer, the big biodata management and analytics ecosystem is evolving, telemonitoring is a step forward for data quality leverage, with numerous challenges still left to address, partly due to the large number of micro-nano sensors and technologies available today, as well as the heterogeneity in the users' background and data sources. This leads to new R&D pathways as it concerns biomedical information processing and management, as well as to the design of new intelligent decision support systems (DSS) and interventions for patients. In this paper, we illustrate these issues through exemplar research targeting chronic patients, illustrating the current status and trends in PHS within the integrated care and connected care world.

  15. Integrated Care and Connected Health Approaches Leveraging Personalised Health through Big Data Analytics.

    PubMed

    Maglaveras, Nicos; Kilintzis, Vassilis; Koutkias, Vassilis; Chouvarda, Ioanna

    2016-01-01

    Integrated care and connected health are two fast evolving concepts that have the potential to leverage personalised health. From the one side, the restructuring of care models and implementation of new systems and integrated care programs providing coaching and advanced intervention possibilities, enable medical decision support and personalized healthcare services. From the other side, the connected health ecosystem builds the means to follow and support citizens via personal health systems in their everyday activities and, thus, give rise to an unprecedented wealth of data. These approaches are leading to the deluge of complex data, as well as in new types of interactions with and among users of the healthcare ecosystem. The main challenges refer to the data layer, the information layer, and the output of information processing and analytics. In all the above mentioned layers, the primary concern is the quality both in data and information, thus, increasing the need for filtering mechanisms. Especially in the data layer, the big biodata management and analytics ecosystem is evolving, telemonitoring is a step forward for data quality leverage, with numerous challenges still left to address, partly due to the large number of micro-nano sensors and technologies available today, as well as the heterogeneity in the users' background and data sources. This leads to new R&D pathways as it concerns biomedical information processing and management, as well as to the design of new intelligent decision support systems (DSS) and interventions for patients. In this paper, we illustrate these issues through exemplar research targeting chronic patients, illustrating the current status and trends in PHS within the integrated care and connected care world. PMID:27225565

  16. Grid-scale Indirect Radiative Forcing of Climate due to aerosols over the northern hemisphere simulated by the integrated WRF-CMAQ model: Preliminary results

    EPA Science Inventory

    In this study, indirect aerosol effects on grid-scale clouds were implemented in the integrated WRF3.3-CMAQ5.0 modeling system by including parameterizations for both cloud droplet and ice number concentrations calculated from the CMAQ-predicted aerosol particles. The resulting c...

  17. Integration of photovoltaic units into electric utility grids: experiment information requirements and selected issues

    SciTech Connect

    Not Available

    1980-09-01

    A number of investigations, including those conducted by The Aerospace Corporation and other contractors, have led to the recognition of technical, economic, and institutional issues relating to the interface between solar electric technologies and electric utility systems. These issues derive from three attributes of solar electric power concepts, including (1) the variability and unpredictability of the solar resources, (2) the dispersed nature of those resources which suggests the feasible deployment of small dispersed power units, and (3) a high initial capital cost coupled with relatively low operating costs. It is imperative that these integration issues be pursued in parallel with the development of each technology if the nation's electric utility systems are to effectively utilize these technologies in the near to intermediate term. Analyses of three of these issues are presented: utility information requirements, generation mix and production cost impacts, and rate structures in the context of photovoltaic units integrated into the utility system. (WHK)

  18. Grid Integration of Aggregated Demand Response, Part 2: Modeling Demand Response in a Production Cost Model

    SciTech Connect

    Hummon, Marissa; Palchak, David; Denholm, Paul; Jorgenson, Jennie; Olsen, Daniel J.; Kiliccote, Sila; Matson, Nance; Sohn, Michael; Rose, Cody; Dudley, Junqiao; Goli, Sasank; Ma, Ookie

    2013-12-01

    This report is one of a series stemming from the U.S. Department of Energy (DOE) Demand Response and Energy Storage Integration Study. This study is a multi-national-laboratory effort to assess the potential value of demand response (DR) and energy storage to electricity systems with different penetration levels of variable renewable resources and to improve our understanding of associatedmarkets and institutions. This report implements DR resources in the commercial production cost model PLEXOS.

  19. Performance of heterogeneous computing with graphics processing unit and many integrated core for hartree potential calculations on a numerical grid.

    PubMed

    Choi, Sunghwan; Kwon, Oh-Kyoung; Kim, Jaewook; Kim, Woo Youn

    2016-09-15

    We investigated the performance of heterogeneous computing with graphics processing units (GPUs) and many integrated core (MIC) with 20 CPU cores (20×CPU). As a practical example toward large scale electronic structure calculations using grid-based methods, we evaluated the Hartree potentials of silver nanoparticles with various sizes (3.1, 3.7, 4.9, 6.1, and 6.9 nm) via a direct integral method supported by the sinc basis set. The so-called work stealing scheduler was used for efficient heterogeneous computing via the balanced dynamic distribution of workloads between all processors on a given architecture without any prior information on their individual performances. 20×CPU + 1GPU was up to ∼1.5 and ∼3.1 times faster than 1GPU and 20×CPU, respectively. 20×CPU + 2GPU was ∼4.3 times faster than 20×CPU. The performance enhancement by CPU + MIC was considerably lower than expected because of the large initialization overhead of MIC, although its theoretical performance is similar with that of CPU + GPU. © 2016 Wiley Periodicals, Inc. PMID:27431905

  20. Performance of heterogeneous computing with graphics processing unit and many integrated core for hartree potential calculations on a numerical grid.

    PubMed

    Choi, Sunghwan; Kwon, Oh-Kyoung; Kim, Jaewook; Kim, Woo Youn

    2016-09-15

    We investigated the performance of heterogeneous computing with graphics processing units (GPUs) and many integrated core (MIC) with 20 CPU cores (20×CPU). As a practical example toward large scale electronic structure calculations using grid-based methods, we evaluated the Hartree potentials of silver nanoparticles with various sizes (3.1, 3.7, 4.9, 6.1, and 6.9 nm) via a direct integral method supported by the sinc basis set. The so-called work stealing scheduler was used for efficient heterogeneous computing via the balanced dynamic distribution of workloads between all processors on a given architecture without any prior information on their individual performances. 20×CPU + 1GPU was up to ∼1.5 and ∼3.1 times faster than 1GPU and 20×CPU, respectively. 20×CPU + 2GPU was ∼4.3 times faster than 20×CPU. The performance enhancement by CPU + MIC was considerably lower than expected because of the large initialization overhead of MIC, although its theoretical performance is similar with that of CPU + GPU. © 2016 Wiley Periodicals, Inc.

  1. The air quality and human health effects of integrating utility-scale batteries into the New York State electricity grid

    NASA Astrophysics Data System (ADS)

    Gilmore, Elisabeth A.; Apt, Jay; Walawalkar, Rahul; Adams, Peter J.; Lave, Lester B.

    In a restructured electricity market, utility-scale energy storage technologies such as advanced batteries can generate revenue by charging at low electricity prices and discharging at high prices. This strategy changes the magnitude and distribution of air quality emissions and the total carbon dioxide (CO 2) emissions. We evaluate the social costs associated with these changes using a case study of 500 MW sodium-sulfur battery installations with 80% round-trip efficiency. The batteries displace peaking generators in New York City and charge using off-peak generation in the New York Independent System Operator (NYISO) electricity grid during the summer. We identify and map charging and displaced plant types to generators in the NYISO. We then convert the emissions into ambient concentrations with a chemical transport model, the Particulate Matter Comprehensive Air Quality Model with extensions (PMCAM x). Finally, we transform the concentrations into their equivalent human health effects and social benefits and costs. Reductions in premature mortality from fine particulate matter (PM 2.5) result in a benefit of 4.5 ¢ kWh -1 and 17 ¢ kWh -1 from displacing a natural gas and distillate fuel oil fueled peaking plant, respectively, in New York City. Ozone (O 3) concentrations increase due to decreases in nitrogen oxide (NO x) emissions, although the magnitude of the social cost is less certain. Adding the costs from charging, displacing a distillate fuel oil plant yields a net social benefit, while displacing the natural gas plant has a net social cost. With the existing base-load capacity, the upstate population experiences an increase in adverse health effects. If wind generation is charging the battery, both the upstate charging location and New York City benefit. At 20 per tonne of CO 2, the costs from CO 2 are small compared to those from air quality. We conclude that storage could be added to existing electricity grids as part of an integrated strategy from a

  2. The Association of Aging with White Matter Integrity and Functional Connectivity Hubs

    PubMed Central

    Yang, Albert C.; Tsai, Shih-Jen; Liu, Mu-En; Huang, Chu-Chung; Lin, Ching-Po

    2016-01-01

    Normal aging is associated with reduced cerebral structural integrity and altered functional brain activity, yet the association of aging with the relationship between structural and functional brain changes remains unclear. Using combined diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI) modalities, we hypothesized that aging-related changes in white matter integrity (i.e., fractional anisotropy) was associated with the short- or long-range functional connectivity density (FCD) in hub regions. We tested this hypothesis by using a healthy aging cohort comprised of 140 younger adults aged 20–39 years and 109 older adults aged 60–79 years. Compared with the younger group, older adults exhibited widespread reductions in white matter integrity with selective preservation in brain stem tracts and the cingulum connected to the hippocampus and cingulate cortex, whereas FCD mapping in older adults showed a reduced FCD in the visual, somatosensory, and motor functional networks and an increased FCD in the default mode network. The older adults exhibited significantly increased short- or long-range FCD in functional hubs of the precuneus, posterior, and middle cingulate, and thalamus, hippocampus, fusiform, and inferior temporal cortex. Furthermore, DTI-fMRI relationship were predominantly identified in older adults in whom short- and long-range FCD in the left precuneus was negatively correlated to structural integrity of adjacent and nonadjacent white matter tracts, respectively. We also found that long-range FCD in the left precuneus was positively correlated to cognitive function. These results support the compensatory hypothesis of neurocognitive aging theory and reveal the DTI-fMRI relationship associated with normal aging. PMID:27378915

  3. Developmental synaptic changes increase the range of integrative capabilities of an identified excitatory neocortical connection.

    PubMed

    Angulo, M C; Staiger, J F; Rossier, J; Audinat, E

    1999-03-01

    Excitatory synaptic transmission between pyramidal cells and fast-spiking (FS) interneurons of layer V of the motor cortex was investigated in acute slices by using paired recordings at 30 degrees C combined with morphological analysis. The presynaptic and postsynaptic properties at these identified central synapses were compared between 3- and 5-week-old rats. At these two postnatal developmental stages, unitary EPSCs were mediated by the activation of AMPA receptors with fast kinetics at a holding potential of -72 mV. The amplitude distribution analysis of the EPSCs indicates that, at both stages, pyramidal-FS connections consisted of multiple functional release sites. The apparent quantal size obtained by decreasing the external calcium ([Ca2+]e) varied from 11 to 29 pA near resting membrane potential. In young rats, pairs of presynaptic action potentials elicited unitary synaptic responses that displayed paired-pulse depression at all tested frequencies. In older animals, inputs from different pyramidal cells onto the same FS interneuron had different paired-pulse response characteristics and, at most of these connections, a switch from depression to facilitation occurred when decreasing the rate of presynaptic stimulation. The balance between facilitation and depression endows pyramidal-FS connections from 5-week-old animals with wide integrative capabilities and confers unique functional properties to each synapse.

  4. Integrated routing and fill for self-aligned double patterning (SADP) using grid-based design

    NASA Astrophysics Data System (ADS)

    Song, Youngsoo; Lee, Jeemyung; Lee, Seongmin; Shin, Youngsoo

    2016-03-01

    Self-aligned double patterning (SADP) has been proposed as an alternative patterning solution for sub-10nm technology because of delay of advanced lithography beyond 193nm ArF. In conventional SADP, line and space style of dummy metal fills are inserted once main design is complete. A large buffer distance is required around the main design because no further verification of main design (in presence of fills) is performed. This causes irregular pattern density, which becomes a source of process variations. We propose integrated-fill, in which main design and dummy fill insertion are performed together. This requires a change in overall design flow, which we discuss. Integrated-fill is demonstrated in M2 layer of SADP process; M2 density increases by 15.7% with 2.3% reduction in standard deviation of density distribution; metal thickness variation is also reduced by 24%. More dummy fills cause increased coupling capacitance, which however is shown to be insignificant.

  5. Heteromodal connections supporting multisensory integration at low levels of cortical processing in the monkey.

    PubMed

    Cappe, Céline; Barone, Pascal

    2005-12-01

    While multisensory integration is thought to occur in higher hierarchical cortical areas, recent studies in man and monkey have revealed plurisensory modulations of activity in areas previously thought to be unimodal. To determine the cortical network involved in multisensory interactions, we performed multiple injections of different retrograde tracers in unimodal auditory (core), somatosensory (1/3b) and visual (V2 and MT) cortical areas of the marmoset. We found three types of heteromodal connections linking unimodal sensory areas. Visuo-somatosensory projections were observed originating from visual areas [probably the ventral and dorsal fundus of the superior temporal area (FSTv and FSTd), and middle temporal crescent (MTc)] toward areas 1/3b. Somatosensory projections to the auditory cortex were present from S2 and the anterior bank of the lateral sulcus. Finally, a visuo-auditory projection arises from an area anterior to the superior temporal sulcus (STS) toward the auditory core. Injections in different sensory regions allow us to define the frontal convexity and the temporal opercular caudal cortex as putative polysensory areas. A quantitative analysis of the laminar distribution of projecting neurons showed that heteromodal connections could be either feedback or feedforward. Taken together, our results provide the anatomical pathway for multisensory integration at low levels of information processing in the primate and argue against a strict hierarchical model.

  6. An Efficient Grid Generation Method for Arbitrary Domains

    NASA Astrophysics Data System (ADS)

    Orme, Melissa; Huang, Changzheng

    1997-11-01

    This paper describes an efficient grid generation method for arbitrary or multiply connected domains. Our method, essentially based on the edge swapping techniques, combines the advantages of the Delaunay triangulation method and the advancing front method. The latter two methods are in popular use nowadays. But both suffer some limitations. Delaunay method generates high quality grid but grid may cut across the boundary in concave regions. Advancing front method works for general domain but may encounter difficulties where fronts have to be merged. The current method garantees the boundary integrity and attains the nice Delaunay features into the domain. This is achieved by carefully documenting the grid information so that each edge is readily identified to be inside or outside the domain; and (2) continuously swapping out those bad edges that destroy the Delaunay properties. The computer program built on this method allows users to control the grid density distribution by specifying typical grid sizes on a few chosen points. Interesting examples are demonstrated here. One of them is a circular domain with three letters APS inside. (see figure 1 and figure 2 ). Given a grid size for APS and another size for the circle, the program automatically generates a smooth triangular grid regardless of the complex multiply connected geometry.

  7. Integrating Sediment Connectivity into Water Resources Management Trough a Graph Theoretic, Stochastic Modeling Framework.

    NASA Astrophysics Data System (ADS)

    Schmitt, R. J. P.; Castelletti, A.; Bizzi, S.

    2014-12-01

    Understanding sediment transport processes at the river basin scale, their temporal spectra and spatial patterns is key to identify and minimize morphologic risks associated to channel adjustments processes. This work contributes a stochastic framework for modeling bed-load connectivity based on recent advances in the field (e.g., Bizzi & Lerner, 2013; Czubas & Foufoulas-Georgiu, 2014). It presents river managers with novel indicators from reach scale vulnerability to channel adjustment in large river networks with sparse hydrologic and sediment observations. The framework comprises three steps. First, based on a distributed hydrological model and remotely sensed information, the framework identifies a representative grain size class for each reach. Second, sediment residence time distributions are calculated for each reach in a Monte-Carlo approach applying standard sediment transport equations driven by local hydraulic conditions. Third, a network analysis defines the up- and downstream connectivity for various travel times resulting in characteristic up/downstream connectivity signatures for each reach. Channel vulnerability indicators quantify the imbalance between up/downstream connectivity for each travel time domain, representing process dependent latency of morphologic response. Last, based on the stochastic core of the model, a sensitivity analysis identifies drivers of change and major sources of uncertainty in order to target key detrimental processes and to guide effective gathering of additional data. The application, limitation and integration into a decision analytic framework is demonstrated for a major part of the Red River Basin in Northern Vietnam (179.000 km2). Here, a plethora of anthropic alterations ranging from large reservoir construction to land-use changes results in major downstream deterioration and calls for deriving concerted sediment management strategies to mitigate current and limit future morphologic alterations.

  8. Hydrologic connectivity and the contribution of stream headwaters to ecological integrity at regional scales

    USGS Publications Warehouse

    Freeman, Mary C.; Pringle, C.M.; Jackson, C.R.

    2007-01-01

    Cumulatively, headwater streams contribute to maintaining hydrologic connectivity and ecosystem integrity at regional scales. Hydrologic connectivity is the water-mediated transport of matter, energy and organisms within or between elements of the hydrologic cycle. Headwater streams compose over two-thirds of total stream length in a typical river drainage and directly connect the upland and riparian landscape to the rest of the stream ecosystem. Altering headwater streams, e.g., by channelization, diversion through pipes, impoundment and burial, modifies fluxes between uplands and downstream river segments and eliminates distinctive habitats. The large-scale ecological effects of altering headwaters are amplified by land uses that alter runoff and nutrient loads to streams, and by widespread dam construction on larger rivers (which frequently leaves free-flowing upstream portions of river systems essential to sustaining aquatic biodiversity). We discuss three examples of large-scale consequences of cumulative headwater alteration. Downstream eutrophication and coastal hypoxia result, in part, from agricultural practices that alter headwaters and wetlands while increasing nutrient runoff. Extensive headwater alteration is also expected to lower secondary productivity of river systems by reducing stream-system length and trophic subsidies to downstream river segments, affecting aquatic communities and terrestrial wildlife that utilize aquatic resources. Reduced viability of freshwater biota may occur with cumulative headwater alteration, including for species that occupy a range of stream sizes but for which headwater streams diversify the network of interconnected populations or enhance survival for particular life stages. Developing a more predictive understanding of ecological patterns that may emerge on regional scales as a result of headwater alterations will require studies focused on components and pathways that connect headwaters to river, coastal and

  9. Solar cell grid patterns

    NASA Technical Reports Server (NTRS)

    Yasui, R. K.; Berman, P. A. (Inventor)

    1976-01-01

    A grid pattern is described for a solar cell of the type which includes a semiconductive layer doped to a first polarity and a top counter-doped layer. The grid pattern comprises a plurality of concentric conductive grids of selected geometric shapes which are centered about the center of the exposed active surface of the counter-doped layer. Connected to the grids is one or more conductors which extend to the cell's periphery. For the pattern area, the grids and conductors are arranged in the pattern to minimize the maximum distance which any injected majority carriers have to travel to reach any of the grids or conductors. The pattern has a multiaxes symmetry with respect to the cell center to minimize the maximum temperature differentials between points on the cell surface and to provide a more uniform temperature distribution across the cell face.

  10. PV based converter with integrated charger for DC micro-grid applications

    NASA Astrophysics Data System (ADS)

    Salve, Rima

    This thesis presents a converter topology for photovoltaic panels. This topology minimizes the number of switching devices used thereby reducing power losses that arise from high frequency switching operations. The control strategy is implemented using a simple microcontroller that implements the proportional plus integral control. All the control loops are closed feedback loops hence minimizing error instantaneously and adjusting efficiently to system variations. The energy management between three components, namely, the photovoltaic panel, a battery and a DC link for a microgrid is shown distributed over three modes. These modes are dependent on the irradiance from the sunlight. All three modes are simulated. The maximum power point tracking of the system plays a crutial role in this configuration as it is one of the main challenge tackled by the control system. Various methods of MPPT are discussed and the Perturb and Observe method is employed and is described in detail. Experimental results are shown for the maximum power point tracking of this system with a scaled down version of the panel's actual capability.

  11. A flow integrated DSD hydrodynamics strategy for computing the motion of detonation of insensitive high explosives on an Eulerian grid

    SciTech Connect

    Short, Mark; Aslam, Tariq D

    2010-01-01

    The detonation structure in many insensitive high explosives consists of two temporally disparate zones of heat release. In PBX 9502, there is a fast reaction zone ({approx} 25 ns) during which reactants are converted to gaseous products and small carbon clusters, followed by a slower regime ({approx} 250 ns) of carbon coagulation. A hybrid approach for determining the propagation of two-stage heat release detonations has been developed that utilizes a detonation shock dynamics (DSD) based strategy for the fast reaction zone with a direct hydrodynamic simulation of the flow in the slow zone. Unlike a standard DSD/programmed bum formulation, the evolution of the fast zone DSD-like surface is coupled to the flow in the slow reaction zone. We have termed this formulation flow integrated detonation shock dynamics (FIDSD). The purpose of the present paper is to show how the FIDSD formulation can be applied to detonation propagation on an Eulerian grid using an algorithm based on level set interface tracking and a ghost fluid approach.

  12. Integration of ESPAS, IUGONET and ISDC: Connection of domain and terminological ontologies

    NASA Astrophysics Data System (ADS)

    Ritschel, Bernd; Borchert, Friederike; Neher, Günther; Schildbach, Susanne; Kneitschel, Gregor; Iyemori, Toshihiko; Yatagai, Akiyo; Koyama, Yukinobu; Hori, Tomoaki; Lowe, Dominic; Galkin, Ivan; King, Todd

    2013-04-01

    ESPAS, IUGONET and ISDC are e-infrastructure projects covering the near-earth space domain. The corresponding data management systems provide analogous in-situ and remote measured data from ground- and space-based instruments as well as appropriate context data. An integrated use of this data would strongly enhance the near-earth space science research potential. Different data models and technical realizations hinder the direct interaction of the referred data managements systems. Both the adoption of domain specific data models and the shared use of established terminologies are methods for the connection of data management systems. A first and promising approach of an integrated use of data is the design and common use of a terminology for the annotation and retrieval of content and context. The draft design of this terminology is based on the SPASE vocabulary modeled as terminological SKOS ontology. The terms of this vocabulary are derived from the "allowed values" of the SPASE data model enhanced by contributions from space physics science teams working with this specific data. Domain specific and cross-domain extensions of the SPASE vocabulary are realized by the merging of GCMD science keywords and GEMET thesaurus. Another focus in this context is the development of a new semantic-web-based ISDC infrastructure and the merging of the ISDC domain ontology with the SPASE vocabulary. The challenges and lessons learned during the design and integration of geoscience-related domain and terminological ontologies are the related topics of this paper.

  13. Integrated specialty service readiness in health reform: connections in haemophilia comprehensive care.

    PubMed

    Pritchard, A M; Page, D

    2008-05-01

    The World Health Organization (WHO) has identified primary healthcare reform as a global priority whereby innovative practice changes are directed at improving health. This transformation to health reform in haemophilia service requires clarification of comprehensive care to reflect the WHO definition of health and key elements of primary healthcare reform. While comprehensive care supports effective healthcare delivery, comprehensive care must also be regarded beyond immediate patient management to reflect the broader system purpose in the care continuum with institutions, community agencies and government. Furthermore, health reform may be facilitated through integrated service delivery (ISD). ISD in specialty haemophilia care has the potential to reduce repetition of assessments, enhance care plan communication between providers and families, provide 24-h access to care, improve information availability regarding care quality and outcomes, consolidate access for multiple healthcare encounters and facilitate family self-efficacy and autonomy [1]. Three core aspects of ISD have been distinguished: clinical integration, information management and technology and vertical integration in local communities [2]. Selected examples taken from Canadian haemophilia comprehensive care illustrate how practice innovations are bridged with a broader system level approach and may support initiatives in other contexts. These innovations are thought to indicate readiness regarding ISD. Reflecting on the existing capacity of haemophilia comprehensive care teams will assist providers to connect and direct their existing strengths towards ISD and health reform. PMID:18331561

  14. The GridKa Tier-1 Computing Center within the ALICE Grid Framework

    NASA Astrophysics Data System (ADS)

    Park, WooJin J.; Christopher, Jung; Heiss, Andreas; Petzold, Andreas; Schwarz, Kilian

    2014-06-01

    The GridKa computing center, hosted by Steinbuch Centre for Computing at the Karlsruhe Institute for Technology (KIT) in Germany, is serving as the largest Tier-1 center used by the ALICE collaboration at the LHC. In 2013, GridKa provides 30k HEPSPEC06, 2.7 PB of disk space, and 5.25 PB of tape storage to ALICE. The 10Gbit/s network connections from GridKa to CERN, several Tier-1 centers and the general purpose network are used by ALICE intensively. In 2012 a total amount of ~1 PB was transferred to and from GridKa. As Grid framework, AliEn (ALICE Environment) is being used to access the resources, and various monitoring tools including the MonALISA (MONitoring Agent using a Large Integrated Services Architecture) are always running to alert in case of any problem. GridKa on-call engineers provide 24/7 support to guarantee minimal loss of availability of computing and storage resources in case of hardware or software problems. We introduce the GridKa Tier-1 center from the viewpoint of ALICE services.

  15. Integrated landscape-based approach of remote sensing, GIS, and physical modelling to study the hydrological connectivity of wetlands to the downstream water: progress and challenge

    NASA Astrophysics Data System (ADS)

    Yeo, I. Y.

    2015-12-01

    We report the recent progress on our effort to improve the mapping of wetland dynamics and the modelling of its functioning and hydrological connection to the downstream waters. Our study focused on the Coastal Plain of the Chesapeake Bay Watershed (CBW), the Delmarva Peninsula, where the most of wetlands in CBW are densely distributed. The wetland ecosystem plays crucial roles in improving water quality and ecological integrity for the downstream waters and the Chesapeake Bay, and headwater wetlands in the region, such as Delmarva Bay, are now subject to the legal protection under the Clean Water Rules. We developed new wetland maps using time series Landsat images and a highly accurate LiDAR map over last 30 years. These maps show the changes in surface water fraction at a 30-m grid cell at annual time scale. Using GIS, we analyse these maps to characterize changing dynamics of wetland inundation due to the physical environmental factors (e.g., weather variability, tide) and assessed the hydrological connection of wetlands to the downstream water at the watershed scale. Focusing on the two adjacent watersheds in the upper region of the Choptank River Basin, we study how wetland inundation dynamics and the hydrologic linkage of wetlands to downstream water would vary by the local hydrogeological setting and attempt to identify the key landscape factors affecting the wetland ecosystems and functioning. We then discuss the potential of using remote sensing products to improve the physical modelling of wetlands from our experience with SWAT (Soil and Water Assessment Tool).

  16. Identification of the minimal connected network of transcription factors by transcriptomic and genomic data integration.

    PubMed

    Essaghir, Ahmed

    2014-01-01

    Thanks to high-throughput experiments, biological conditions can be investigated at both the entire genomic and transcriptomic levels. In addition, protein-protein interaction (PPI) data are widely available for well-studied organisms, such as human. In this chapter, we will present an integrative approach that makes use of these data to find the PPI module involving the key regulated transcription factors shared by a number of given conditions. These conditions could be for instance different cancer types. Briefly, for the studied conditions, we need to identify commonly affected chromosomal regions subjected to copy number alterations together with the identification of differentially expressed list of genes in each condition. Transcription factor activity will be inferred from these regulated gene lists. Then, we will define TFs, for which the activity could be explained by an associative effect of both loci copy number alteration and gene expression levels of their coding genes. PPI networks could be mined, afterwards, using appropriate algorithms to find the significant module that connect those TFs together. This module could be viewed as the minimal connected network of TFs, the regulation of which is shared between the investigated conditions.

  17. Mid-Task Break Improves Global Integration of Functional Connectivity in Lower Alpha Band

    PubMed Central

    Li, Junhua; Lim, Julian; Chen, Yu; Wong, Kianfoong; Thakor, Nitish; Bezerianos, Anastasios; Sun, Yu

    2016-01-01

    Numerous efforts have been devoted to revealing neurophysiological mechanisms of mental fatigue, aiming to find an effective way to reduce the undesirable fatigue-related outcomes. Until recently, mental fatigue is thought to be related to functional dysconnectivity among brain regions. However, the topological representation of brain functional connectivity altered by mental fatigue is only beginning to be revealed. In the current study, we applied a graph theoretical approach to analyse such topological alterations in the lower alpha band (8~10 Hz) of EEG data from 20 subjects undergoing a two-session experiment, in which one session includes four successive blocks with visual oddball tasks (session 1) whereas a mid-task break was introduced in the middle of four task blocks in the other session (session 2). Phase lag index (PLI) was then employed to measure functional connectivity strengths for all pairs of EEG channels. Behavior and connectivity maps were compared between the first and last task blocks in both sessions. Inverse efficiency scores (IES = reaction time/response accuracy) were significantly increased in the last task block, showing a clear effect of time-on-task in participants. Furthermore, a significant block-by-session interaction was revealed in the IES, suggesting the effectiveness of the mid-task break on maintaining task performance. More importantly, a significant session-independent deficit of global integration and an increase of local segregation were found in the last task block across both sessions, providing further support for the presence of a reshaped topology in functional brain connectivity networks under fatigue state. Moreover, a significant block-by-session interaction was revealed in the characteristic path length, small-worldness, and global efficiency, attributing to the significantly disrupted network topology in session 1 in comparison of the maintained network structure in session 2. Specifically, we found increased

  18. Mid-Task Break Improves Global Integration of Functional Connectivity in Lower Alpha Band.

    PubMed

    Li, Junhua; Lim, Julian; Chen, Yu; Wong, Kianfoong; Thakor, Nitish; Bezerianos, Anastasios; Sun, Yu

    2016-01-01

    Numerous efforts have been devoted to revealing neurophysiological mechanisms of mental fatigue, aiming to find an effective way to reduce the undesirable fatigue-related outcomes. Until recently, mental fatigue is thought to be related to functional dysconnectivity among brain regions. However, the topological representation of brain functional connectivity altered by mental fatigue is only beginning to be revealed. In the current study, we applied a graph theoretical approach to analyse such topological alterations in the lower alpha band (8~10 Hz) of EEG data from 20 subjects undergoing a two-session experiment, in which one session includes four successive blocks with visual oddball tasks (session 1) whereas a mid-task break was introduced in the middle of four task blocks in the other session (session 2). Phase lag index (PLI) was then employed to measure functional connectivity strengths for all pairs of EEG channels. Behavior and connectivity maps were compared between the first and last task blocks in both sessions. Inverse efficiency scores (IES = reaction time/response accuracy) were significantly increased in the last task block, showing a clear effect of time-on-task in participants. Furthermore, a significant block-by-session interaction was revealed in the IES, suggesting the effectiveness of the mid-task break on maintaining task performance. More importantly, a significant session-independent deficit of global integration and an increase of local segregation were found in the last task block across both sessions, providing further support for the presence of a reshaped topology in functional brain connectivity networks under fatigue state. Moreover, a significant block-by-session interaction was revealed in the characteristic path length, small-worldness, and global efficiency, attributing to the significantly disrupted network topology in session 1 in comparison of the maintained network structure in session 2. Specifically, we found increased

  19. A grid amplifier

    NASA Technical Reports Server (NTRS)

    Kim, Moonil; Weikle, Robert M., II; Hacker, Jonathan B.; Delisio, Michael P.; Rutledge, David B.; Rosenberg, James J.; Smith, R. P.

    1991-01-01

    A 50-MESFET grid amplifier is reported that has a gain of 11 dB at 3.3 GHz. The grid isolates the input from the output by using vertical polarization for the input beam and horizontal polarization for the transmitted output beam. The grid unit cell is a two-MESFET differential amplifier. A simple calibration procedure allows the gain to be calculated from a relative power measurement. This grid is a hybrid circuit, but the structure is suitable for fabrication as a monolithic wafer-scale integrated circuit, particularly at millimeter wavelengths.

  20. Connecting the dots: how local structure affects global integration in infants.

    PubMed

    Palomares, Melanie; Pettet, Mark; Vildavski, Vladimir; Hou, Chuan; Norcia, Anthony

    2010-07-01

    Glass patterns are moirés created from a sparse random-dot field paired with its spatially shifted copy. Because discrimination of these patterns is not based on local features, they have been used extensively to study global integration processes. Here, we investigated whether 4- to 5.5-month-old infants are sensitive to the global structure of Glass patterns by measuring visual-evoked potentials. Although we found strong responses to the appearance of the constituent dots, we found sensitivity to the global structure of the Glass patterns in the infants only over a very limited range of spatial separation. In contrast, we observed robust responses in the infants when we connected the dot pairs of the Glass pattern with lines. Moreover, both infants and adults showed differential responses to exchanges between line patterns portraying different global structures. A control study varying luminance contrast in adults suggests that infant sensitivity to global structure is not primarily limited by reduced element visibility. Together our results suggest that the insensitivity to structure in conventional Glass patterns is due to inefficiencies in extracting the local orientation cues generated by the dot pairs. Once the local orientations are made unambiguous or when the interpolation span is small, infants can integrate these signals over the image.

  1. Subdivision based isogeometric analysis technique for electric field integral equations for simply connected structures

    NASA Astrophysics Data System (ADS)

    Li, Jie; Dault, Daniel; Liu, Beibei; Tong, Yiying; Shanker, Balasubramaniam

    2016-08-01

    The analysis of electromagnetic scattering has long been performed on a discrete representation of the geometry. This representation is typically continuous but not differentiable. The need to define physical quantities on this geometric representation has led to development of sets of basis functions that need to satisfy constraints at the boundaries of the elements/tessellations (viz., continuity of normal or tangential components across element boundaries). For electromagnetics, these result in either curl/div-conforming basis sets. The geometric representation used for analysis is in stark contrast with that used for design, wherein the surface representation is higher order differentiable. Using this representation for both geometry and physics on geometry has several advantages, and is elucidated in Hughes et al. (2005) [7]. Until now, a bulk of the literature on isogeometric methods have been limited to solid mechanics, with some effort to create NURBS based basis functions for electromagnetic analysis. In this paper, we present the first complete isogeometry solution methodology for the electric field integral equation as applied to simply connected structures. This paper systematically proceeds through surface representation using subdivision, definition of vector basis functions on this surface, to fidelity in the solution of integral equations. We also present techniques to stabilize the solution at low frequencies, and impose a Calderón preconditioner. Several results presented serve to validate the proposed approach as well as demonstrate some of its capabilities.

  2. How does the modular organization of entorhinal grid cells develop?

    PubMed Central

    Pilly, Praveen K.; Grossberg, Stephen

    2014-01-01

    The entorhinal-hippocampal system plays a crucial role in spatial cognition and navigation. Since the discovery of grid cells in layer II of medial entorhinal cortex (MEC), several types of models have been proposed to explain their development and operation; namely, continuous attractor network models, oscillatory interference models, and self-organizing map (SOM) models. Recent experiments revealing the in vivo intracellular signatures of grid cells (Domnisoru et al., 2013; Schmidt-Heiber and Hausser, 2013), the primarily inhibitory recurrent connectivity of grid cells (Couey et al., 2013; Pastoll et al., 2013), and the topographic organization of grid cells within anatomically overlapping modules of multiple spatial scales along the dorsoventral axis of MEC (Stensola et al., 2012) provide strong constraints and challenges to existing grid cell models. This article provides a computational explanation for how MEC cells can emerge through learning with grid cell properties in modular structures. Within this SOM model, grid cells with different rates of temporal integration learn modular properties with different spatial scales. Model grid cells learn in response to inputs from multiple scales of directionally-selective stripe cells (Krupic et al., 2012; Mhatre et al., 2012) that perform path integration of the linear velocities that are experienced during navigation. Slower rates of grid cell temporal integration support learned associations with stripe cells of larger scales. The explanatory and predictive capabilities of the three types of grid cell models are comparatively analyzed in light of recent data to illustrate how the SOM model overcomes problems that other types of models have not yet handled. PMID:24917799

  3. Space Development Grid Portal

    NASA Technical Reports Server (NTRS)

    Vaziri, Arsi

    2004-01-01

    This viewgraph presentation provides information on the development of a portal to provide secure and distributed grid computing for Payload Operations Integrated Center and Mission Control Center ground services.

  4. Integrating Oil and Gas Measurement Data to Estimate Spatially-Gridded Methane Emissions in the Barnett Shale

    NASA Astrophysics Data System (ADS)

    Lyon, D. R.; Zavala Araiza, D.; Alvarez, R.; Harriss, R. C.; Palacios, V.; Lan, X.; Talbot, R. W.; Shepson, P. B.; Lavoie, T. N.; Yacovitch, T. I.; Herndon, S. C.; Marchese, A.; Zimmerle, D.; Robinson, A. L.; Hamburg, S.

    2015-12-01

    In October 2013, a dozen research teams measured methane emissions from oil and gas (O&G) and other sources in the Barnett Shale region of Texas at multiple scales ranging from bottom-up component measurements to top-down regional emission measurements. This work integrates ground- and aircraft-based measurements of site-level emissions from the campaign and a recent national study of gathering and processing facilities to construct a spatially resolved emission inventory for the Barnett Shale. Spatially referenced activity data including O&G site locations were obtained from multiple databases. O&G site emission factors were estimated with two-step Monte Carlo simulations that integrated emission rates from unbiased datasets with higher measurements obtained with targeted sampling. Emissions from other fossil and biogenic sources were estimated from reported emissions data or published emission factors. We constructed a 4 km x 4 km gridded emission inventory to estimate emissions by source category in the 25-county Barnett region. Total methane emissions in October 2013 were estimated to be 72.3 (+10.1/-8.9) Mg CH4 h-1 with 46.2 (+7.9/-6.2) from O&G sources. Fat-tail sites, which were defined as emission rates above the unbiased sampling distributions, accounted for 19% of O&G emissions but less than 2% of sites. In comparison to alternative estimates of O&G emissions based on the United States Environmental Protection Agency Greenhouse Gas Inventory, EPA Greenhouse Gas Reporting Program, and Emissions Database for Global Atmospheric Research, our custom inventory was higher by factors of 1.5, 2.7, and 4.3, respectively, similar to published ratios of top-down and bottom up estimates. Our custom inventory was higher than alternatives primarily due to more complete activity data and the inclusion of fat-tail site emissions. Gathering facilities, which accounted for 40% of our O&G emission estimate, had the largest difference from alternative inventories.

  5. ProcessGene-Connect: SOA Integration between Business Process Models and Enactment Transactions of Enterprise Software Systems

    NASA Astrophysics Data System (ADS)

    Wasser, Avi; Lincoln, Maya

    In recent years, both practitioners and applied researchers have become increasingly interested in methods for integrating business process models and enterprise software systems through the deployment of enabling middleware. Integrative BPM research has been mainly focusing on the conversion of workflow notations into enacted application procedures, and less effort has been invested in enhancing the connectivity between design level, non-workflow business process models and related enactment systems such as: ERP, SCM and CRM. This type of integration is useful at several stages of an IT system lifecycle, from design and implementation through change management, upgrades and rollout. The paper presents an integration method that utilizes SOA for connecting business process models with corresponding enterprise software systems. The method is then demonstrated through an Oracle E-Business Suite procurement process and its ERP transactions.

  6. Service-aware resources integrated resilience for software defined data center networking based on IP over Flexi-Grid optical networks

    NASA Astrophysics Data System (ADS)

    Yang, Hui; Zhang, Jie; Zhao, Yongli; Cheng, Lei; Wu, Jialin; Ji, Yuefeng; Han, Jianrui; Lin, Yi; Lee, Young

    2015-01-01

    Due to the performance guarantee of low delay, huge bandwidth and high reliability at a low cost, IP over Flexi-Grid optical network is a very promising networking architecture applied to the interconnection of geographically distributed data centers. It can enable efficient resource utilization and support heterogeneous bandwidth demands in cost-effective, highly-available and energy-effective manner. In case of edge Flexi-Grid optical network node failure, to ensure a high-level quality of service (QoS) for user request after the failure becomes a research focus. In this paper, we propose a novel service-aware resources integrated resilience (SA-RIR) scheme for data center services in software defined data center networking architecture based on IP over Flexi-Grid optical networks. Different from previous works which restore the services just exploiting the optical stratum, the proposed scheme provides the resilience using the multiple stratums resources in case of the edge optical node failure. We quantitatively evaluate the feasibility and performances through the simulation under heavy traffic load scenario in terms of path blocking probability, path resilience latency and resource occupation rate with different failure rates. Simulation results show that, the SA-RIR scheme can enable joint optimization of IP network, Flexi-Grid optical network and data center application stratum resources, and enhance the data center service resilience responsiveness to the dynamic end-to-end demands.

  7. Integrating Scientific Content with Context to Connect Educators with the Complexities and Consequences of Climate Change

    NASA Astrophysics Data System (ADS)

    Low, R.; Gosselin, D. C.; Oglesby, R. J.; Larson-Miller, C.; Thomas, J.; Mawalagedara, R.

    2011-12-01

    Over the past three years the Nebraska Earth Systems Education Network has designed professional development opportunities for K-12 and extension educators that integrates scientific content into the context of helping educators connect society with the complexities and consequences of climate change. Our professional development approach uses learner-, knowledge-, assessment-, and community-centered strategies to achieve our long-term goal: collaboration of scientists, educators and learners to foster civic literacy about climate change. Two NASA-funded projects, Global Climate Change Literacy for Educators (GCCE, 2009-2012), and the Educators Climatologists Learning Community (ECLC, 2011-2013), have provided the mechanism to provide teachers with scientifically sound and pedagogically relevant educational materials to improve climate and Earth systems literacy among educators. The primary product of the GCCE program is a 16-week, online, distance-delivered, asynchronous course entitled, Laboratory Earth: Human Dimensions of Climate Change. This course consists of four, four-week modules that integrate climate literacy, Earth Systems concepts, and pedagogy focused on active learning processes, building community, action research, and students' sense of place to promote action at the local level to address the challenges of climate change. Overall, the Community of Inquiry Survey (COI) indicated the course was effective in teaching content, developing a community of learners, and engaging students in experiences designed to develop content knowledge. A pre- and post- course Wilcoxan Signed Ranks Test indicated there was a statistically significant increase in participant's beliefs about their personal science teaching efficacy. Qualitative data from concept maps and content mastery assignments support a positive impact on teachers' content knowledge and classroom practice. Service Learning units seemed tohelp teachers connect course learning to their classroom

  8. Grid-Tied Photovoltaic Power System

    NASA Technical Reports Server (NTRS)

    Eichenberg, Dennis J.

    2011-01-01

    A grid-tied photovoltaic (PV) power system is connected directly to the utility distribution grid. Facility power can be obtained from the utility system as normal. The PV system is synchronized with the utility system to provide power for the facility, and excess power is provided to the utility. Operating costs of a PV power system are low compared to conventional power technologies. This method can displace the highest-cost electricity during times of peak demand in most climatic regions, and thus reduce grid loading. Net metering is often used, in which independent power producers such as PV power systems are connected to the utility grid via the customers main service panels and meters. When the PV power system is generating more power than required at that location, the excess power is provided to the utility grid. The customer pays the net of the power purchased when the on-site power demand is greater than the onsite power production, and the excess power is returned to the utility grid. Power generated by the PV system reduces utility demand, and the surplus power aids the community. Modern PV panels are readily available, reliable, efficient, and economical, with a life expectancy of at least 25 years. Modern electronics have been the enabling technology behind grid-tied power systems, making them safe, reliable, efficient, and economical with a life expectancy equal to the modern PV panels. The grid-tied PV power system was successfully designed and developed, and this served to validate the basic principles developed, and the theoretical work that was performed. Grid-tied PV power systems are reliable, maintenance- free, long-life power systems, and are of significant value to NASA and the community. Of particular value are the analytical tools and capabilities that have been successfully developed. Performance predictions can be made confidently for grid-tied PV systems of various scales. The work was done under the NASA Hybrid Power Management (HPM

  9. Geological applications of automatic grid generation tools for finite elements applied to porous flow modeling

    SciTech Connect

    Gable, C.W.; Trease, H.E.; Cherry, T.A.

    1996-04-01

    The construction of grids that accurately reflect geologic structure and stratigraphy for computational flow and transport models poses a formidable task. Even with a complete understanding of stratigraphy, material properties, boundary and initial conditions, the task of incorporating data into a numerical model can be difficult and time consuming. Furthermore, most tools available for representing complex geologic surfaces and volumes are not designed for producing optimal grids for flow and transport computation. We have developed a modeling tool, GEOMESH, for automating finite element grid generation that maintains the geometric integrity of geologic structure and stratigraphy. The method produces an optimal (Delaunay) tetrahedral grid that can be used for flow and transport computations. The process of developing a flow and transport model can be divided into three parts: (1) Developing accurate conceptual models inclusive of geologic interpretation, material characterization and construction of a stratigraphic and hydrostratigraphic framework model, (2) Building and initializing computational frameworks; grid generation, boundary and initial conditions, (3) Computational physics models of flow and transport. Process (1) and (3) have received considerable attention whereas (2) has not. This work concentrates on grid generation and its connections to geologic characterization and process modeling. Applications of GEOMESH illustrate grid generation for two dimensional cross sections, three dimensional regional models, and adaptive grid refinement in three dimensions. Examples of grid representation of wells and tunnels with GEOMESH can be found in Cherry et al. The resulting grid can be utilized by unstructured finite element or integrated finite difference models.

  10. Oh, Deer!: Predator and Prey Relationships--Students Make Natural Connections through the Integration of Mathematics and Science

    ERIC Educational Resources Information Center

    Reeder, Stacy; Moseley, Christine

    2006-01-01

    This article describes an activity that integrates both mathematics and science while inviting students to make connections between the two and learn significant concepts in a meaningful way. Students work within the real-world context of wildlife population scenarios to make predictions, test their hypotheses, and determine and construct graphs…

  11. A Model for Integration of Content, Concepts, and Context within Separate Courses: Making Explicit the Connections among Discipline

    ERIC Educational Resources Information Center

    Blumberg, Phyllis; Mostrom, Alison M.; Bendl, Barbara; Kimchuk, Amy; Wolbach, Kevin

    2005-01-01

    We developed, piloted, and evaluated a successful model for integrating other disciplinary perspectives while learning a specific discipline. Faculty who taught first-year biology and mathematics courses produced examples of how these disciplines complement each other. These faculty presented students with the connecting threads that integrate…

  12. On the application of Chimera/unstructured hybrid grids for conjugate heat transfer

    NASA Technical Reports Server (NTRS)

    Kao, Kai-Hsiung; Liou, Meng-Sing

    1995-01-01

    A hybrid grid system that combines the Chimera overset grid scheme and an unstructured grid method is developed to study fluid flow and heat transfer problems. With the proposed method, the solid structural region, in which only the heat conduction is considered, can be easily represented using an unstructured grid method. As for the fluid flow region external to the solid material, the Chimera overset grid scheme has been shown to be very flexible and efficient in resolving complex configurations. The numerical analyses require the flow field solution and material thermal response to be obtained simultaneously. A continuous transfer of temperature and heat flux is specified at the interface, which connects the solid structure and the fluid flow as an integral system. Numerical results are compared with analytical and experimental data for a flat plate and a C3X cooled turbine cascade. A simplified drum-disk system is also simulated to show the effectiveness of this hybrid grid system.

  13. A Study on Dumping Power Flow Fluctuation at Grid-Connection Point of Residential Micro-Grid with Clustered Photovoltaic Power Generation Systems Considering Difference in Solar Irradiance Patterns in Urban Districts

    NASA Astrophysics Data System (ADS)

    Kato, Takeyoshi; Yamawaki, Hiroshi; Suzuoki, Yasuo

    Power output fluctuation of photovoltaic power generation systems (PVSs) may cause negative impacts on the existing electric power system when the penetration of PVSs is quite large. A micro-grid consisting of clustered PVSs and a battery system would be one of the promising measures against negative impacts of clustered PVSs, while the capacity of battery system should be reduced as much as possible from the economic point of view. Because of the difference in output fluctuation among PVSs in the various locations, the total output fluctuations of PVSs would be relaxed due to the so-called “smoothing-effect”. By using data on solar irradiance simultaneously observed at five points, this study evaluates the total output fluctuation of several micro-grids and the required capacity of battery system, taking the smoothing effect into account. The main results are as follows. The balancing control is accomplished with the acceptable error by using the small capacity of battery system, while small output fluctuation still remains in each micro-grid. In such the situation, because the total fluctuation of five micro-grids is not so large, the acceptable error in balancing control can be increased by a few percentages, resulting in reduction in the required maximum power of battery system by a few ten percentages.

  14. Wind Energy Management System Integration Project Incorporating Wind Generation and Load Forecast Uncertainties into Power Grid Operations

    SciTech Connect

    Makarov, Yuri V.; Huang, Zhenyu; Etingov, Pavel V.; Ma, Jian; Guttromson, Ross T.; Subbarao, Krishnappa; Chakrabarti, Bhujanga B.

    2010-09-01

    features make this work a significant step forward toward the objective of incorporating of wind, solar, load, and other uncertainties into power system operations. In this report, a new methodology to predict the uncertainty ranges for the required balancing capacity, ramping capability and ramp duration is presented. Uncertainties created by system load forecast errors, wind and solar forecast errors, generation forced outages are taken into account. The uncertainty ranges are evaluated for different confidence levels of having the actual generation requirements within the corresponding limits. The methodology helps to identify system balancing reserve requirement based on a desired system performance levels, identify system “breaking points”, where the generation system becomes unable to follow the generation requirement curve with the user-specified probability level, and determine the time remaining to these potential events. The approach includes three stages: statistical and actual data acquisition, statistical analysis of retrospective information, and prediction of future grid balancing requirements for specified time horizons and confidence intervals. Assessment of the capacity and ramping requirements is performed using a specially developed probabilistic algorithm based on a histogram analysis incorporating all sources of uncertainty and parameters of a continuous (wind forecast and load forecast errors) and discrete (forced generator outages and failures to start up) nature. Preliminary simulations using California Independent System Operator (California ISO) real life data have shown the effectiveness of the proposed approach. A tool developed based on the new methodology described in this report will be integrated with the California ISO systems. Contractual work is currently in place to integrate the tool with the AREVA EMS system.

  15. Integrating land management into Earth system models: the importance of land use transitions at sub-grid-scale

    NASA Astrophysics Data System (ADS)

    Pongratz, Julia; Wilkenskjeld, Stiig; Kloster, Silvia; Reick, Christian

    2014-05-01

    Recent studies indicate that changes in surface climate and carbon fluxes caused by land management (i.e., modifications of vegetation structure without changing the type of land cover) can be as large as those caused by land cover change. Further, such effects may occur on substantial areas: while about one quarter of the land surface has undergone land cover change, another fifty percent are managed. This calls for integration of management processes in Earth system models (ESMs). This integration increases the importance of awareness and agreement on how to diagnose effects of land use in ESMs to avoid additional model spread and thus unnecessary uncertainties in carbon budget estimates. Process understanding of management effects, their model implementation, as well as data availability on management type and extent pose challenges. In this respect, a significant step forward has been done in the framework of the current IPCC's CMIP5 simulations (Coupled Model Intercomparison Project Phase 5): The climate simulations were driven with the same harmonized land use dataset that, different from most datasets commonly used before, included information on two important types of management: wood harvest and shifting cultivation. However, these new aspects were employed by only part of the CMIP5 models, while most models continued to use the associated land cover maps. Here, we explore the consequences for the carbon cycle of including subgrid-scale land transformations ("gross transitions"), such as shifting cultivation, as example of the current state of implementation of land management in ESMs. Accounting for gross transitions is expected to increase land use emissions because it represents simultaneous clearing and regrowth of natural vegetation in different parts of the grid cell, reducing standing carbon stocks. This process cannot be captured by prescribing land cover maps ("net transitions"). Using the MPI-ESM we find that ignoring gross transitions

  16. Utility-Scale Solar Power Converter: Agile Direct Grid Connect Medium Voltage 4.7-13.8 kV Power Converter for PV Applications Utilizing Wide Band Gap Devices

    SciTech Connect

    2012-01-25

    Solar ADEPT Project: Satcon is developing a compact, lightweight power conversion device that is capable of taking utility-scale solar power and outputting it directly into the electric utility grid at distribution voltage levels—eliminating the need for large transformers. Transformers “step up” the voltage of the power that is generated by a solar power system so it can be efficiently transported through transmission lines and eventually “stepped down” to usable voltages before it enters homes and businesses. Power companies step up the voltage because less electricity is lost along transmission lines when the voltage is high and current is low. Satcon’s new power conversion devices will eliminate these heavy transformers and connect a utility-scale solar power system directly to the grid. Satcon’s modular devices are designed to ensure reliability—if one device fails it can be bypassed and the system can continue to run.

  17. Data Grid Implementations

    SciTech Connect

    Moore, Reagan W.; Studham, Ronald S.; Rajasekar, Arcot; Watson, Chip; Stockinger, Heinz; Kunszt, Peter; Charlie Catlett and Ian Foster

    2002-02-27

    Data grids link distributed, heterogeneous storage resources into a coherent data management system. From a user perspective, the data grid provides a uniform name space across the underlying storage systems, while supporting retrieval and storage of files. In the high energy physics community, at least six data grids have been implemented for the storage and distribution of experimental data. Data grids are also being used to support projects as diverse as digital libraries (National Library of Medicine Visible Embryo project), federation of multiple astronomy sky surveys (NSF National Virtual Observatory project), and integration of distributed data sets (Long Term Ecological Reserve). Data grids also form the core interoperability mechanisms for creating persistent archives, in which data collections are migrated to new technologies over time. The ability to provide a uniform name space across multiple administration domains is becoming a critical component of national-scale, collaborative projects.

  18. Hierarchical mechanics of connective tissues: integrating insights from nano to macroscopic studies.

    PubMed

    Gohl, Kheng Lim; Listrat, Anne; Béchet, Daniel

    2014-10-01

    As the key component of the musculoskeletal system, the extracellular matrix of soft connective tissues such as ligaments and tendons is a biological example of fibre-reinforced composite but with a complex hierarchical architecture. To establish a comprehensive structure-function relationship at the respective levels (i.e., from molecule to tissue) of the hierarchical architecture is challenging and requires a multidisciplinary approach, involving the integration of findings from the fields of molecular biology, biochemistry, structural biology, materials science and biophysics. Accordingly, in recent years, some of these fields, namely structural biology, materials science and biophysics, have made significant progress in the microscale and nanoscale studies of extracellular matrix using new tools, such as microelectromechanical systems, optical tweezers and atomic force microscopy, complemented by new techniques in simultaneous imaging and mechanical testing and computer modelling. The intent of this paper is to review the key findings on the mechanical response of extracellular matrix at the respective levels of the hierarchical architecture. The main focus is on the structure and function--the findings are compared across the different levels to provide insights that support the goal of establishing a comprehensive structure-function relationship of extracellular matrix. For this purpose, the review is divided into two parts. The first part explores the features of key structural units of extracellular matrix, namely tropocollagen molecule (the lowest level), microfibril, collagen fibril, collagen fibre and fascicle. The second part examines the mechanics of the structural units at the respective levels. Finally a framework for extracellular matrix mechanics is proposed to support the goal to establish a comprehensive structure-function relationship. The framework describes the integration of the mechanisms of reinforcement by the structural units at the

  19. Hierarchical mechanics of connective tissues: integrating insights from nano to macroscopic studies.

    PubMed

    Gohl, Kheng Lim; Listrat, Anne; Béchet, Daniel

    2014-10-01

    As the key component of the musculoskeletal system, the extracellular matrix of soft connective tissues such as ligaments and tendons is a biological example of fibre-reinforced composite but with a complex hierarchical architecture. To establish a comprehensive structure-function relationship at the respective levels (i.e., from molecule to tissue) of the hierarchical architecture is challenging and requires a multidisciplinary approach, involving the integration of findings from the fields of molecular biology, biochemistry, structural biology, materials science and biophysics. Accordingly, in recent years, some of these fields, namely structural biology, materials science and biophysics, have made significant progress in the microscale and nanoscale studies of extracellular matrix using new tools, such as microelectromechanical systems, optical tweezers and atomic force microscopy, complemented by new techniques in simultaneous imaging and mechanical testing and computer modelling. The intent of this paper is to review the key findings on the mechanical response of extracellular matrix at the respective levels of the hierarchical architecture. The main focus is on the structure and function--the findings are compared across the different levels to provide insights that support the goal of establishing a comprehensive structure-function relationship of extracellular matrix. For this purpose, the review is divided into two parts. The first part explores the features of key structural units of extracellular matrix, namely tropocollagen molecule (the lowest level), microfibril, collagen fibril, collagen fibre and fascicle. The second part examines the mechanics of the structural units at the respective levels. Finally a framework for extracellular matrix mechanics is proposed to support the goal to establish a comprehensive structure-function relationship. The framework describes the integration of the mechanisms of reinforcement by the structural units at the

  20. PEV Integration with Renewables (Presentation)

    SciTech Connect

    Markel, T.

    2014-06-18

    This presentation discusses current research at NREL on integrating plug-in electric vehicles with the grid and using renewable energy to charge the grid. The Electric Vehicle Grid Integration (EVGI) and Integrated Network Testbed for Energy Grid Research and Technology Experimentation (INTEGRATE) are addressing the opportunities and technical requirements for vehicle grid integration that will increase marketability and lead to greater petroleum reduction.

  1. Connectivity, fish communities, and human impacts: An integrated river systems perspective

    EPA Science Inventory

    The role of connectivity between aquatic habitats in sustaining productive and healthy fish communities has become a key conservation concern. Changes in connectivity due to anthropogenic impacts can alter fish communities and put particular species at risk. In order to underst...

  2. A control volume method on an icosahedral grid for numerical integration of the shallow-water equations on the sphere

    SciTech Connect

    Chern, I-Liang

    1994-08-01

    Two versions of a control volume method on a symmetrized icosahedral grid are proposed for solving the shallow-water equations on a sphere. One version expresses of the equations in the 3-D Cartersian coordinate system, while the other expresses the equations in the northern/southern polar sterographic coordinate systems. The pole problem is avoided because of these expressions in both versions and the quasi-homogenity of the icosahedral grid. Truncation errors and convergence tests of the numerical gradient and divergent operators associated with this method are studied. A convergence tests of the numerical gradient and divergent operators associated with this method are studied. A convergence test for a steady zonal flow is demonstrated. Several simulations of Rossby-Haurwitz waves with various numbers are also performed.

  3. Resting state functional connectivity magnetic resonance imaging integrated with intraoperative neuronavigation for functional mapping after aborted awake craniotomy

    PubMed Central

    Batra, Prag; Bandt, S. Kathleen; Leuthardt, Eric C.

    2016-01-01

    Background: Awake craniotomy is currently the gold standard for aggressive tumor resections in eloquent cortex. However, a significant subset of patients is unable to tolerate this procedure, particularly the very young or old or those with psychiatric comorbidities, cardiopulmonary comorbidities, or obesity, among other conditions. In these cases, typical alternative procedures include biopsy alone or subtotal resection, both of which are associated with diminished surgical outcomes. Case Description: Here, we report the successful use of a preoperatively obtained resting state functional connectivity magnetic resonance imaging (MRI) integrated with intraoperative neuronavigation software in order to perform functional cortical mapping in the setting of an aborted awake craniotomy due to loss of airway. Conclusion: Resting state functional connectivity MRI integrated with intraoperative neuronavigation software can provide an alternative option for functional cortical mapping in the setting of an aborted awake craniotomy. PMID:26958419

  4. The connectivity of functional cores reveals different degrees of segregation and integration in the brain at rest.

    PubMed

    de Pasquale, Francesco; Sabatini, Umberto; Della Penna, Stefania; Sestieri, Carlo; Caravasso, Chiara Falletta; Formisano, Rita; Péran, Patrice

    2013-04-01

    The principles of functional specialization and integration in the resting brain are implemented in a complex system of specialized networks that share some degree of interaction. Recent studies have identified wider functional modules compared to previously defined networks and reported a small-world architecture of brain activity in which central nodes balance the pressure to evolve segregated pathways with the integration of local systems. The accurate identification of such central nodes is crucial but might be challenging for several reasons, e.g. inter-subject variability and physiological/pathological network plasticity, and recent works reported partially inconsistent results concerning the properties of these cortical hubs. Here, we applied a whole-brain data-driven approach to extract cortical functional cores and examined their connectivity from a resting state fMRI experiment on healthy subjects. Two main statistically significant cores, centered on the posterior cingulate cortex and the supplementary motor area, were extracted and their functional connectivity maps, thresholded at three statistical levels, revealed the presence of two complex systems. One system is consistent with the default mode network (DMN) and gradually connects to visual regions, the other centered on motor regions and gradually connects to more sensory-specific portions of cortex. These two large scale networks eventually converged to regions belonging to the medial aspect of the DMN, potentially allowing inter-network interactions. PMID:23220493

  5. The Exercising Brain: Changes in Functional Connectivity Induced by an Integrated Multimodal Cognitive and Whole-Body Coordination Training.

    PubMed

    Demirakca, Traute; Cardinale, Vita; Dehn, Sven; Ruf, Matthias; Ende, Gabriele

    2016-01-01

    This study investigated the impact of "life kinetik" training on brain plasticity in terms of an increased functional connectivity during resting-state functional magnetic resonance imaging (rs-fMRI). The training is an integrated multimodal training that combines motor and cognitive aspects and challenges the brain by introducing new and unfamiliar coordinative tasks. Twenty-one subjects completed at least 11 one-hour-per-week "life kinetik" training sessions in 13 weeks as well as before and after rs-fMRI scans. Additionally, 11 control subjects with 2 rs-fMRI scans were included. The CONN toolbox was used to conduct several seed-to-voxel analyses. We searched for functional connectivity increases between brain regions expected to be involved in the exercises. Connections to brain regions representing parts of the default mode network, such as medial frontal cortex and posterior cingulate cortex, did not change. Significant connectivity alterations occurred between the visual cortex and parts of the superior parietal area (BA7). Premotor area and cingulate gyrus were also affected. We can conclude that the constant challenge of unfamiliar combinations of coordination tasks, combined with visual perception and working memory demands, seems to induce brain plasticity expressed in enhanced connectivity strength of brain regions due to coactivation. PMID:26819776

  6. The Exercising Brain: Changes in Functional Connectivity Induced by an Integrated Multimodal Cognitive and Whole-Body Coordination Training.

    PubMed

    Demirakca, Traute; Cardinale, Vita; Dehn, Sven; Ruf, Matthias; Ende, Gabriele

    2016-01-01

    This study investigated the impact of "life kinetik" training on brain plasticity in terms of an increased functional connectivity during resting-state functional magnetic resonance imaging (rs-fMRI). The training is an integrated multimodal training that combines motor and cognitive aspects and challenges the brain by introducing new and unfamiliar coordinative tasks. Twenty-one subjects completed at least 11 one-hour-per-week "life kinetik" training sessions in 13 weeks as well as before and after rs-fMRI scans. Additionally, 11 control subjects with 2 rs-fMRI scans were included. The CONN toolbox was used to conduct several seed-to-voxel analyses. We searched for functional connectivity increases between brain regions expected to be involved in the exercises. Connections to brain regions representing parts of the default mode network, such as medial frontal cortex and posterior cingulate cortex, did not change. Significant connectivity alterations occurred between the visual cortex and parts of the superior parietal area (BA7). Premotor area and cingulate gyrus were also affected. We can conclude that the constant challenge of unfamiliar combinations of coordination tasks, combined with visual perception and working memory demands, seems to induce brain plasticity expressed in enhanced connectivity strength of brain regions due to coactivation.

  7. The Exercising Brain: Changes in Functional Connectivity Induced by an Integrated Multimodal Cognitive and Whole-Body Coordination Training

    PubMed Central

    Demirakca, Traute; Cardinale, Vita; Dehn, Sven; Ruf, Matthias; Ende, Gabriele

    2016-01-01

    This study investigated the impact of “life kinetik” training on brain plasticity in terms of an increased functional connectivity during resting-state functional magnetic resonance imaging (rs-fMRI). The training is an integrated multimodal training that combines motor and cognitive aspects and challenges the brain by introducing new and unfamiliar coordinative tasks. Twenty-one subjects completed at least 11 one-hour-per-week “life kinetik” training sessions in 13 weeks as well as before and after rs-fMRI scans. Additionally, 11 control subjects with 2 rs-fMRI scans were included. The CONN toolbox was used to conduct several seed-to-voxel analyses. We searched for functional connectivity increases between brain regions expected to be involved in the exercises. Connections to brain regions representing parts of the default mode network, such as medial frontal cortex and posterior cingulate cortex, did not change. Significant connectivity alterations occurred between the visual cortex and parts of the superior parietal area (BA7). Premotor area and cingulate gyrus were also affected. We can conclude that the constant challenge of unfamiliar combinations of coordination tasks, combined with visual perception and working memory demands, seems to induce brain plasticity expressed in enhanced connectivity strength of brain regions due to coactivation. PMID:26819776

  8. Integrating new satellite observations from SMAP and OCO-2 for analyzing terrestrial water and carbon connections

    NASA Astrophysics Data System (ADS)

    Kimball, J. S.; Stavros, N.; Schimel, D.

    2014-12-01

    The successful inauguration of both NASA OCO-2 (Orbiting Carbon Observatory 2) and SMAP (Soil Moisture Active Passive) missions, and continuing operations from other flagship Earth Observing systems (e.g. MODIS) provide new opportunities to improve understanding of global carbon and water cycle connections over land. Carbon and water cycles interact such that soil moisture and frozen temperatures constrain net ecosystem productivity and terrestrial sources and sinks for atmospheric CO2. OCO-2 and SMAP will have overlapping global observations beginning in 2015. The combined measurements from these sensors provide complimentary information linking top-down atmospheric CO2 measurements with bottom-up carbon fluxes and underlying environmental controls. SMAP will consist of a satellite L-band radar and radiometer suite designed for global monitoring of soil moisture and freeze-thaw dynamics. SMAP science objectives include improving understanding of processes linking terrestrial water, energy and carbon cycles, and quantifying the net carbon flux in boreal landscapes. SMAP products include model enhanced estimates of net ecosystem CO2 flux (NEE) and component carbon fluxes for productivity and respiration; targeted accuracy for NEE is defined at the level of tower (FLUXNET) eddy covariance measurement based CO2 fluxes. OCO-2 has similar carbon science objectives and complimentary observations to SMAP, including canopy fluorescence (SIF) and atmosphere total column CO2 concentrations (XCO2) derived with unprecedented sampling and precision. An initial framework for integrating and analyzing these data is presented in the context of planned post-launch field campaigns and community carbon model synthesis activities. Example research applications are presented using available satellite data prior to SMAP and OCO-2 operations. Activities include using SIF (a proxy for canopy photosynthesis) with MODIS FPAR and SMAP data to improve understanding of canopy structural and

  9. Human effects on ecological connectivity in aquatic ecosystems: Integrating scientific approaches to support management and mitigation.

    PubMed

    Crook, David A; Lowe, Winsor H; Allendorf, Frederick W; Erős, Tibor; Finn, Debra S; Gillanders, Bronwyn M; Hadwen, Wade L; Harrod, Chris; Hermoso, Virgilio; Jennings, Simon; Kilada, Raouf W; Nagelkerken, Ivan; Hansen, Michael M; Page, Timothy J; Riginos, Cynthia; Fry, Brian; Hughes, Jane M

    2015-11-15

    Understanding the drivers and implications of anthropogenic disturbance of ecological connectivity is a key concern for the conservation of biodiversity and ecosystem processes. Here, we review human activities that affect the movements and dispersal of aquatic organisms, including damming of rivers, river regulation, habitat loss and alteration, human-assisted dispersal of organisms and climate change. Using a series of case studies, we show that the insight needed to understand the nature and implications of connectivity, and to underpin conservation and management, is best achieved via data synthesis from multiple analytical approaches. We identify four key knowledge requirements for progressing our understanding of the effects of anthropogenic impacts on ecological connectivity: autecology; population structure; movement characteristics; and environmental tolerance/phenotypic plasticity. Structuring empirical research around these four broad data requirements, and using this information to parameterise appropriate models and develop management approaches, will allow for mitigation of the effects of anthropogenic disturbance on ecological connectivity in aquatic ecosystems. PMID:25917446

  10. Human effects on ecological connectivity in aquatic ecosystems: Integrating scientific approaches to support management and mitigation.

    PubMed

    Crook, David A; Lowe, Winsor H; Allendorf, Frederick W; Erős, Tibor; Finn, Debra S; Gillanders, Bronwyn M; Hadwen, Wade L; Harrod, Chris; Hermoso, Virgilio; Jennings, Simon; Kilada, Raouf W; Nagelkerken, Ivan; Hansen, Michael M; Page, Timothy J; Riginos, Cynthia; Fry, Brian; Hughes, Jane M

    2015-11-15

    Understanding the drivers and implications of anthropogenic disturbance of ecological connectivity is a key concern for the conservation of biodiversity and ecosystem processes. Here, we review human activities that affect the movements and dispersal of aquatic organisms, including damming of rivers, river regulation, habitat loss and alteration, human-assisted dispersal of organisms and climate change. Using a series of case studies, we show that the insight needed to understand the nature and implications of connectivity, and to underpin conservation and management, is best achieved via data synthesis from multiple analytical approaches. We identify four key knowledge requirements for progressing our understanding of the effects of anthropogenic impacts on ecological connectivity: autecology; population structure; movement characteristics; and environmental tolerance/phenotypic plasticity. Structuring empirical research around these four broad data requirements, and using this information to parameterise appropriate models and develop management approaches, will allow for mitigation of the effects of anthropogenic disturbance on ecological connectivity in aquatic ecosystems.

  11. Solar Energy Grid Integration Systems. Final Report of the Princeton Power Systems Development of the 100kW Demand Response Inverter.

    SciTech Connect

    Bower, Ward Isaac; Heavener, Paul; Sena-Henderson, Lisa; Hammell, Darren; Holveck, Mark; David, Carolyn; Akhil, Abbas Ali; Gonzalez, Sigifredo

    2012-01-01

    Initiated in 2008, the Solar Energy Grid Integration (SEGIS) program is a partnership involving the U.S. Department of Energy, Sandia National Laboratories, electric utilities, academic institutions and the private sector. Recognizing the need to diversify the nation's energy portfolio, the SEGIS effort focuses on specific technologies needed to facilitate the integration of large-scale solar power generation into the nation's power grid Sandia National Laboratories (SNL) awarded a contract to Princeton Power Systems, Inc., (PPS) to develop a 100kW Advanced AC-link SEGIS inverter prototype under the Department of Energy Solar Energy Technologies Program for near-term commercial applications. This SEGIS initiative emphasizes the development of advanced inverters, controllers, communications and other balance-of-system components for photovoltaic (PV) distributed power applications. The SEGIS Stage 3 Contract was awarded to PPS on July 28, 2010. PPS developed and implemented a Demand Response Inverter (DRI) during this three-stage program. PPS prepared a 'Site Demonstration Conference' that was held on September 28, 2011, to showcase the cumulative advancements. This demo of the commercial product will be followed by Underwriters Laboratories, Inc., certification by the fourth quarter of 2011, and simultaneously the customer launch and commercial production sometime in late 2011 or early 2012. This final report provides an overview of all three stages and a full-length reporting of activities and accomplishments in Stage 3.

  12. Java Parallel Secure Stream for Grid Computing

    SciTech Connect

    Chen, Jie; Akers, Walter; Chen, Ying; Watson, William

    2001-09-01

    The emergence of high speed wide area networks makes grid computing a reality. However grid applications that need reliable data transfer still have difficulties to achieve optimal TCP performance due to network tuning of TCP window size to improve the bandwidth and to reduce latency on a high speed wide area network. This paper presents a pure Java package called JPARSS (Java Par-allel Secure Stream) that divides data into partitions that are sent over several parallel Java streams simultaneously and allows Java or Web applications to achieve optimal TCP performance in a gird environment without the necessity of tuning the TCP window size. Several experimental results are provided to show that using parallel stream is more effective than tuning TCP window size. In addi-tion X.509 certificate based single sign-on mechanism and SSL based connection establishment are integrated into this package. Finally a few applications using this package will be discussed.

  13. Curriculum Integration in Arts Education: Connecting Multiple Art Forms through the Idea of "Space"

    ERIC Educational Resources Information Center

    Bautista, Alfredo; Tan, Liang See; Ponnusamy, Letchmi Devi; Yau, Xenia

    2016-01-01

    Arts integration research has focused on documenting how the teaching of specific art forms can be integrated with "core" academic subject matters (e.g. science, mathematics and literacy). However, the question of how the teaching of multiple art forms themselves can be integrated in schools remains to be explored by educational…

  14. A PLL Scheme for Synchronization with Grid Voltage Phasor in Active Power Filter Systems

    NASA Astrophysics Data System (ADS)

    Krievs, Oskars; Steiks, Ingars; Ribickis, Leonids

    2010-01-01

    Voltage source inverters connected to the grid in applications such as active power filters require synchronization with the grid voltage. Since in practice the grid voltage can be unbalanced and distorted, but the operation of the whole active filter control system is strongly dependant on precise estimation of grid voltage phase, the fundamental positive sequence phasor of the grid voltage has to be extracted. In this paper a system for smooth estimation of the position of the voltage phasor at the point of common coupling of a parallel active filter system is presented using a sinusoidal signal integrator and a simple software PLL. The performance of the proposed system is verified by simulation and experimental results. The proposed PLL scheme can also be used in other vector oriented control systems.

  15. Grid integrated distributed PV (GridPV).

    SciTech Connect

    Reno, Matthew J.; Coogan, Kyle

    2013-08-01

    This manual provides the documentation of the MATLAB toolbox of functions for using OpenDSS to simulate the impact of solar energy on the distribution system. The majority of the functions are useful for interfacing OpenDSS and MATLAB, and they are of generic use for commanding OpenDSS from MATLAB and retrieving information from simulations. A set of functions is also included for modeling PV plant output and setting up the PV plant in the OpenDSS simulation. The toolbox contains functions for modeling the OpenDSS distribution feeder on satellite images with GPS coordinates. Finally, example simulations functions are included to show potential uses of the toolbox functions. Each function in the toolbox is documented with the function use syntax, full description, function input list, function output list, example use, and example output.

  16. Beyond grid security

    NASA Astrophysics Data System (ADS)

    Hoeft, B.; Epting, U.; Koenig, T.

    2008-07-01

    While many fields relevant to Grid security are already covered by existing working groups, their remit rarely goes beyond the scope of the Grid infrastructure itself. However, security issues pertaining to the internal set-up of compute centres have at least as much impact on Grid security. Thus, this talk will present briefly the EU ISSeG project (Integrated Site Security for Grids). In contrast to groups such as OSCT (Operational Security Coordination Team) and JSPG (Joint Security Policy Group), the purpose of ISSeG is to provide a holistic approach to security for Grid computer centres, from strategic considerations to an implementation plan and its deployment. The generalised methodology of Integrated Site Security (ISS) is based on the knowledge gained during its implementation at several sites as well as through security audits, and this will be briefly discussed. Several examples of ISS implementation tasks at the Forschungszentrum Karlsruhe will be presented, including segregation of the network for administration and maintenance and the implementation of Application Gateways. Furthermore, the web-based ISSeG training material will be introduced. This aims to offer ISS implementation guidance to other Grid installations in order to help avoid common pitfalls.

  17. Prepares Overset Grids for Processing

    1998-04-22

    Many large and complex computational problems require multiple, structured, generically overlapped (overset) grids to obtain numerical solutions in a timely manner. BREAKUP significantly reduces required compute times by preparing overset grids for processing on massively parallel computers. BREAKUP subdivides the original grids for use on a user-specified number of parallel processors. Grid-to-grid and intragrid communications are maintained in the parallel environment via connectivity tables generated by BREAKUP. The subgrids are formed to be statically loadmore » balanced and to incur a minimum of communication between the subgrids. When the output of BREAKUP is submitted to an appropriately modified flow solver, subgrid solutions will be updated simultaneously. This contrasts to the much less efficient solution method of updating each original grid sequentially as done in the past.« less

  18. Prepares Overset Grids for Processing

    SciTech Connect

    Barnette, Daniel W.

    1998-04-22

    Many large and complex computational problems require multiple, structured, generically overlapped (overset) grids to obtain numerical solutions in a timely manner. BREAKUP significantly reduces required compute times by preparing overset grids for processing on massively parallel computers. BREAKUP subdivides the original grids for use on a user-specified number of parallel processors. Grid-to-grid and intragrid communications are maintained in the parallel environment via connectivity tables generated by BREAKUP. The subgrids are formed to be statically load balanced and to incur a minimum of communication between the subgrids. When the output of BREAKUP is submitted to an appropriately modified flow solver, subgrid solutions will be updated simultaneously. This contrasts to the much less efficient solution method of updating each original grid sequentially as done in the past.

  19. Grid enabled Service Support Environment - SSE Grid

    NASA Astrophysics Data System (ADS)

    Goor, Erwin; Paepen, Martine

    2010-05-01

    efficiently. A workflow can be built and submitted for execution on multiple loosely coupled Grids (e.g. at VITO and at ESRIN). It is ensured that the data are processed where they are located. For this purpose the project aims to upgrade the Service Support Environment (SSE) to integrate multi-Grid processing services to be used by the PI for the systematic processing or reprocessing of EO data. For both scenarios described above, two processing modes will be available. In near real-time (NRT), or 'subscription mode', processing, the execution of a workflow is started but suspended a certain step where the workflow waits until certain data are present on the Grid. As soon as the data become available from the sensors, the execution is resumed automatically. In 'historical mode' it is assumed that the data are already present. An other main objective of the SSEGrid project is to propose new or amended versions of 'Web Processing Service' protocols that may be able to bridge geo-spatial Service Oriented Architectures and Open Grid Services Architectures. In this context we will propose the Grid Web Processing Service as an extension of the OGC WPS service to allow for the dynamic deployment of user processes (workflows or Grid processes) and auxiliary data, for the discovery of user auxiliary data, for the query of process status and process audit (execution trace, log file) and for the notification of process completion or failure.

  20. Implementing Production Grids

    NASA Technical Reports Server (NTRS)

    Johnston, William E.; Ziobarth, John (Technical Monitor)

    2002-01-01

    We have presented the essence of experience gained in building two production Grids, and provided some of the global context for this work. As the reader might imagine, there were a lot of false starts, refinements to the approaches and to the software, and several substantial integration projects (SRB and Condor integrated with Globus) to get where we are today. However, the point of this paper is to try and make it substantially easier for others to get to the point where Information Power Grids (IPG) and the DOE Science Grids are today. This is what is needed in order to move us toward the vision of a common cyber infrastructure for science. The author would also like to remind the readers that this paper primarily represents the actual experiences that resulted from specific architectural and software choices during the design and implementation of these two Grids. The choices made were dictated by the criteria laid out in section 1. There is a lot more Grid software available today that there was four years ago, and various of these packages are being integrated into IPG and the DOE Grids. However, the foundation choices of Globus, SRB, and Condor would not be significantly different today than they were four years ago. Nonetheless, if the GGF is successful in its work - and we have every reason to believe that it will be - then in a few years we will see that the 28 functions provided by these packages will be defined in terms of protocols and MIS, and there will be several robust implementations available for each of the basic components, especially the Grid Common Services. The impact of the emerging Web Grid Services work is not yet clear. It will likely have a substantial impact on building higher level services, however it is the opinion of the author that this will in no way obviate the need for the Grid Common Services. These are the foundation of Grids, and the focus of almost all of the operational and persistent infrastructure aspects of Grids.

  1. A free tool integrating GIS features and workflows to evaluate sediment connectivity in alpine catchments

    NASA Astrophysics Data System (ADS)

    Crema, Stefano; Schenato, Luca; Goldin, Beatrice; Marchi, Lorenzo; Cavalli, Marco

    2014-05-01

    The increased interest in sediment connectivity has brought the geomorphologists' community to focus on sediment fluxes as a key process (Cavalli et al., 2013; Heckmann and Schwanghart, 2013). The challenge of dealing with erosion-related processes in alpine catchments is of primary relevance for different fields of investigations and applications, including, but not limited to natural hazards, hydraulic structures design, ecology and stream restoration. The present work focuses on the development of a free tool for sediment connectivity assessment as described in Cavalli et al. (2013), introducing some novel improvements. The choice of going for a free software is motivated by the need of widening the access and improving participation beyond the restrictions on algorithms customization, typical of commercial software. A couple of features further enhance the tool: being completely free and adopting a user-friendly interface, its target audience includes researchers and stakeholders (e.g., local managers and civil protection authorities in charge of planning the priorities of intervention in the territory), being written in Python programming language, it can benefit from optimized algorithms for high-resolution DEMs (Digital Elevation Models) handling and for propagation workflows implementation; these two factors make the tool computationally competitive with the most recent commercial GIS products. The overall goal of this tool is supporting the analysis of sediment connectivity, facing the challenge of widening, as much as possible, the users' community among scientists and stakeholders. This aspect is crucial, as future improvement of this tool will benefit of feedbacks from users in order to improve the quantitative assessment of sediment connectivity as a major input information for the optimal management of mountain areas. References: Cavalli, M., Trevisani, S., Comiti, F., Marchi, L., 2013. Geomorphometric assessment of spatial sediment connectivity in

  2. Strategies and Decision Support Systems for Integrating Variable Energy Resources in Control Centers for Reliable Grid Operations

    SciTech Connect

    Jones, Lawrence E.

    2012-01-05

    A variety of studies have recently evaluated the opportunities for the large-scale integration of wind energy into the US power system. These studies have included, but are not limited to, "20 Percent Wind Energy by 2030: Increasing Wind Energy's Contribution to US Electricity Supply", the "Western Wind and Solar Integration Study", and the "Eastern Wind Integration and Transmission Study." Each of these US based studies have evaluated a variety of activities that can be undertaken by utilities to help integrate wind energy.

  3. Practica continua: Connecting and combining simulation modalities for integrated teaching, learning and assessment.

    PubMed

    Ellaway, Rachel H; Kneebone, Roger; Lachapelle, Kevin; Topps, David

    2009-08-01

    Simulation modalities are generally used independently of one another, largely due to physical and operational limitations to integration. Recent developments are enabling simulators and simulation environments to progress beyond single intervention models towards integrated continua of simulation. Moving to greater integration can improve contextualisation, better management of the transition from individual simulation to clinical practice, and provide wider opportunities to synthesise skills and approaches to practice. Simulation integration may involve experiential, modelling, technical, narrative, and evaluation dimensions; it includes both direct actions and activities, and technical and systems designs. The work in developing these integration continua is ongoing and takes many forms in many places. The framework of 'practica continua' proposed in this article links theoretical approaches and practical examples of integrated uses of simulation in education.

  4. Best Practices In Overset Grid Generation

    NASA Technical Reports Server (NTRS)

    Chan, William M.; Gomez, Reynaldo J., III; Rogers, Stuart E.; Buning, Pieter G.; Kwak, Dochan (Technical Monitor)

    2002-01-01

    Grid generation for overset grids on complex geometry can be divided into four main steps: geometry processing, surface grid generation, volume grid generation and domain connectivity. For each of these steps, the procedures currently practiced by experienced users are described. Typical problems encountered are also highlighted and discussed. Most of the guidelines are derived from experience on a variety of problems including space launch and return vehicles, subsonic transports with propulsion and high lift devices, supersonic vehicles, rotorcraft vehicles, and turbomachinery.

  5. Connections: A Compendium of Integration Ideas. Illinois Tech Prep Innovators. 1992 Compendium. Integrative Teaching Ideas from Illinois Teachers.

    ERIC Educational Resources Information Center

    Illinois State Board of Education, Springfield. Dept. of Adult, Vocational and Technical Education.

    This report contains 51 one-page abstracts of innovative Illinois tech prep programs that integrate academic and vocational education. Each abstract includes the following: curriculum areas, grade level, types of students for whom the program is appropriate, materials needed, suggested resources, a contact person with address and telephone number,…

  6. Current Grid operation and future role of the Grid

    NASA Astrophysics Data System (ADS)

    Smirnova, O.

    2012-12-01

    Grid-like technologies and approaches became an integral part of HEP experiments. Some other scientific communities also use similar technologies for data-intensive computations. The distinct feature of Grid computing is the ability to federate heterogeneous resources of different ownership into a seamless infrastructure, accessible via a single log-on. Like other infrastructures of similar nature, Grid functioning requires not only technologically sound basis, but also reliable operation procedures, monitoring and accounting. The two aspects, technological and operational, are closely related: weaker is the technology, more burden is on operations, and other way around. As of today, Grid technologies are still evolving: at CERN alone, every LHC experiment uses an own Grid-like system. This inevitably creates a heavy load on operations. Infrastructure maintenance, monitoring and incident response are done on several levels, from local system administrators to large international organisations, involving massive human effort worldwide. The necessity to commit substantial resources is one of the obstacles faced by smaller research communities when moving computing to the Grid. Moreover, most current Grid solutions were developed under significant influence of HEP use cases, and thus need additional effort to adapt them to other applications. Reluctance of many non-HEP researchers to use Grid negatively affects the outlook for national Grid organisations, which strive to provide multi-science services. We started from the situation where Grid organisations were fused with HEP laboratories and national HEP research programmes; we hope to move towards the world where Grid will ultimately reach the status of generic public computing and storage service provider and permanent national and international Grid infrastructures will be established. How far will we be able to advance along this path, depends on us. If no standardisation and convergence efforts will take place

  7. Fibonacci Grids

    NASA Technical Reports Server (NTRS)

    Swinbank, Richard; Purser, James

    2006-01-01

    Recent years have seen a resurgence of interest in a variety of non-standard computational grids for global numerical prediction. The motivation has been to reduce problems associated with the converging meridians and the polar singularities of conventional regular latitude-longitude grids. A further impetus has come from the adoption of massively parallel computers, for which it is necessary to distribute work equitably across the processors; this is more practicable for some non-standard grids. Desirable attributes of a grid for high-order spatial finite differencing are: (i) geometrical regularity; (ii) a homogeneous and approximately isotropic spatial resolution; (iii) a low proportion of the grid points where the numerical procedures require special customization (such as near coordinate singularities or grid edges). One family of grid arrangements which, to our knowledge, has never before been applied to numerical weather prediction, but which appears to offer several technical advantages, are what we shall refer to as "Fibonacci grids". They can be thought of as mathematically ideal generalizations of the patterns occurring naturally in the spiral arrangements of seeds and fruit found in sunflower heads and pineapples (to give two of the many botanical examples). These grids possess virtually uniform and highly isotropic resolution, with an equal area for each grid point. There are only two compact singular regions on a sphere that require customized numerics. We demonstrate the practicality of these grids in shallow water simulations, and discuss the prospects for efficiently using these frameworks in three-dimensional semi-implicit and semi-Lagrangian weather prediction or climate models.

  8. On unstructured grids and solvers

    NASA Technical Reports Server (NTRS)

    Barth, T. J.

    1990-01-01

    The fundamentals and the state-of-the-art technology for unstructured grids and solvers are highlighted. Algorithms and techniques pertinent to mesh generation are discussed. It is shown that grid generation and grid manipulation schemes rely on fast multidimensional searching. Flow solution techniques for the Euler equations, which can be derived from the integral form of the equations are discussed. Sample calculations are also provided.

  9. Connecting with Place: Implications of Integrating Cultural Values into the School Curriculum in Alaska

    ERIC Educational Resources Information Center

    Takano, Takako; Higgins, Peter; McLaughlin, Pat

    2009-01-01

    Many authors primarily from industrialised nations discuss human relationships with the natural environment in the context of global environmental issues, and highlight the close relationships that "traditional" societies have with nature. There is a growing trend among indigenous people in North America to restore such a connection with the land…

  10. Mitigation of Power Quality Problems in Grid-Interactive Distributed Generation System

    NASA Astrophysics Data System (ADS)

    Bhende, C. N.; Kalam, A.; Malla, S. G.

    2016-04-01

    Having an inter-tie between low/medium voltage grid and distributed generation (DG), both exposes to power quality (PQ) problems created by each other. This paper addresses various PQ problems arise due to integration of DG with grid. The major PQ problems are due to unbalanced and non-linear load connected at DG, unbalanced voltage variations on transmission line and unbalanced grid voltages which severely affect the performance of the system. To mitigate the above mentioned PQ problems, a novel integrated control of distribution static shunt compensator (DSTATCOM) is presented in this paper. DSTATCOM control helps in reducing the unbalance factor of PCC voltage. It also eliminates harmonics from line currents and makes them balanced. Moreover, DSTATCOM supplies the reactive power required by the load locally and hence, grid need not to supply the reactive power. To show the efficacy of the proposed controller, several operating conditions are considered and verified through simulation using MATLAB/SIMULINK.

  11. A semantic grid infrastructure enabling integrated access and analysis of multilevel biomedical data in support of postgenomic clinical trials on cancer.

    PubMed

    Tsiknakis, Manolis; Brochhausen, Mathias; Nabrzyski, Jarek; Pucacki, Juliusz; Sfakianakis, Stelios G; Potamias, George; Desmedt, Cristine; Kafetzopoulos, Dimitris

    2008-03-01

    This paper reports on original results of the Advancing Clinico-Genomic Trials on Cancer integrated project focusing on the design and development of a European biomedical grid infrastructure in support of multicentric, postgenomic clinical trials (CTs) on cancer. Postgenomic CTs use multilevel clinical and genomic data and advanced computational analysis and visualization tools to test hypothesis in trying to identify the molecular reasons for a disease and the stratification of patients in terms of treatment. This paper provides a presentation of the needs of users involved in postgenomic CTs, and presents such needs in the form of scenarios, which drive the requirements engineering phase of the project. Subsequently, the initial architecture specified by the project is presented, and its services are classified and discussed. A key set of such services are those used for wrapping heterogeneous clinical trial management systems and other public biological databases. Also, the main technological challenge, i.e. the design and development of semantically rich grid services is discussed. In achieving such an objective, extensive use of ontologies and metadata are required. The Master Ontology on Cancer, developed by the project, is presented, and our approach to develop the required metadata registries, which provide semantically rich information about available data and computational services, is provided. Finally, a short discussion of the work lying ahead is included.

  12. Fault ride-through enhancement using an enhanced field oriented control technique for converters of grid connected DFIG and STATCOM for different types of faults.

    PubMed

    Ananth, D V N; Nagesh Kumar, G V

    2016-05-01

    With increase in electric power demand, transmission lines were forced to operate close to its full load and due to the drastic change in weather conditions, thermal limit is increasing and the system is operating with less security margin. To meet the increased power demand, a doubly fed induction generator (DFIG) based wind generation system is a better alternative. For improving power flow capability and increasing security STATCOM can be adopted. As per modern grid rules, DFIG needs to operate without losing synchronism called low voltage ride through (LVRT) during severe grid faults. Hence, an enhanced field oriented control technique (EFOC) was adopted in Rotor Side Converter of DFIG converter to improve power flow transfer and to improve dynamic and transient stability. A STATCOM is coordinated to the system for obtaining much better stability and enhanced operation during grid fault. For the EFOC technique, rotor flux reference changes its value from synchronous speed to zero during fault for injecting current at the rotor slip frequency. In this process DC-Offset component of flux is controlled, decomposition during symmetric and asymmetric faults. The offset decomposition of flux will be oscillatory in a conventional field oriented control, whereas in EFOC it was aimed to damp quickly. This paper mitigates voltage and limits surge currents to enhance the operation of DFIG during symmetrical and asymmetrical faults. The system performance with different types of faults like single line to ground, double line to ground and triple line to ground was applied and compared without and with a STATCOM occurring at the point of common coupling with fault resistance of a very small value at 0.001Ω.

  13. VisIVO: a Visualization Toolkit towards Grid Environment

    NASA Astrophysics Data System (ADS)

    Costa, A.; Becciani, U.; Comparato, M.; Gheller, C.

    2006-07-01

    VisIVO is a package for supporting the visualization and analysis of astrophysical three-dimensional data. This tool gives a 3D graphic representation of data exploiting VTK technologies. We have integrated the VisIVO tool with VO services: connection to a VO web service, retrieval and dealing with data in the VOTable, FITS or ASCII formats. We are developing new plugins for the data analysis as VWS (VisIVO Web Services) giving to our project more interoperability with widely used analysis tools like group finders (i.e. HOP). We introduce some enhancements of the VisIVO framework allowing a user to use grid technologies in the TriGrid VL (Trinacria Grid Virtual Laboratory) environment.

  14. Accessing Wind Tunnels From NASA's Information Power Grid

    NASA Technical Reports Server (NTRS)

    Becker, Jeff; Biegel, Bryan (Technical Monitor)

    2002-01-01

    The NASA Ames wind tunnel customers are one of the first users of the Information Power Grid (IPG) storage system at the NASA Advanced Supercomputing Division. We wanted to be able to store their data on the IPG so that it could be accessed remotely in a secure but timely fashion. In addition, incorporation into the IPG allows future use of grid computational resources, e.g., for post-processing of data, or to do side-by-side CFD validation. In this paper, we describe the integration of grid data access mechanisms with the existing DARWIN web-based system that is used to access wind tunnel test data. We also show that the combined system has reasonable performance: wind tunnel data may be retrieved at 50Mbits/s over a 100 base T network connected to the IPG storage server.

  15. Best Practices in Grid Integration of Variable Wind Power: Summary of Recent US Case Study Results and Mitigation Measures

    SciTech Connect

    Smith, J. Charles; Parsons, Brian; Acker, Thomas; Milligan, Michael; Zavidil, Robert; Schuerger, Matthew; DeMeo, Edgar

    2010-01-22

    This paper will summarize results from a number of utility wind integration case studies conducted recently in the US, and outline a number of mitigation measures based on insights from those studies.

  16. SchizConnect: Mediating neuroimaging databases on schizophrenia and related disorders for large-scale integration.

    PubMed

    Wang, Lei; Alpert, Kathryn I; Calhoun, Vince D; Cobia, Derin J; Keator, David B; King, Margaret D; Kogan, Alexandr; Landis, Drew; Tallis, Marcelo; Turner, Matthew D; Potkin, Steven G; Turner, Jessica A; Ambite, Jose Luis

    2016-01-01

    SchizConnect (www.schizconnect.org) is built to address the issues of multiple data repositories in schizophrenia neuroimaging studies. It includes a level of mediation--translating across data sources--so that the user can place one query, e.g. for diffusion images from male individuals with schizophrenia, and find out from across participating data sources how many datasets there are, as well as downloading the imaging and related data. The current version handles the Data Usage Agreements across different studies, as well as interpreting database-specific terminologies into a common framework. New data repositories can also be mediated to bring immediate access to existing datasets. Compared with centralized, upload data sharing models, SchizConnect is a unique, virtual database with a focus on schizophrenia and related disorders that can mediate live data as information is being updated at each data source. It is our hope that SchizConnect can facilitate testing new hypotheses through aggregated datasets, promoting discovery related to the mechanisms underlying schizophrenic dysfunction. PMID:26142271

  17. Analysis and design of a 10 to 30 kW grid-connected solar power system for the JPL fire station and first aid station

    NASA Technical Reports Server (NTRS)

    Josephs, R. H.

    1982-01-01

    The design and performance of a modestly sized utility-connected power conditioning system and its supporting photovoltaic collector are described and estimated. Utility preparations and guidelines to conform with the output of a small generating station with that of a large power network are examined.

  18. MOLGENIS/connect: a system for semi-automatic integration of heterogeneous phenotype data with applications in biobanks

    PubMed Central

    Pang, Chao; van Enckevort, David; de Haan, Mark; Kelpin, Fleur; Jetten, Jonathan; Hendriksen, Dennis; de Boer, Tommy; Charbon, Bart; Winder, Erwin; van der Velde, K. Joeri; Doiron, Dany; Fortier, Isabel; Hillege, Hans

    2016-01-01

    Motivation: While the size and number of biobanks, patient registries and other data collections are increasing, biomedical researchers still often need to pool data for statistical power, a task that requires time-intensive retrospective integration. Results: To address this challenge, we developed MOLGENIS/connect, a semi-automatic system to find, match and pool data from different sources. The system shortlists relevant source attributes from thousands of candidates using ontology-based query expansion to overcome variations in terminology. Then it generates algorithms that transform source attributes to a common target DataSchema. These include unit conversion, categorical value matching and complex conversion patterns (e.g. calculation of BMI). In comparison to human-experts, MOLGENIS/connect was able to auto-generate 27% of the algorithms perfectly, with an additional 46% needing only minor editing, representing a reduction in the human effort and expertise needed to pool data. Availability and Implementation: Source code, binaries and documentation are available as open-source under LGPLv3 from http://github.com/molgenis/molgenis and www.molgenis.org/connect. Contact: m.a.swertz@rug.nl Supplementary information: Supplementary data are available at Bioinformatics online. PMID:27153686

  19. Assessing Impact of Large-Scale Distributed Residential HVAC Control Optimization on Electricity Grid Operation and Renewable Energy Integration

    NASA Astrophysics Data System (ADS)

    Corbin, Charles D.

    Demand management is an important component of the emerging Smart Grid, and a potential solution to the supply-demand imbalance occurring increasingly as intermittent renewable electricity is added to the generation mix. Model predictive control (MPC) has shown great promise for controlling HVAC demand in commercial buildings, making it an ideal solution to this problem. MPC is believed to hold similar promise for residential applications, yet very few examples exist in the literature despite a growing interest in residential demand management. This work explores the potential for residential buildings to shape electric demand at the distribution feeder level in order to reduce peak demand, reduce system ramping, and increase load factor using detailed sub-hourly simulations of thousands of buildings coupled to distribution power flow software. More generally, this work develops a methodology for the directed optimization of residential HVAC operation using a distributed but directed MPC scheme that can be applied to today's programmable thermostat technologies to address the increasing variability in electric supply and demand. Case studies incorporating varying levels of renewable energy generation demonstrate the approach and highlight important considerations for large-scale residential model predictive control.

  20. Modelling the potential for wind energy integration on China’s coal-heavy electricity grid

    NASA Astrophysics Data System (ADS)

    Davidson, Michael R.; Zhang, Da; Xiong, Weiming; Zhang, Xiliang; Karplus, Valerie J.

    2016-07-01

    Expanding the use of wind energy for electricity generation forms an integral part of China’s efforts to address degraded air quality and climate change. However, the integration of wind energy into China’s coal-heavy electricity system presents significant challenges owing to wind’s variability and the grid’s system-wide inflexibilities. Here we develop a model to predict how much wind energy can be generated and integrated into China’s electricity mix, and estimate a potential production of 2.6 petawatt-hours (PWh) per year in 2030. Although this represents 26% of total projected electricity demand, it is only 10% of the total estimated physical potential of wind resources in the country. Increasing the operational flexibility of China’s coal fleet would allow wind to deliver nearly three-quarters of China’s target of producing 20% of primary energy from non-fossil sources by 2030.

  1. Formulation of an explicit-multiple-time-step time integration method for use in a global primitive equation grid model

    NASA Technical Reports Server (NTRS)

    Chao, W. C.

    1982-01-01

    With appropriate modifications, a recently proposed explicit-multiple-time-step scheme (EMTSS) is incorporated into the UCLA model. In this scheme, the linearized terms in the governing equations that generate the gravity waves are split into different vertical modes. Each mode is integrated with an optimal time step, and at periodic intervals these modes are recombined. The other terms are integrated with a time step dictated by the CFL condition for low-frequency waves. This large time step requires a special modification of the advective terms in the polar region to maintain stability. Test runs for 72 h show that EMTSS is a stable, efficient and accurate scheme.

  2. Brain Structural Integrity and Intrinsic Functional Connectivity Forecast 6 Year Longitudinal Growth in Children's Numerical Abilities

    PubMed Central

    Kochalka, John; Ngoon, Tricia J.; Wu, Sarah S.; Qin, Shaozheng; Battista, Christian

    2015-01-01

    Early numerical proficiency lays the foundation for acquiring quantitative skills essential in today's technological society. Identification of cognitive and brain markers associated with long-term growth of children's basic numerical computation abilities is therefore of utmost importance. Previous attempts to relate brain structure and function to numerical competency have focused on behavioral measures from a single time point. Thus, little is known about the brain predictors of individual differences in growth trajectories of numerical abilities. Using a longitudinal design, with multimodal imaging and machine-learning algorithms, we investigated whether brain structure and intrinsic connectivity in early childhood are predictive of 6 year outcomes in numerical abilities spanning childhood and adolescence. Gray matter volume at age 8 in distributed brain regions, including the ventrotemporal occipital cortex (VTOC), the posterior parietal cortex, and the prefrontal cortex, predicted longitudinal gains in numerical, but not reading, abilities. Remarkably, intrinsic connectivity analysis revealed that the strength of functional coupling among these regions also predicted gains in numerical abilities, providing novel evidence for a network of brain regions that works in concert to promote numerical skill acquisition. VTOC connectivity with posterior parietal, anterior temporal, and dorsolateral prefrontal cortices emerged as the most extensive network predicting individual gains in numerical abilities. Crucially, behavioral measures of mathematics, IQ, working memory, and reading did not predict children's gains in numerical abilities. Our study identifies, for the first time, functional circuits in the human brain that scaffold the development of numerical skills, and highlights potential biomarkers for identifying children at risk for learning difficulties. SIGNIFICANCE STATEMENT Children show substantial individual differences in math abilities and ease of math

  3. Physical Exercise Keeps the Brain Connected: Biking Increases White Matter Integrity in Patients With Schizophrenia and Healthy Controls

    PubMed Central

    Svatkova, Alena; Mandl, René C.W.; Scheewe, Thomas W.; Cahn, Wiepke; Kahn, René S.; Hulshoff Pol, Hilleke E.

    2015-01-01

    It has been shown that learning a new skill leads to structural changes in the brain. However, it is unclear whether it is the acquisition or continuous practicing of the skill that causes this effect and whether brain connectivity of patients with schizophrenia can benefit from such practice. We examined the effect of 6 months exercise on a stationary bicycle on the brain in patients with schizophrenia and healthy controls. Biking is an endemic skill in the Netherlands and thus offers an ideal situation to disentangle the effects of learning vs practice. The 33 participating patients with schizophrenia and 48 healthy individuals were assigned to either one of two conditions, ie, physical exercise or life-as-usual, balanced for diagnosis. Diffusion tensor imaging brain scans were made prior to and after intervention. We demonstrate that irrespective of diagnosis regular physical exercise of an overlearned skill, such as bicycling, significantly increases the integrity, especially of motor functioning related, white matter fiber tracts whereas life-as-usual leads to a decrease in fiber integrity. Our findings imply that exercise of an overlearned physical skill improves brain connectivity in patients and healthy individuals. This has important implications for understanding the effect of fitness programs on the brain in both healthy subjects and patients with schizophrenia. Moreover, the outcome may even apply to the nonphysical realm. PMID:25829377

  4. Physical Exercise Keeps the Brain Connected: Biking Increases White Matter Integrity in Patients With Schizophrenia and Healthy Controls.

    PubMed

    Svatkova, Alena; Mandl, René C W; Scheewe, Thomas W; Cahn, Wiepke; Kahn, René S; Hulshoff Pol, Hilleke E

    2015-07-01

    It has been shown that learning a new skill leads to structural changes in the brain. However, it is unclear whether it is the acquisition or continuous practicing of the skill that causes this effect and whether brain connectivity of patients with schizophrenia can benefit from such practice. We examined the effect of 6 months exercise on a stationary bicycle on the brain in patients with schizophrenia and healthy controls. Biking is an endemic skill in the Netherlands and thus offers an ideal situation to disentangle the effects of learning vs practice. The 33 participating patients with schizophrenia and 48 healthy individuals were assigned to either one of two conditions, ie, physical exercise or life-as-usual, balanced for diagnosis. Diffusion tensor imaging brain scans were made prior to and after intervention. We demonstrate that irrespective of diagnosis regular physical exercise of an overlearned skill, such as bicycling, significantly increases the integrity, especially of motor functioning related, white matter fiber tracts whereas life-as-usual leads to a decrease in fiber integrity. Our findings imply that exercise of an overlearned physical skill improves brain connectivity in patients and healthy individuals. This has important implications for understanding the effect of fitness programs on the brain in both healthy subjects and patients with schizophrenia. Moreover, the outcome may even apply to the nonphysical realm.

  5. A Simple Instant-Estimation Method for Time-Average Quantities of Single-Phase Power and Application to Single-Phase Power Grid Connection by Inverter

    NASA Astrophysics Data System (ADS)

    Shinnaka, Shinji

    This paper presents and analyzes a new simple instant-estimation method for time-average quantities such as rms-values of voltage and current, active and reactive powers, and power factor for single-phase power with the fundamental component of constant or nearly-constant frequency by measuring instantaneous values of voltage and current. According to the analyses, the method can instantly estimate time average values with accuracy of the fundamental frequency, and estimation accuracy of power factor is about two times better than that of voltage, current, and powers. The instant-estimation method is simple and can be easily applied to single-phase power control systems that are expected to control instantly and continuously power factor on a single-phase grid by inverter. Based on the proposed instant-estimation method, two-methods for such power control systems are also proposed and their usefulness is verified through simulations.

  6. Design and implementation of a new modified sliding mode controller for grid-connected inverter to controlling the voltage and frequency.

    PubMed

    Ghanbarian, Mohammad Mehdi; Nayeripour, Majid; Rajaei, Amirhossein; Mansouri, Mohammad Mahdi

    2016-03-01

    As the output power of a microgrid with renewable energy sources should be regulated based on the grid conditions, using robust controllers to share and balance the power in order to regulate the voltage and frequency of microgrid is critical. Therefore a proper control system is necessary for updating the reference signals and determining the proportion of each inverter in the microgrid control. This paper proposes a new adaptive method which is robust while the conditions are changing. This controller is based on a modified sliding mode controller which provides adapting conditions in linear and nonlinear loads. The performance of the proposed method is validated by representing the simulation results and experimental lab results. PMID:26704720

  7. Design and implementation of a new modified sliding mode controller for grid-connected inverter to controlling the voltage and frequency.

    PubMed

    Ghanbarian, Mohammad Mehdi; Nayeripour, Majid; Rajaei, Amirhossein; Mansouri, Mohammad Mahdi

    2016-03-01

    As the output power of a microgrid with renewable energy sources should be regulated based on the grid conditions, using robust controllers to share and balance the power in order to regulate the voltage and frequency of microgrid is critical. Therefore a proper control system is necessary for updating the reference signals and determining the proportion of each inverter in the microgrid control. This paper proposes a new adaptive method which is robust while the conditions are changing. This controller is based on a modified sliding mode controller which provides adapting conditions in linear and nonlinear loads. The performance of the proposed method is validated by representing the simulation results and experimental lab results.

  8. The data storage grid: the next generation of fault-tolerant storage for backup and disaster recovery of clinical images

    NASA Astrophysics Data System (ADS)

    King, Nelson E.; Liu, Brent; Zhou, Zheng; Documet, Jorge; Huang, H. K.

    2005-04-01

    Grid Computing represents the latest and most exciting technology to evolve from the familiar realm of parallel, peer-to-peer and client-server models that can address the problem of fault-tolerant storage for backup and recovery of clinical images. We have researched and developed a novel Data Grid testbed involving several federated PAC systems based on grid architecture. By integrating a grid computing architecture to the DICOM environment, a failed PACS archive can recover its image data from others in the federation in a timely and seamless fashion. The design reflects the five-layer architecture of grid computing: Fabric, Resource, Connectivity, Collective, and Application Layers. The testbed Data Grid architecture representing three federated PAC systems, the Fault-Tolerant PACS archive server at the Image Processing and Informatics Laboratory, Marina del Rey, the clinical PACS at Saint John's Health Center, Santa Monica, and the clinical PACS at the Healthcare Consultation Center II, USC Health Science Campus, will be presented. The successful demonstration of the Data Grid in the testbed will provide an understanding of the Data Grid concept in clinical image data backup as well as establishment of benchmarks for performance from future grid technology improvements and serve as a road map for expanded research into large enterprise and federation level data grids to guarantee 99.999 % up time.

  9. EEG-MEG Integration Enhances the Characterization of Functional and Effective Connectivity in the Resting State Network

    PubMed Central

    Mideksa, Kidist Gebremariam; Anwar, Abdul Rauf; Stephani, Ulrich; Deuschl, Günther; Freitag, Christine M.; Siniatchkin, Michael

    2015-01-01

    At the sensor level many aspects, such as spectral power, functional and effective connectivity as well as relative-power-ratio ratio (RPR) and spatial resolution have been comprehensively investigated through both electroencephalography (EEG) and magnetoencephalography (MEG). Despite this, differences between both modalities have not yet been systematically studied by direct comparison. It remains an open question as to whether the integration of EEG and MEG data would improve the information obtained from the above mentioned parameters. Here, EEG (64-channel system) and MEG (275 sensor system) were recorded simultaneously in conditions with eyes open (EO) and eyes closed (EC) in 29 healthy adults. Spectral power, functional and effective connectivity, RPR, and spatial resolution were analyzed at five different frequency bands (delta, theta, alpha, beta and gamma). Networks of functional and effective connectivity were described using a spatial filter approach called the dynamic imaging of coherent sources (DICS) followed by the renormalized partial directed coherence (RPDC). Absolute mean power at the sensor level was significantly higher in EEG than in MEG data in both EO and EC conditions. At the source level, there was a trend towards a better performance of the combined EEG+MEG analysis compared with separate EEG or MEG analyses for the source mean power, functional correlation, effective connectivity for both EO and EC. The network of coherent sources and the spatial resolution were similar for both the EEG and MEG data if they were analyzed separately. Results indicate that the combined approach has several advantages over the separate analyses of both EEG and MEG. Moreover, by a direct comparison of EEG and MEG, EEG was characterized by significantly higher values in all measured parameters in both sensor and source level. All the above conclusions are specific to the resting state task and the specific analysis used in this study to have general

  10. EEG-MEG Integration Enhances the Characterization of Functional and Effective Connectivity in the Resting State Network.

    PubMed

    Muthuraman, Muthuraman; Moliadze, Vera; Mideksa, Kidist Gebremariam; Anwar, Abdul Rauf; Stephani, Ulrich; Deuschl, Günther; Freitag, Christine M; Siniatchkin, Michael

    2015-01-01

    At the sensor level many aspects, such as spectral power, functional and effective connectivity as well as relative-power-ratio ratio (RPR) and spatial resolution have been comprehensively investigated through both electroencephalography (EEG) and magnetoencephalography (MEG). Despite this, differences between both modalities have not yet been systematically studied by direct comparison. It remains an open question as to whether the integration of EEG and MEG data would improve the information obtained from the above mentioned parameters. Here, EEG (64-channel system) and MEG (275 sensor system) were recorded simultaneously in conditions with eyes open (EO) and eyes closed (EC) in 29 healthy adults. Spectral power, functional and effective connectivity, RPR, and spatial resolution were analyzed at five different frequency bands (delta, theta, alpha, beta and gamma). Networks of functional and effective connectivity were described using a spatial filter approach called the dynamic imaging of coherent sources (DICS) followed by the renormalized partial directed coherence (RPDC). Absolute mean power at the sensor level was significantly higher in EEG than in MEG data in both EO and EC conditions. At the source level, there was a trend towards a better performance of the combined EEG+MEG analysis compared with separate EEG or MEG analyses for the source mean power, functional correlation, effective connectivity for both EO and EC. The network of coherent sources and the spatial resolution were similar for both the EEG and MEG data if they were analyzed separately. Results indicate that the combined approach has several advantages over the separate analyses of both EEG and MEG. Moreover, by a direct comparison of EEG and MEG, EEG was characterized by significantly higher values in all measured parameters in both sensor and source level. All the above conclusions are specific to the resting state task and the specific analysis used in this study to have general

  11. EEG-MEG Integration Enhances the Characterization of Functional and Effective Connectivity in the Resting State Network.

    PubMed

    Muthuraman, Muthuraman; Moliadze, Vera; Mideksa, Kidist Gebremariam; Anwar, Abdul Rauf; Stephani, Ulrich; Deuschl, Günther; Freitag, Christine M; Siniatchkin, Michael

    2015-01-01

    At the sensor level many aspects, such as spectral power, functional and effective connectivity as well as relative-power-ratio ratio (RPR) and spatial resolution have been comprehensively investigated through both electroencephalography (EEG) and magnetoencephalography (MEG). Despite this, differences between both modalities have not yet been systematically studied by direct comparison. It remains an open question as to whether the integration of EEG and MEG data would improve the information obtained from the above mentioned parameters. Here, EEG (64-channel system) and MEG (275 sensor system) were recorded simultaneously in conditions with eyes open (EO) and eyes closed (EC) in 29 healthy adults. Spectral power, functional and effective connectivity, RPR, and spatial resolution were analyzed at five different frequency bands (delta, theta, alpha, beta and gamma). Networks of functional and effective connectivity were described using a spatial filter approach called the dynamic imaging of coherent sources (DICS) followed by the renormalized partial directed coherence (RPDC). Absolute mean power at the sensor level was significantly higher in EEG than in MEG data in both EO and EC conditions. At the source level, there was a trend towards a better performance of the combined EEG+MEG analysis compared with separate EEG or MEG analyses for the source mean power, functional correlation, effective connectivity for both EO and EC. The network of coherent sources and the spatial resolution were similar for both the EEG and MEG data if they were analyzed separately. Results indicate that the combined approach has several advantages over the separate analyses of both EEG and MEG. Moreover, by a direct comparison of EEG and MEG, EEG was characterized by significantly higher values in all measured parameters in both sensor and source level. All the above conclusions are specific to the resting state task and the specific analysis used in this study to have general

  12. T2D@ZJU: a knowledgebase integrating heterogeneous connections associated with type 2 diabetes mellitus.

    PubMed

    Yang, Zhenzhong; Yang, Jihong; Liu, Wei; Wu, Leihong; Xing, Li; Wang, Yi; Fan, Xiaohui; Cheng, Yiyu

    2013-01-01

    Type 2 diabetes mellitus (T2D), affecting >90% of the diabetic patients, is one of the major threats to human health. A comprehensive understanding of the mechanisms of T2D at molecular level is essential to facilitate the related translational research. Here, we introduce a comprehensive and up-to-date knowledgebase for T2D, i.e. T2D@ZJU. T2D@ZJU contains three levels of heterogeneous connections associated with T2D, which is retrieved from pathway databases, protein-protein interaction databases and literature, respectively. In current release, T2D@ZJU contains 1078 T2D related entities such as proteins, protein complexes, drugs and others together with their corresponding relationships, which include 3069 manually curated connections, 14,893 protein-protein interactions and 26,716 relationships identified by text-mining technology. Moreover, T2D@ZJU provides a user-friendly web interface for users to browse and search data. A Cytoscape Web-based interactive network browser is available to visualize the corresponding network relationships between T2D-related entities. The functionality of T2D@ZJU is shown by means of several case studies. Database URL: http://tcm.zju.edu.cn/t2d.

  13. Connecting the STEM Dots: Measuring the Effect of an Integrated Engineering Design Intervention

    ERIC Educational Resources Information Center

    Hernandez, Paul R.; Bodin, Ralph; Elliott, Jonathan W.; Ibrahim, Badaruddin; Rambo-Hernandez, Karen E.; Chen, Thomas W.; de Miranda, Michael A.

    2014-01-01

    Recent publications have elevated the priority of increasing the integration of Science, Technology, Engineering, and Mathematics (STEM) content for K-12 education. The STEM education community must invest in the development of valid and reliable to scales to measure STEM content, knowledge fusion, and perceptions of the nature of STEM. This brief…

  14. Encouraging Connections: Integrating Expressive Art and Drama into Therapeutic Social Skills Training with Adolescents

    ERIC Educational Resources Information Center

    Lenz, A. Stephen; Holman, Rachel L.; Dominguez, Denise L.

    2010-01-01

    The effective use of social skills has been positively associated with career success, romantic involvement, academic achievement, and mood. In response, counselors often integrate social skills training into counseling interventions with adolescents to encourage authentic and effective interactions with others. We illustrate some therapeutic…

  15. Connection + Collaboration = Successful Integration of Technology in a Large High School: Formula for Success

    ERIC Educational Resources Information Center

    Lankau, Louise

    2015-01-01

    In this article, Summer Creek High School (Harris County, Texas) librarian, Louise Lankau shares a formula for successfully integrating technology via the school library and reaching every department and teacher in a school of 2,500 students and 170 teachers. The challenge is that the teaching staff at Summer Creek increases each year to…

  16. Service Integration in Colorado: Connecting Programs To Provide Better Services in Mesa and El Paso Counties.

    ERIC Educational Resources Information Center

    Ragan, Mark

    Efforts to integrate the delivery of human service programs (HSP) in Colorado's El Paso County and Mesa County were examined through site visits and meetings with 34 members of HSP staff in both counties. The site visits confirmed that staff and management of HSP in both counties have implemented a series of client-centered processes to provide…

  17. Inquiry and Connections in Integrated Science Content Courses for Elementary Education Majors

    ERIC Educational Resources Information Center

    Varelas, Maria; Plotnick, Roy; Wink, Donald; Fan, Qian; Harris, Yvonne

    2008-01-01

    An interdisciplinary team of science and education faculty at the University of Illinois at Chicago and several Chicago-area community colleges developed and implemented a series of four integrated, inquiry-based science courses for preservice elementary school teachers. All four courses are based on guiding principles taken from the rich…

  18. University Students' Perceptions of Integrated Performance Assessment and the Connection between Classroom Learning and Assessment

    ERIC Educational Resources Information Center

    Zapata, Gabriela C.

    2016-01-01

    In 2013, Integrated Performance Assessment (IPA) was adopted at all levels of instruction at a private university in southern California. The study reports the opinions of 1,236 Novice, Intermediate Low, and Intermediate Mid Spanish students concerning IPA and their perceptions of the way in which classroom instruction was reflected in the content…

  19. Inter-connections between human health and ecological integrity: An organizational framework for research and development

    EPA Science Inventory

    A Pellston workshop entitled, Interconnections between Human Health and Ecological Integrity, was held in 2000. Jointly sponsored by the Society of Environmental Toxicology and Chemistry (SETAC) and the Society of Toxicology (SOT), the workshop was motivated by the concern of hum...

  20. Connecting the dots: using 'big data' to build an efficient, integrated service line.

    PubMed

    Golberg, Dana; Leonard, Robert; McEnroe, Sean; McDonald, Jeff

    2015-08-01

    As seen in the case of musculoskeletal care, the broad steps hospitals and health systems should take to optimize service lines include: Understanding their market's demand for services. Guiding patients through integrated, patient-centric care. Taking patient engagement to the next level.

  1. Wind Energy Management System EMS Integration Project: Incorporating Wind Generation and Load Forecast Uncertainties into Power Grid Operations

    SciTech Connect

    Makarov, Yuri V.; Huang, Zhenyu; Etingov, Pavel V.; Ma, Jian; Guttromson, Ross T.; Subbarao, Krishnappa; Chakrabarti, Bhujanga B.

    2010-01-01

    unique features make this work a significant step forward toward the objective of incorporating of wind, solar, load, and other uncertainties into power system operations. Currently, uncertainties associated with wind and load forecasts, as well as uncertainties associated with random generator outages and unexpected disconnection of supply lines, are not taken into account in power grid operation. Thus, operators have little means to weigh the likelihood and magnitude of upcoming events of power imbalance. In this project, funded by the U.S. Department of Energy (DOE), a framework has been developed for incorporating uncertainties associated with wind and load forecast errors, unpredicted ramps, and forced generation disconnections into the energy management system (EMS) as well as generation dispatch and commitment applications. A new approach to evaluate the uncertainty ranges for the required generation performance envelope including balancing capacity, ramping capability, and ramp duration has been proposed. The approach includes three stages: forecast and actual data acquisition, statistical analysis of retrospective information, and prediction of future grid balancing requirements for specified time horizons and confidence levels. Assessment of the capacity and ramping requirements is performed using a specially developed probabilistic algorithm based on a histogram analysis, incorporating all sources of uncertainties of both continuous (wind and load forecast errors) and discrete (forced generator outages and start-up failures) nature. A new method called the “flying brick” technique has been developed to evaluate the look-ahead required generation performance envelope for the worst case scenario within a user-specified confidence level. A self-validation algorithm has been developed to validate the accuracy of the confidence intervals.

  2. Grid Computing

    NASA Astrophysics Data System (ADS)

    Foster, Ian

    2001-08-01

    The term "Grid Computing" refers to the use, for computational purposes, of emerging distributed Grid infrastructures: that is, network and middleware services designed to provide on-demand and high-performance access to all important computational resources within an organization or community. Grid computing promises to enable both evolutionary and revolutionary changes in the practice of computational science and engineering based on new application modalities such as high-speed distributed analysis of large datasets, collaborative engineering and visualization, desktop access to computation via "science portals," rapid parameter studies and Monte Carlo simulations that use all available resources within an organization, and online analysis of data from scientific instruments. In this article, I examine the status of Grid computing circa 2000, briefly reviewing some relevant history, outlining major current Grid research and development activities, and pointing out likely directions for future work. I also present a number of case studies, selected to illustrate the potential of Grid computing in various areas of science.

  3. Neutron Science TeraGrid Gateway

    NASA Astrophysics Data System (ADS)

    Lynch, Vickie; Chen, Meili; Cobb, John; Kohl, Jim; Miller, Steve; Speirs, David; Vazhkudai, Sudharshan

    2010-11-01

    The unique contributions of the Neutron Science TeraGrid Gateway (NSTG) are the connection of national user facility instrument data sources to the integrated cyberinfrastructure of the National Science FoundationTeraGrid and the development of a neutron science gateway that allows neutron scientists to use TeraGrid resources to analyze their data, including comparison of experiment with simulation. The NSTG is working in close collaboration with the Spallation Neutron Source (SNS) at Oak Ridge as their principal facility partner. The SNS is a next-generation neutron source. It has completed construction at a cost of 1.4 billion and is ramping up operations. The SNS will provide an order of magnitude greater flux than any previous facility in the world and will be available to all of the nation's scientists, independent of funding source, on a peer-reviewed merit basis. With this new capability, the neutron science community is facing orders of magnitude larger data sets and is at a critical point for data analysis and simulation. There is a recognized need for new ways to manage and analyze data to optimize both beam time and scientific output. The TeraGrid is providing new capabilities in the gateway for simulations using McStas and a fitting service on distributed TeraGrid resources to improved turnaround. NSTG staff are also exploring replicating experimental data in archival storage. As part of the SNS partnership, the NSTG provides access to gateway support, cyberinfrastructure outreach, community development, and user support for the neutron science community. This community includes not only SNS staff and users but extends to all the major worldwide neutron scattering centers.

  4. Bridging Science and Public Understanding of Water-Energy Nexus: Opportunities for broader impact connections with InTeGrate

    NASA Astrophysics Data System (ADS)

    Orr, C. H.; Manduca, C. A.; Bruckner, M.

    2015-12-01

    Understanding trade-offs and interactions between water and energy is crucial in understanding many issues of sustainability faced by society in our changing environment. Increasing capcity through public literacy and preparing the future workforce to address these challenges are key goals of the NSF STEP Center InTeGrate. We connect teaching about the Earth to societal issues for undergraduates across the curriculum. Understanding the interaction between engineering, sustainability and the geosciences and the role engineering plays in building a sustainable future, in areas such resource and energy use is a major foci of our work. Connecting this knowledge to societal issues that undergraduates can relate to, and improving interdisciplinary problem-solving are needed in addressing the Grand Challenges facing society. The project features interdisciplinary materials that engage students in learning about the Earth by focusing on pressing topics and using evidence-based teaching practice. These materials are designed for both science and non-science majors at the undergraduate level and have been rigorously reviewed and tested in the classroom. Topics include Environmental Justice and Freshwater Resources, Interactions between Water, Earth's Surface and Human Activity, and Human's Dependence on Earth's Mineral Resources. Upcoming, new topics include modules on Energy Environment and Our Future, Global Energy and Atmosphere, Ecosystem Services Approach to Water Resources and course-length material on Grand Challenges of Interdisciplinary Water Sustainability and Gateway to Renewable Energy and Environmental Sustainability. We invite you to partner with the InTeGrate project as you think about broader impacts related to your work. Examples include creating a case study detailing your project and how faculty can use it in their classroom, contributing example activities that utilize your datasets, and more. Check out the site at: serc.carleton.edu/integrate/

  5. A Multi-Level Grid Interactive Bi-directional AC/DC-DC/AC Converter and a Hybrid Battery/Ultra-capacitor Energy Storage System with Integrated Magnetics for Plug-in Hybrid Electric Vehicles

    SciTech Connect

    Onar, Omer C

    2011-01-01

    This study presents a bi-directional multi-level power electronic interface for the grid interactions of plug-in hybrid electric vehicles (PHEVs) as well as a novel bi-directional power electronic converter for the combined operation of battery/ultracapacitor hybrid energy storage systems (ESS). The grid interface converter enables beneficial vehicle-to-grid (V2G) interactions in a high power quality and grid friendly manner; i.e, the grid interface converter ensures that all power delivered to/from grid has unity power factor and almost zero current harmonics. The power electronic converter that provides the combined operation of battery/ultra-capacitor system reduces the size and cost of the conventional ESS hybridization topologies while reducing the stress on the battery, prolonging the battery lifetime, and increasing the overall vehicle performance and efficiency. The combination of hybrid ESS is provided through an integrated magnetic structure that reduces the size and cost of the inductors of the ESS converters. Simulation and experimental results are included as prove of the concept presenting the different operation modes of the proposed converters.

  6. Integrating passive microwave remotely sensed imagery and gridded atmospheric data: A study of North American Prairie snow cover

    NASA Astrophysics Data System (ADS)

    Derksen, Christopher Peter

    Terrestrial snow cover is an important climatological variable because of its influence on the surface radiative balance, and a significant hydrological variable as it acts as the frozen storage term in the water balance. Satellite passive-microwave imagery has been used as a source of snow cover information because of all-weather imaging capabilities, rapid scene revisit time, and the ability to derive quantitative estimates of snow water equivalent (SWE). In this study, ten winter seasons (December, January, February 1988/89 to 1997/98) of five day averaged (pentad) passive-microwave derived SWE imagery are utilized to examine the seasonal snow cover characteristics of a ground-validated North American Prairie study area. Four dominant patterns are identified within the DeltaSWE time series. The positive (negative) phase of PC1 captures a pattern of widespread SWE ablation (accumulation) in the south with accumulation (ablation) to the north. The positive (negative) phase of PC2 characterizes a meridional accumulation (ablation) zone oriented from the northwest to southeast of the study area. The positive (negative) phase of PC3 indicates a regional melt event (accumulation event) in the lee of the Rocky Mountains. Finally, the positive (negative) phase of PC4 characterizes increasing (decreasing) SWE in the vicinity of the Red River Valley. National Center for Environmental Prediction (NCEP) gridded atmospheric data (500 mb geopotential height; 700 mb temperature) and model produced isentropic potential vorticity (IPV) fields are investigated in conjunction with the first four DeltaSWE principal components to identify whether consistency exists in the atmospheric patterns associated, at no time lag, with these dominant DeltaSWE modes. When a deep eastern Arctic low with an associated trough extends over the continental interior of North America, snow accumulation is the expected response (as characterized DeltaSWE PC1 positive, PC2 positive, and PC4 positive

  7. From the grid to the smart grid, topologically

    NASA Astrophysics Data System (ADS)

    Pagani, Giuliano Andrea; Aiello, Marco

    2016-05-01

    In its more visionary acceptation, the smart grid is a model of energy management in which the users are engaged in producing energy as well as consuming it, while having information systems fully aware of the energy demand-response of the network and of dynamically varying prices. A natural question is then: to make the smart grid a reality will the distribution grid have to be upgraded? We assume a positive answer to the question and we consider the lower layers of medium and low voltage to be the most affected by the change. In our previous work, we analyzed samples of the Dutch distribution grid (Pagani and Aiello, 2011) and we considered possible evolutions of these using synthetic topologies modeled after studies of complex systems in other technological domains (Pagani and Aiello, 2014). In this paper, we take an extra important step by defining a methodology for evolving any existing physical power grid to a good smart grid model, thus laying the foundations for a decision support system for utilities and governmental organizations. In doing so, we consider several possible evolution strategies and apply them to the Dutch distribution grid. We show how increasing connectivity is beneficial in realizing more efficient and reliable networks. Our proposal is topological in nature, enhanced with economic considerations of the costs of such evolutions in terms of cabling expenses and economic benefits of evolving the grid.

  8. Information Power Grid Posters

    NASA Technical Reports Server (NTRS)

    Vaziri, Arsi

    2003-01-01

    This document is a summary of the accomplishments of the Information Power Grid (IPG). Grids are an emerging technology that provide seamless and uniform access to the geographically dispersed, computational, data storage, networking, instruments, and software resources needed for solving large-scale scientific and engineering problems. The goal of the NASA IPG is to use NASA's remotely located computing and data system resources to build distributed systems that can address problems that are too large or complex for a single site. The accomplishments outlined in this poster presentation are: access to distributed data, IPG heterogeneous computing, integration of large-scale computing node into distributed environment, remote access to high data rate instruments,and exploratory grid environment.

  9. A computer software system for integration and analysis of grid-based remote sensing data with other natural resource data

    NASA Technical Reports Server (NTRS)

    Tilmann, S. E.; Enslin, W. R.; Hill-Rowley, R.

    1977-01-01

    This report describes a computer-based information system designed to assist in the integration of commonly available spatial data for regional planning and resource analysis. The Resource Analysis Program (RAP) provides a variety of analytical and mapping phases for single factor or multi-factor analyses. The unique analytical and graphic capabilities of RAP are demonstrated with a study conducted in Windsor Township, Eaton County, Michigan. For this study, soil, land cover/use, topographic and geological maps were used as a data base to develop an eleven map portfolio. The major themes of the portfolio are land cover/use, nonpoint water pollution, waste disposal, and ground water recharge.

  10. How Extended Is Wernicke's Area? Meta-Analytic Connectivity Study of BA20 and Integrative Proposal.

    PubMed

    Ardila, Alfredo; Bernal, Byron; Rosselli, Monica

    2016-01-01

    Understanding the functions of different brain areas has represented a major endeavor of contemporary neurosciences. The purpose of this paper was to pinpoint the connectivity of Brodmann area 20 (BA20) (inferior temporal gyrus, fusiform gyrus) in language tasks. A meta-analysis was conducted to assess the language network in which BA20 is involved. The DataBase of Brainmap was used; 11 papers corresponding to 12 experimental conditions with a total of 207 subjects were included in this analysis. Our results demonstrated seven clusters of activation including other temporal lobe areas (BA3, BA21), the insula, and the prefrontal cortex; minor clusters in the cingulate gyrus and the occipital lobe were observed; however, the volumes of all the activation clusters were small. Our results suggest that regardless of BA20 having certain participation in language processes it cannot be considered as a core language processing area (Wernicke's area); nonetheless, it could be regarded as kind of language processing marginal area, participating in "extended Wernicke's area" or simply "Wernicke's system." It is suggested that "core Wernicke's area" roughly corresponds to BA21, BA22, BA41, and BA42, while a "language associations area" roughly corresponds to BA20, BA37, BA38, BA39, and BA40 ("extended Wernicke's area" or "Wernicke's system"). PMID:27006905

  11. How Extended Is Wernicke's Area? Meta-Analytic Connectivity Study of BA20 and Integrative Proposal

    PubMed Central

    Bernal, Byron

    2016-01-01

    Understanding the functions of different brain areas has represented a major endeavor of contemporary neurosciences. The purpose of this paper was to pinpoint the connectivity of Brodmann area 20 (BA20) (inferior temporal gyrus, fusiform gyrus) in language tasks. A meta-analysis was conducted to assess the language network in which BA20 is involved. The DataBase of Brainmap was used; 11 papers corresponding to 12 experimental conditions with a total of 207 subjects were included in this analysis. Our results demonstrated seven clusters of activation including other temporal lobe areas (BA3, BA21), the insula, and the prefrontal cortex; minor clusters in the cingulate gyrus and the occipital lobe were observed; however, the volumes of all the activation clusters were small. Our results suggest that regardless of BA20 having certain participation in language processes it cannot be considered as a core language processing area (Wernicke's area); nonetheless, it could be regarded as kind of language processing marginal area, participating in “extended Wernicke's area” or simply “Wernicke's system.” It is suggested that “core Wernicke's area” roughly corresponds to BA21, BA22, BA41, and BA42, while a “language associations area” roughly corresponds to BA20, BA37, BA38, BA39, and BA40 (“extended Wernicke's area” or “Wernicke's system”). PMID:27006905

  12. Making student connections with the carbon cycle: Integrating science, public outreach, and education

    NASA Astrophysics Data System (ADS)

    Wood, J.; Natali, S.

    2013-12-01

    Outreach collaborations have been on going over the past three years bringing current field science into the classroom, supporting STEM education through lessons and professional development, and creating lasting connections between research and education. Utilizing the PolarTREC model and support, Dr. Susan Natali, from the Woods Hole Research Center, and Mr. John Wood, from the Fountain Valley School District in Orange County California, have successfully engaged research personnel and classroom students in experiments looking into the warming and drying of tundra in central Alaska. During that time both Natali and Wood have challenged local students at the field site near Healy, Alaska as well as conducted activities with California students at Talbert Middle School. Using the on-line PolarTREC tools students have followed research activities through daily journal entries, including more than one thousand posted questions and responses, and participating in webinars. In addition, Dr. Natali and members of her team have traveled to Talbert with their instruments where students replicated experiments from Alaska while designing and constructing their own sets of experiments based on the carbon cycle models from the tundra. This collaboration and outreach partnership continues to engage students and scientists throughout the Fountain Valley School District and beyond, as well as including on going research efforts in Alaska and Siberia by Dr. Natali and her team. Dr. Natali engages Talbert students in California while collecting carbon dioxide data. PolarTREC teacher John Wood works with local Alaskan students to understand carbon cycling in the tundra.

  13. LAPS Grid generation and adaptation

    NASA Astrophysics Data System (ADS)

    Pagliantini, Cecilia; Delzanno, Gia Luca; Guo, Zehua; Srinivasan, Bhuvana; Tang, Xianzhu; Chacon, Luis

    2011-10-01

    LAPS uses a common-data framework in which a general purpose grid generation and adaptation package in toroidal and simply connected domains is implemented. The initial focus is on implementing the Winslow/Laplace-Beltrami method for generating non-overlapping block structured grids. This is to be followed by a grid adaptation scheme based on Monge-Kantorovich optimal transport method [Delzanno et al., J. Comput. Phys,227 (2008), 9841-9864], that equidistributes application-specified error. As an initial set of applications, we will lay out grids for an axisymmetric mirror, a field reversed configuration, and an entire poloidal cross section of a tokamak plasma reconstructed from a CMOD experimental shot. These grids will then be used for computing the plasma equilibrium and transport in accompanying presentations. A key issue for Monge-Kantorovich grid optimization is the choice of error or monitor function for equi-distribution. We will compare the Operator Recovery Error Source Detector (ORESD) [Lapenta, Int. J. Num. Meth. Eng,59 (2004) 2065-2087], the Tau method and a strategy based on the grid coarsening [Zhang et al., AIAA J,39 (2001) 1706-1715] to find an ``optimal'' grid. Work supported by DOE OFES.

  14. Telomeric repeat-containing RNA TERRA: a noncoding RNA connecting telomere biology to genome integrity.

    PubMed

    Cusanelli, Emilio; Chartrand, Pascal

    2015-01-01

    Telomeres are dynamic nucleoprotein structures that protect the ends of chromosomes from degradation and activation of DNA damage response. For this reason, telomeres are essential to genome integrity. Chromosome ends are enriched in heterochromatic marks and proper organization of telomeric chromatin is important to telomere stability. Despite their heterochromatic state, telomeres are transcribed giving rise to long noncoding RNAs (lncRNA) called TERRA (telomeric repeat-containing RNA). TERRA molecules play critical roles in telomere biology, including regulation of telomerase activity and heterochromatin formation at chromosome ends. Emerging evidence indicate that TERRA transcripts form DNA-RNA hybrids at chromosome ends which can promote homologous recombination among telomeres, delaying cellular senescence and sustaining genome instability. Intriguingly, TERRA RNA-telomeric DNA hybrids are involved in telomere length homeostasis of telomerase-negative cancer cells. Furthermore, TERRA transcripts play a role in the DNA damage response (DDR) triggered by dysfunctional telomeres. We discuss here recent developments on TERRA's role in telomere biology and genome integrity, and its implication in cancer.

  15. Multi-chimera states and transitions in the Leaky Integrate-and-Fire model with nonlocal and hierarchical connectivity

    NASA Astrophysics Data System (ADS)

    Tsigkri-DeSmedt, N. D.; Hizanidis, J.; Hövel, P.; Provata, A.

    2016-09-01

    The effects of nonlocal and fractal connectivity are investigated in a network of Leaky Integrate-and-Fire (LIF) elements. The idea of fractal coupling originates from the hierarchical topology of networks formed by neuronal axons, which transmit the electrical signals in the brain. If a number of LIF elements with finite refractory period are nonlocally coupled, multi-chimera states emerge whose multiplicity depends both on the coupling strength and on the refractory period. We provide evidence that the introduction of a hierarchical topology in the coupling induces novel complex spatial and temporal structures, such as nested chimera states and transitions between multi-chimera states with different multiplicities. These results demonstrate new complex patterns, as well as transitions between different multi-chimera states arising from the combination of nonlinear dynamics with the hierarchical coupling.

  16. NSTAR Smart Grid Pilot

    SciTech Connect

    Rabari, Anil; Fadipe, Oloruntomi

    2014-03-31

    NSTAR Electric & Gas Corporation (“the Company”, or “NSTAR”) developed and implemented a Smart Grid pilot program beginning in 2010 to demonstrate the viability of leveraging existing automated meter reading (“AMR”) deployments to provide much of the Smart Grid functionality of advanced metering infrastructure (“AMI”), but without the large capital investment that AMI rollouts typically entail. In particular, a central objective of the Smart Energy Pilot was to enable residential dynamic pricing (time-of-use “TOU” and critical peak rates and rebates) and two-way direct load control (“DLC”) by continually capturing AMR meter data transmissions and communicating through customer-sited broadband connections in conjunction with a standardsbased home area network (“HAN”). The pilot was supported by the U.S. Department of Energy’s (“DOE”) through the Smart Grid Demonstration program. NSTAR was very pleased to not only receive the funding support from DOE, but the guidance and support of the DOE throughout the pilot. NSTAR is also pleased to report to the DOE that it was able to execute and deliver a successful pilot on time and on budget. NSTAR looks for future opportunities to work with the DOE and others in future smart grid projects.

  17. Grid reliability

    NASA Astrophysics Data System (ADS)

    Saiz, P.; Andreeva, J.; Cirstoiu, C.; Gaidioz, B.; Herrala, J.; Maguire, E. J.; Maier, G.; Rocha, R.

    2008-07-01

    Thanks to the Grid, users have access to computing resources distributed all over the world. The Grid hides the complexity and the differences of its heterogeneous components. In such a distributed system, it is clearly very important that errors are detected as soon as possible, and that the procedure to solve them is well established. We focused on two of its main elements: the workload and the data management systems. We developed an application to investigate the efficiency of the different centres. Furthermore, our system can be used to categorize the most common error messages, and control their time evolution.

  18. No Reef Is an Island: Integrating Coral Reef Connectivity Data into the Design of Regional-Scale Marine Protected Area Networks

    PubMed Central

    Schill, Steven R.; Raber, George T.; Roberts, Jason J.; Treml, Eric A.; Brenner, Jorge; Halpin, Patrick N.

    2015-01-01

    We integrated coral reef connectivity data for the Caribbean and Gulf of Mexico into a conservation decision-making framework for designing a regional scale marine protected area (MPA) network that provides insight into ecological and political contexts. We used an ocean circulation model and regional coral reef data to simulate eight spawning events from 2008–2011, applying a maximum 30-day pelagic larval duration and 20% mortality rate. Coral larval dispersal patterns were analyzed between coral reefs across jurisdictional marine zones to identify spatial relationships between larval sources and destinations within countries and territories across the region. We applied our results in Marxan, a conservation planning software tool, to identify a regional coral reef MPA network design that meets conservation goals, minimizes underlying threats, and maintains coral reef connectivity. Our results suggest that approximately 77% of coral reefs identified as having a high regional connectivity value are not included in the existing MPA network. This research is unique because we quantify and report coral larval connectivity data by marine ecoregions and Exclusive Economic Zones (EZZ) and use this information to identify gaps in the current Caribbean-wide MPA network by integrating asymmetric connectivity information in Marxan to design a regional MPA network that includes important reef network connections. The identification of important reef connectivity metrics guides the selection of priority conservation areas and supports resilience at the whole system level into the future. PMID:26641083

  19. Analyzing urban sub-grid processes using high-resolution land cover and an integrated hydrologic model

    NASA Astrophysics Data System (ADS)

    Reyes, B.; Maxwell, R. M.; Hogue, T. S.

    2014-12-01

    As the world rapidly urbanizes, a grasp of water resources within an urban context becomes crucial to both the policy and scientific communities. Parameterizing and understanding the interactions between the land surface and terrestrial hydrologic budgets of the urban domain within watershed and regional models is critical to this goal. The work presented here assesses the processes simulated by an integrated, coupled land surface/hydrologic model at various spatial scales in the urban domain as well as the changes in partitioning of runoff and evapotranspiration (ET) as a function of land cover heterogeneity. Two land cover datasets for the City of Los Angeles are utilized: (1) the National Land Cover Database (NLCD) dataset at a 30-m resolution that categorizes the urban domain between developed open space, and low, medium and high intensity developed land cover; and (2) an ultra high-resolution dataset that classifies the City into grass, tree, bare soil, and impervious land cover at a 0.6-m resolution. Using these datasets and hourly observed meteorological forcings, we simulate various permutations and resolutions ranging from 0.6-m to 30-m for a two year spin-up and two year study period. Our analyses shows that increasing resolution alone, while holding all other parameters constant, greatly changes timing of hydrologic events and the overall hydrologic budget with higher resolutions producing less overland flow than lower resolution models. The impact of the highly organized, yet heterogeneous, land cover typical of the urban domain is also assessed. The runoff/runon processes characteristic of these domains create variations in overland flow of up to ±20% and ±3% in ET. Finally, the impact of scaling land surface and hydrologic parameters is shown to create systematic diurnal biases in the surface energy budget in contrast to the seasonal biases seen in the hydrologic fluxes. This work, in addition to creating land surface parameters for the widely used

  20. OGC and Grid Interoperability in enviroGRIDS Project

    NASA Astrophysics Data System (ADS)

    Gorgan, Dorian; Rodila, Denisa; Bacu, Victor; Giuliani, Gregory; Ray, Nicolas

    2010-05-01

    the OGC Web service protocols, the advantages offered by the Grid technology - such as providing a secure interoperability between the distributed geospatial resource -and the issues introduced by the integration of distributed geospatial data in a secure environment: data and service discovery, management, access and computation. enviroGRIDS project proposes a new architecture which allows a flexible and scalable approach for integrating the geospatial domain represented by the OGC Web services with the Grid domain represented by the gLite middleware. The parallelism offered by the Grid technology is discussed and explored at the data level, management level and computation level. The analysis is carried out for OGC Web service interoperability in general but specific details are emphasized for Web Map Service (WMS), Web Feature Service (WFS), Web Coverage Service (WCS), Web Processing Service (WPS) and Catalog Service for Web (CSW). Issues regarding the mapping and the interoperability between the OGC and the Grid standards and protocols are analyzed as they are the base in solving the communication problems between the two environments: grid and geospatial. The presetation mainly highlights how the Grid environment and Grid applications capabilities can be extended and utilized in geospatial interoperability. Interoperability between geospatial and Grid infrastructures provides features such as the specific geospatial complex functionality and the high power computation and security of the Grid, high spatial model resolution and geographical area covering, flexible combination and interoperability of the geographical models. According with the Service Oriented Architecture concepts and requirements of interoperability between geospatial and Grid infrastructures each of the main functionality is visible from enviroGRIDS Portal and consequently, by the end user applications such as Decision Maker/Citizen oriented Applications. The enviroGRIDS portal is the single way

  1. Role of Storage and Demand Response, Greening the Grid

    SciTech Connect

    2015-09-01

    Greening the Grid provides technical assistance to energy system planners, regulators, and grid operators to overcome challenges associated with integrating variable renewable energy into the grid. This document, part of a Greening the Grid toolkit, examines storage and demand response as means to match renewable energy supply with demand.

  2. Methods for Procuring Power System Flexibility, Greening the Grid

    SciTech Connect

    Katz, Jessica; Cochran, Jaquelin; Miller, Mackay

    2015-05-01

    Greening the Grid provides technical assistance to energy system planners, regulators, and grid operators to overcome challenges associated with integrating variable renewable energy into the grid. This document, part of a Greening the Grid toolkit, introduces administrative and incentive-based mechanisms for procuring a cost-effective mix of flexibility sources.

  3. Changes in the integrity of thalamocortical connections are associated with sensorimotor deficits in children with congenital hemiplegia.

    PubMed

    Tsao, Henry; Pannek, Kerstin; Boyd, Roslyn N; Rose, Stephen E

    2015-01-01

    Preservation of thalamocortical projections to the sensorimotor cortex is related to improved hand function in children with cerebral palsy (CP). Whether CP is associated with altered microstructure of these sensorimotor projections or other thalamocortical pathways remains unclear. Forty-two children with congenital hemiplegia and fifteen typically developing children (TDC) underwent structural and diffusion-weighted imaging (high-angular-resolution diffusion imaging) using a 3T MRI. Structural T1-images were parcellated into 34 cortical regions and the thalamus per hemisphere. Thalamocortical projections were extracted using probabilistic tractography and the top tan cortical regions with the greatest number of thalamocortical streamlines for the TDC group were selected for further analysis. The thalamus was parcellated based on its cortical connections. Differences between hemispheres for thalamocortical streamline numbers to each cortical region [asymmetry index (AI)], tract volume and tract microstructure [weighted mean fractional anisotropy (FA) and mean diffusivity (MD)] were calculated. Correlations between these measures (AI, FA and MD) and sensorimotor function were performed. Thalamocortical projections showed topographical organisation based on cortical connectivity. Projections to paracentral lobule, pre-central and post-central gyri showed greater AI in CP group, which indicates reduced streamlines on the ipsilesioned hemisphere. Reduced FA, reduced tract volume and increased MD were also found for these thalamocortical projections on the ipsilesioned hemisphere in children with CP. Changes in AI and tract microstructure of these projections were associated with poorer sensorimotor function. The findings suggest CP is associated with reorganisation of thalamocortical projections to the sensorimotor cortex. Integrity in these projections may underpin deficits in sensorimotor function. PMID:24146132

  4. Maturity Model for Advancing Smart Grid Interoperability

    SciTech Connect

    Knight, Mark; Widergren, Steven E.; Mater, J.; Montgomery, Austin

    2013-10-28

    Abstract—Interoperability is about the properties of devices and systems to connect and work properly. Advancing interoperability eases integration and maintenance of the resulting interconnection. This leads to faster integration, lower labor and component costs, predictability of projects and the resulting performance, and evolutionary paths for upgrade. When specifications are shared and standardized, competition and novel solutions can bring new value streams to the community of stakeholders involved. Advancing interoperability involves reaching agreement for how things join at their interfaces. The quality of the agreements and the alignment of parties involved in the agreement present challenges that are best met with process improvement techniques. The GridWise® Architecture Council (GWAC) sponsored by the United States Department of Energy is supporting an effort to use concepts from capability maturity models used in the software industry to advance interoperability of smart grid technology. An interoperability maturity model has been drafted and experience is being gained through trials on various types of projects and community efforts. This paper describes the value and objectives of maturity models, the nature of the interoperability maturity model and how it compares with other maturity models, and experiences gained with its use.

  5. Parallel Power Grid Simulation Toolkit

    SciTech Connect

    Smith, Steve; Kelley, Brian; Banks, Lawrence; Top, Philip; Woodward, Carol

    2015-09-14

    ParGrid is a 'wrapper' that integrates a coupled Power Grid Simulation toolkit consisting of a library to manage the synchronization and communication of independent simulations. The included library code in ParGid, named FSKIT, is intended to support the coupling multiple continuous and discrete even parallel simulations. The code is designed using modern object oriented C++ methods utilizing C++11 and current Boost libraries to ensure compatibility with multiple operating systems and environments.

  6. An adaptive discretization of compressible flow using a multitude of moving Cartesian grids

    NASA Astrophysics Data System (ADS)

    Qiu, Linhai; Lu, Wenlong; Fedkiw, Ronald

    2016-01-01

    We present a novel method for simulating compressible flow on a multitude of Cartesian grids that can rotate and translate. Following previous work, we split the time integration into an explicit step for advection followed by an implicit solve for the pressure. A second order accurate flux based scheme is devised to handle advection on each moving Cartesian grid using an effective characteristic velocity that accounts for the grid motion. In order to avoid the stringent time step restriction imposed by very fine grids, we propose strategies that allow for a fluid velocity CFL number larger than 1. The stringent time step restriction related to the sound speed is alleviated by formulating an implicit linear system in order to find a pressure consistent with the equation of state. This implicit linear system crosses overlapping Cartesian grid boundaries by utilizing local Voronoi meshes to connect the various degrees of freedom obtaining a symmetric positive-definite system. Since a straightforward application of this technique contains an inherent central differencing which can result in spurious oscillations, we introduce a new high order diffusion term similar in spirit to ENO-LLF but solved for implicitly in order to avoid any associated time step restrictions. The method is conservative on each grid, as well as globally conservative on the background grid that contains all other grids. Moreover, a conservative interpolation operator is devised for conservatively remapping values in order to keep them consistent across different overlapping grids. Additionally, the method is extended to handle two-way solid fluid coupling in a monolithic fashion including cases (in the appendix) where solids in close proximity do not properly allow for grid based degrees of freedom in between them.

  7. Safe Grid

    NASA Technical Reports Server (NTRS)

    Chow, Edward T.; Stewart, Helen; Korsmeyer, David (Technical Monitor)

    2003-01-01

    The biggest users of GRID technologies came from the science and technology communities. These consist of government, industry and academia (national and international). The NASA GRID is moving into a higher technology readiness level (TRL) today; and as a joint effort among these leaders within government, academia, and industry, the NASA GRID plans to extend availability to enable scientists and engineers across these geographical boundaries collaborate to solve important problems facing the world in the 21 st century. In order to enable NASA programs and missions to use IPG resources for program and mission design, the IPG capabilities needs to be accessible from inside the NASA center networks. However, because different NASA centers maintain different security domains, the GRID penetration across different firewalls is a concern for center security people. This is the reason why some IPG resources are been separated from the NASA center network. Also, because of the center network security and ITAR concerns, the NASA IPG resource owner may not have full control over who can access remotely from outside the NASA center. In order to obtain organizational approval for secured remote access, the IPG infrastructure needs to be adapted to work with the NASA business process. Improvements need to be made before the IPG can be used for NASA program and mission development. The Secured Advanced Federated Environment (SAFE) technology is designed to provide federated security across NASA center and NASA partner's security domains. Instead of one giant center firewall which can be difficult to modify for different GRID applications, the SAFE "micro security domain" provide large number of professionally managed "micro firewalls" that can allow NASA centers to accept remote IPG access without the worry of damaging other center resources. The SAFE policy-driven capability-based federated security mechanism can enable joint organizational and resource owner approved remote

  8. A general multiblock Euler code for propulsion integration. Volume 2: User guide for BCON, pre-processor for grid generation and GMBE

    NASA Technical Reports Server (NTRS)

    Su, T. Y.; Appleby, R. A.; Chen, H. C.

    1991-01-01

    The BCON is a menu-driven graphics interface program whose input consists of strings or arrays of points generated from a computer aided design (CAD) tool or any other surface geometry source. The user needs to design the block topology and prepare the surface geometry definition and surface grids separately. The BCON generates input files that contain the block definitions and the block relationships required for generating a multiblock volume grid with the EAGLE grid generation package. The BCON also generates the block boundary conditions file which is used along with the block relationship file as input for the general multiblock Euler (GMBE) code (GMBE, volumes 1 and 3).

  9. Ion mobility spectrometer with virtual aperture grid

    DOEpatents

    Pfeifer, Kent B.; Rumpf, Arthur N.

    2010-11-23

    An ion mobility spectrometer does not require a physical aperture grid to prevent premature ion detector response. The last electrodes adjacent to the ion collector (typically the last four or five) have an electrode pitch that is less than the width of the ion swarm and each of the adjacent electrodes is connected to a source of free charge, thereby providing a virtual aperture grid at the end of the drift region that shields the ion collector from the mirror current of the approaching ion swarm. The virtual aperture grid is less complex in assembly and function and is less sensitive to vibrations than the physical aperture grid.

  10. Image enhancement with polymer grid triode arrays

    SciTech Connect

    Heeger, A.J.; Heeger, D.J.; Langan, J.

    1995-12-08

    An array of polymer grid triodes connected by a common grid functions as a {open_quotes}plastic retina,{close_quotes} providing local contrast gain control for image enhancement. This simple device, made from layers of conducting polymers, functions as an active resistive network that performs center-surround filtering. The polymer grid triode array with common grid is a continuous analog of the discrete approach of Mead, with a variety of fabrication advantages and significant savings in area within the unit cell of each pixel. 6 refs., 4 figs.

  11. Integrated connection to neighborhood storytelling network, education, and chronic disease knowledge among African Americans and Latinos in Los Angeles.

    PubMed

    Kim, Yong-Chan; Moran, Meghan B; Wilkin, Holley A; Ball-Rokeach, Sandra J

    2011-04-01

    Combining key ideas from the knowledge-gap hypothesis and communication infrastructure theory, the present study aimed to explain the relations among individuals' education, access to community-based communication resources, and knowledge of chronic diseases (diabetes, hypertension, breast cancer, and prostate cancer) among African Americans and Latinos in Los Angeles. Rather than explore the effect of isolated communication resources, this study explored the effect of an integrated connection to community-based storytellers on chronic disease knowledge. The authors hypothesized that individuals' access to a community-based communication infrastructure for obtaining and sharing information functions as an intervening step in the process where social inequality factors such as education lead to chronic disease knowledge gaps in a local community context. With random samples of African Americans and Latinos in Los Angeles, the authors found that access to community-based communication resources plays a mediating role in the case of breast cancer and diabetes knowledge, but not in hypertension and prostate cancer knowledge. The authors discussed these findings on the basis of communication infrastructure theory and knowledge-gap hypothesis. PMID:21302173

  12. PNNL Data-Intensive Computing for a Smarter Energy Grid

    ScienceCinema

    Carol Imhoff; Zhenyu (Henry) Huang; Daniel Chavarria

    2016-07-12

    The Middleware for Data-Intensive Computing (MeDICi) Integration Framework, an integrated platform to solve data analysis and processing needs, supports PNNL research on the U.S. electric power grid. MeDICi is enabling development of visualizations of grid operations and vulnerabilities, with goal of near real-time analysis to aid operators in preventing and mitigating grid failures.

  13. Network-theoretical approach to partitioning of real power grids

    NASA Astrophysics Data System (ADS)

    Abou Hamad, Ibrahim; Israels, Brett; Poroseva, Svetlana V.; Rikvold, Per Arne

    2010-03-01

    Modern societies depend critically on their electrical power grids. It is, therefore, essential to understand the grid's large-scale behavior in order to improve its resilience against catastrophic damage. A key factor determining the grid's large-scale behavior is its topology. In particular, an important question is whether a grid topology can be efficiently partitioned into independent communities (``islands'') of densely connected vertices (generators, substations, consumers) that are more loosely connected to other communities. Such partitioning can be utilized either to strengthen the grid by introducing new connections, or to achieve ``Intentional Intelligent Islanding'' by installing control devices in a minimal number of links in order to contain cascading failures to a limited region. Here we report on the performance of several network-partitioning algorithms, both agglomerative and spectral-based divisive, in applications to real power grids, including the high-voltage grids of Florida and Italy.

  14. The role of water and sediment connectivity in integrated flood management: a case study on the island of Saint Lucia

    NASA Astrophysics Data System (ADS)

    Jetten, Victor; van Westen, Cees; Ettema, Janneke; van den Bout, Bastian

    2016-04-01

    flood potential considerably during the event, and if not cleared properly during the next event. To understand this it is essential to simulate the catchment as one integrated unit, study connectivity and sources and sinks. We will show how from these simulations, how sustainable hazard and risk reduction strategies can be derived. The example comes from the Worldbank technical assistance project CHARIM, that is currently conducted by the University of Twente (the Netherlands), University of Bristol, (UK) and the University of the West Indies (Trinidad and Tobago) in 4 Caribbean islands and Belize.

  15. GridOPTICS Software System

    2014-02-24

    GridOPTICS Software System (GOSS) is a middleware that facilitates creation of new, modular and flexible operational and planning platforms that can meet the challenges of the next generation power grid. GOSS enables Department of Energy, power system utilities, and vendors to build better tools faster. GOSS makes it possible to integrate Future Power Grid Initiative software products/prototypes into existing power grid software systems, including the PNNL PowerNet and EIOC environments. GOSS is designed to allowmore » power grid applications developed for different underlying software platforms installed in different utilities to communicate with ease. This can be done in compliance with existing security and data sharing policies between the utilities. GOSS not only supports one-to-one data transfer between applications, but also publisher/subscriber scheme. To support interoperability requirements of future EMS, GOSS is designed for CIM compliance. In addition to this, it supports authentication and authorization capabilities to protect the system from cyber threats. In summary, the contributions of the GOSS middleware are as follows: • A platform to support future EMS development. • A middleware that promotes interoperability between power grid applications. • A distributed architecture that separates data sources from power grid applications. • Support for data exchange with either one-to-one or publisher/subscriber interfaces. • An authentication and authorization scheme for limiting the access to data between utilities.« less

  16. GridOPTICS Software System

    SciTech Connect

    Akyol, Bora A; Ciraci, PNNL Selim; Gibson, PNNL Tara; Rice, PNNL Mark; Sharma, PNNL Poorva; Yin, PNNL Jian; Allwardt, PNNL Craig; PNNL,

    2014-02-24

    GridOPTICS Software System (GOSS) is a middleware that facilitates creation of new, modular and flexible operational and planning platforms that can meet the challenges of the next generation power grid. GOSS enables Department of Energy, power system utilities, and vendors to build better tools faster. GOSS makes it possible to integrate Future Power Grid Initiative software products/prototypes into existing power grid software systems, including the PNNL PowerNet and EIOC environments. GOSS is designed to allow power grid applications developed for different underlying software platforms installed in different utilities to communicate with ease. This can be done in compliance with existing security and data sharing policies between the utilities. GOSS not only supports one-to-one data transfer between applications, but also publisher/subscriber scheme. To support interoperability requirements of future EMS, GOSS is designed for CIM compliance. In addition to this, it supports authentication and authorization capabilities to protect the system from cyber threats. In summary, the contributions of the GOSS middleware are as follows: • A platform to support future EMS development. • A middleware that promotes interoperability between power grid applications. • A distributed architecture that separates data sources from power grid applications. • Support for data exchange with either one-to-one or publisher/subscriber interfaces. • An authentication and authorization scheme for limiting the access to data between utilities.

  17. BREAKUP. Prepares Overset Grids for Processing

    SciTech Connect

    Barnette, D.W.; Ober, C.C.

    1996-02-01

    Many large and complex computational problems require multiple, structured, generically overlapped (overset) grids to obtain numerical solutions in a timely manner. BREAKUP significantly reduces required compute times by preparing overset grids for processing on massively parallel computers. BREAKUP subdivides the original grids for use on a user-specified number of parallel processors. Grid-to-grid and intragrid communications are maintained in the parallel environment via connectivity tables generated by BREAKUP. The subgrids are formed to be statically load balanced and to incur a minimum of communication between the subgrids. When the output of BREAKUP is submitted to an appropriately modified flow solver, subgrid solutions will be updated simultaneously. This contrasts to the much less efficient solution method of updating each original grid sequentially as done in the past.

  18. Unstructured grid generation using the distance function

    NASA Technical Reports Server (NTRS)

    Bihari, Barna L.; Chakravarthy, Sukumar R.

    1991-01-01

    A new class of methods for obtaining level sets to generate unstructured grids is presented. The consecutive grid levels are computed using the distance functions, which corresponds to solving the Hamilton-Jacobi equations representing the equations of motion of fronts propagating with curvature-dependent speed. The relationship between the distance function and the governing equations will be discussed as well as its application to generating grids. Multi-ply connected domains and complex geometries are handled naturally, with a straightforward generalization to several space dimensions. The grid points for the unstructured grid are obtained simultaneously with the grid levels. The search involved in checking for overlapping triangles is minimized by triangulating the entire domain one level at a time.

  19. Custom Sky-Image Mosaics from NASA's Information Power Grid

    NASA Technical Reports Server (NTRS)

    Jacob, Joseph; Collier, James; Craymer, Loring; Curkendall, David

    2005-01-01

    yourSkyG is the second generation of the software described in yourSky: Custom Sky-Image Mosaics via the Internet (NPO-30556), NASA Tech Briefs, Vol. 27, No. 6 (June 2003), page 45. Like its predecessor, yourSkyG supplies custom astronomical image mosaics of sky regions specified by requesters using client computers connected to the Internet. Whereas yourSky constructs mosaics on a local multiprocessor system, yourSkyG performs the computations on NASA s Information Power Grid (IPG), which is capable of performing much larger mosaicking tasks. (The IPG is high-performance computation and data grid that integrates geographically distributed 18 NASA Tech Briefs, September 2005 computers, databases, and instruments.) A user of yourSkyG can specify parameters describing a mosaic to be constructed. yourSkyG then constructs the mosaic on the IPG and makes it available for downloading by the user. The complexities of determining which input images are required to construct a mosaic, retrieving the required input images from remote sky-survey archives, uploading the images to the computers on the IPG, performing the computations remotely on the Grid, and downloading the resulting mosaic from the Grid are all transparent to the user

  20. GridOPTICS(TM): A Design for Plug-and-Play Smart Grid Software Architecture

    SciTech Connect

    Gorton, Ian; Liu, Yan; Yin, Jian

    2012-06-03

    As the smart grid becomes reality, software architectures for integrating legacy systems with new innovative approaches for grid management are needed. These architectures must exhibit flexibility, extensibility, interoperability and scalability. In this position paper, we describe our preliminary work to design such an architecture, known as GridOPTICS, that will enable the deployment and integration of new software tools in smart grid operations. Our preliminary design is based upon use cases from PNNL’s Future Power Grid Initiative, which is a developing a collection of advanced software technologies for smart grid management and control. We describe the motivations for GridOPTICS, and the preliminary design that we are currently prototyping for several distinct use cases.

  1. Grid cells correlation structure suggests organized feedforward projections into superficial layers of the medial entorhinal cortex.

    PubMed

    Tocker, Gilad; Barak, Omri; Derdikman, Dori

    2015-12-01

    Navigation requires integration of external and internal inputs to form a representation of location. Part of this integration is considered to be carried out by the grid cells network in the medial entorhinal cortex (MEC). However, the structure of this neural network is unknown. To shed light on this structure, we measured noise correlations between 508 pairs of simultaneous previously recorded grid cells. We differentiated between pure grid and conjunctive cells (pure grid in Layers II, III, and VI vs. conjunctive in Layers III and V--only Layer III was bi-modal), and devised a new method to classify cell pairs as belonging/not-belonging to the same module. We found that pairs from the same module show significantly more correlations than pairs from different modules. The correlations between pure grid cells decreased in strength as their relative spatial phase increased. However, correlations were mostly at 0 time-lag, suggesting that the source of correlations was not only synaptic, but rather resulted mostly from common input. Given our measured correlations, the two functional groups of grid cells (pure vs. conjunctive), and the known disorganized recurrent connections within Layer II, we propose the following model: conjunctive cells in deep layers form an attractor network whose activity is governed by velocity-controlled signals. A second manifold in Layer II receives organized feedforward projections from the deep layers, giving rise to pure grid cells. Numerical simulations indicate that organized projections induce such correlations as we measure in superficial layers. Our results provide new evidence for the functional anatomy of the entorhinal circuit-suggesting that strong phase-organized feedforward projections support grid fields in the superficial layers.

  2. An interactive grid generation technique for fighter aircraft geometries

    NASA Technical Reports Server (NTRS)

    Smith, Robert E.; Everton, Eric L.

    1988-01-01

    This paper describes an interactive procedure to construct grids about fighter aircraft using a state-of-the-art workstation. The aircraft are characterized by a fuselage with an integrated canopy over the cockpit, an engine inlet, an area ruled midsection, canards, and highly-swept cranked delta wings or strakes integrated into the wings and tail surfaces. The grid topology, configuration surface grid, exterior grid computation, and computational interactive process are addressed.

  3. Systems Engineering Building Advances Power Grid Research

    SciTech Connect

    Virden, Jud; Huang, Henry; Skare, Paul; Dagle, Jeff; Imhoff, Carl; Stoustrup, Jakob; Melton, Ron; Stiles, Dennis; Pratt, Rob

    2015-08-19

    Researchers and industry are now better equipped to tackle the nation’s most pressing energy challenges through PNNL’s new Systems Engineering Building – including challenges in grid modernization, buildings efficiency and renewable energy integration. This lab links real-time grid data, software platforms, specialized laboratories and advanced computing resources for the design and demonstration of new tools to modernize the grid and increase buildings energy efficiency.

  4. Grid-connected distributed solar power systems

    NASA Astrophysics Data System (ADS)

    Moyle, R.; Chernoff, H.; Schweizer, T.

    This paper discusses some important, though often ignored, technical and economic issues of distributed solar power systems: protection of the utility system and nonsolar customers requires suitable interfaced equipment. Purchase criteria must mirror reality; most analyses use life-cycle costing with low discount rates - most buyers use short payback periods. Distributing, installing, and marketing small, distributed solar systems is more costly than most analyses estimate. Results show that certain local conditions and uncommon purchase considerations can combine to make small, distributed solar power attractive, but lower interconnect costs (per kW), lower marketing and product distribution costs, and more favorable purchase criteria make large, centralized solar energy more attractive. Specifically, the value of dispersed solar systems to investors and utilities can be higher than $2000/kw. However, typical residential owners place a value of well under $1000 on the installed system.

  5. Effects of massive wind power integration on short-term water resource management in central Chile - a grid-wide study

    NASA Astrophysics Data System (ADS)

    Haas, J.; Olivares, M. A.; Palma, R.

    2013-12-01

    In central Chile, water from reservoirs and streams is mainly used for irrigation and power generation. Hydropower reservoirs operation is particularly challenging because: i) decisions at each plant impact the entire power system, and ii) the existence of large storage capacity implies inter-temporal ties. An Independent System Operator (ISO) decides the grid-wide optimal allocation of water for power generation, under irrigation-related constraints. To account for the long-term opportunity cost of water, a future cost function is determined and used in the short term planning. As population growth and green policies demand increasing levels of renewable energy in power systems, deployment of wind farms and solar plants is rising quickly. However, their power output is highly fluctuating on short time scales, affecting the operation of power plants, particularly those fast responding units as hydropower reservoirs. This study addresses these indirect consequences of massive introduction of green energy sources on reservoir operations. Short-term reservoir operation, under different wind penetration scenarios, is simulated using a replica of Chile's ISO's scheduling optimization tools. Furthermore, an ongoing study is exploring the potential to augment the capacity the existing hydro-power plants to better cope with the balancing needs due to a higher wind power share in the system. As reservoir releases determine to a great extent flows at downstream locations, hourly time series of turbined flows for 24-hour periods were computed for selected combinations between new wind farms and increased capacity of existing hydropower plants. These time series are compiled into subdaily hydrologic alteration (SDHA) indexes (Zimmerman et al, 2010). The resulting sample of indexes is then analyzed using duration curves. Results show a clear increase in the SDHA for every reservoir of the system as more fluctuating renewables are integrated into the system. High

  6. DRAGON Grid: A Three-Dimensional Hybrid Grid Generation Code Developed

    NASA Technical Reports Server (NTRS)

    Liou, Meng-Sing

    2000-01-01

    Because grid generation can consume 70 percent of the total analysis time for a typical three-dimensional viscous flow simulation for a practical engineering device, payoffs from research and development could reduce costs and increase throughputs considerably. In this study, researchers at the NASA Glenn Research Center at Lewis Field developed a new hybrid grid approach with the advantages of flexibility, high-quality grids suitable for an accurate resolution of viscous regions, and a low memory requirement. These advantages will, in turn, reduce analysis time and increase accuracy. They result from an innovative combination of structured and unstructured grids to represent the geometry and the computation domain. The present approach makes use of the respective strengths of both the structured and unstructured grid methods, while minimizing their weaknesses. First, the Chimera grid generates high-quality, mostly orthogonal meshes around individual components. This process is flexible and can be done easily. Normally, these individual grids are required overlap each other so that the solution on one grid can communicate with another. However, when this communication is carried out via a nonconservative interpolation procedure, a spurious solution can result. Current research is aimed at entirely eliminating this undesired interpolation by directly replacing arbitrary grid overlapping with a nonstructured grid called a DRAGON grid, which uses the same set of conservation laws over the entire region, thus ensuring conservation everywhere. The DRAGON grid is shown for a typical film-cooled turbine vane with 33 holes and 3 plenum compartments. There are structured grids around each geometrical entity and unstructured grids connecting them. In fiscal year 1999, Glenn researchers developed and tested the three-dimensional DRAGON grid-generation tools. A flow solver suitable for the DRAGON grid has been developed, and a series of validation tests are underway.

  7. Guidelines for Implementing Advanced Distribution Management Systems-Requirements for DMS Integration with DERMS and Microgrids

    SciTech Connect

    Wang, Jianhui; Chen, Chen; Lu, Xiaonan

    2015-08-01

    This guideline focuses on the integration of DMS with DERMS and microgrids connected to the distribution grid by defining generic and fundamental design and implementation principles and strategies. It starts by addressing the current status, objectives, and core functionalities of each system, and then discusses the new challenges and the common principles of DMS design and implementation for integration with DERMS and microgrids to realize enhanced grid operation reliability and quality power delivery to consumers while also achieving the maximum energy economics from the DER and microgrid connections.

  8. TASMANIAN Sparse Grids Module

    SciTech Connect

    and Drayton Munster, Miroslav Stoyanov

    2013-09-20

    Sparse Grids are the family of methods of choice for multidimensional integration and interpolation in low to moderate number of dimensions. The method is to select extend a one dimensional set of abscissas, weights and basis functions by taking a subset of all possible tensor products. The module provides the ability to create global and local approximations based on polynomials and wavelets. The software has three components, a library, a wrapper for the library that provides a command line interface via text files ad a MATLAB interface via the command line tool.

  9. TASMANIAN Sparse Grids Module

    2013-09-20

    Sparse Grids are the family of methods of choice for multidimensional integration and interpolation in low to moderate number of dimensions. The method is to select extend a one dimensional set of abscissas, weights and basis functions by taking a subset of all possible tensor products. The module provides the ability to create global and local approximations based on polynomials and wavelets. The software has three components, a library, a wrapper for the library thatmore » provides a command line interface via text files ad a MATLAB interface via the command line tool.« less

  10. AstroGrid-D: Grid technology for astronomical science

    NASA Astrophysics Data System (ADS)

    Enke, Harry; Steinmetz, Matthias; Adorf, Hans-Martin; Beck-Ratzka, Alexander; Breitling, Frank; Brüsemeister, Thomas; Carlson, Arthur; Ensslin, Torsten; Högqvist, Mikael; Nickelt, Iliya; Radke, Thomas; Reinefeld, Alexander; Reiser, Angelika; Scholl, Tobias; Spurzem, Rainer; Steinacker, Jürgen; Voges, Wolfgang; Wambsganß, Joachim; White, Steve

    2011-02-01

    We present status and results of AstroGrid-D, a joint effort of astrophysicists and computer scientists to employ grid technology for scientific applications. AstroGrid-D provides access to a network of distributed machines with a set of commands as well as software interfaces. It allows simple use of computer and storage facilities and to schedule or monitor compute tasks and data management. It is based on the Globus Toolkit middleware (GT4). Chapter 1 describes the context which led to the demand for advanced software solutions in Astrophysics, and we state the goals of the project. We then present characteristic astrophysical applications that have been implemented on AstroGrid-D in chapter 2. We describe simulations of different complexity, compute-intensive calculations running on multiple sites (Section 2.1), and advanced applications for specific scientific purposes (Section 2.2), such as a connection to robotic telescopes (Section 2.2.3). We can show from these examples how grid execution improves e.g. the scientific workflow. Chapter 3 explains the software tools and services that we adapted or newly developed. Section 3.1 is focused on the administrative aspects of the infrastructure, to manage users and monitor activity. Section 3.2 characterises the central components of our architecture: The AstroGrid-D information service to collect and store metadata, a file management system, the data management system, and a job manager for automatic submission of compute tasks. We summarise the successfully established infrastructure in chapter 4, concluding with our future plans to establish AstroGrid-D as a platform of modern e-Astronomy.

  11. The International Symposium on Grids and Clouds

    NASA Astrophysics Data System (ADS)

    The International Symposium on Grids and Clouds (ISGC) 2012 will be held at Academia Sinica in Taipei from 26 February to 2 March 2012, with co-located events and workshops. The conference is hosted by the Academia Sinica Grid Computing Centre (ASGC). 2012 is the decennium anniversary of the ISGC which over the last decade has tracked the convergence, collaboration and innovation of individual researchers across the Asia Pacific region to a coherent community. With the continuous support and dedication from the delegates, ISGC has provided the primary international distributed computing platform where distinguished researchers and collaboration partners from around the world share their knowledge and experiences. The last decade has seen the wide-scale emergence of e-Infrastructure as a critical asset for the modern e-Scientist. The emergence of large-scale research infrastructures and instruments that has produced a torrent of electronic data is forcing a generational change in the scientific process and the mechanisms used to analyse the resulting data deluge. No longer can the processing of these vast amounts of data and production of relevant scientific results be undertaken by a single scientist. Virtual Research Communities that span organisations around the world, through an integrated digital infrastructure that connects the trust and administrative domains of multiple resource providers, have become critical in supporting these analyses. Topics covered in ISGC 2012 include: High Energy Physics, Biomedicine & Life Sciences, Earth Science, Environmental Changes and Natural Disaster Mitigation, Humanities & Social Sciences, Operations & Management, Middleware & Interoperability, Security and Networking, Infrastructure Clouds & Virtualisation, Business Models & Sustainability, Data Management, Distributed Volunteer & Desktop Grid Computing, High Throughput Computing, and High Performance, Manycore & GPU Computing.

  12. Smart Grid Communications System Blueprint

    NASA Astrophysics Data System (ADS)

    Clark, Adrian; Pavlovski, Chris

    2010-10-01

    Telecommunications operators are well versed in deploying 2G and 3G wireless networks. These networks presently support the mobile business user and/or retail consumer wishing to place conventional voice calls and data connections. The electrical power industry has recently commenced transformation of its distribution networks by deploying smart monitoring and control devices throughout their networks. This evolution of the network into a `smart grid' has also motivated the need to deploy wireless technologies that bridge the communication gap between the smart devices and information technology systems. The requirements of these networks differ from traditional wireless networks that communications operators have deployed, which have thus far forced energy companies to consider deploying their own wireless networks. We present our experience in deploying wireless networks to support the smart grid and highlight the key properties of these networks. These characteristics include application awareness, support for large numbers of simultaneous cell connections, high service coverage and prioritized routing of data. We also outline our target blueprint architecture that may be useful to the industry in building wireless and fixed networks to support the smart grid. By observing our experiences, telecommunications operators and equipment manufacturers will be able to augment their current networks and products in a way that accommodates the needs of the emerging industry of smart grids and intelligent electrical networks.

  13. Connecting Node

    NASA Technical Reports Server (NTRS)

    Johnson, Christopher J.; Raboin, Jasen L.; Spexarth, Gary R.

    2009-01-01

    A paper describes the Octanode, a connecting node that facilitates the integration of multiple docking mechanisms, hatches, windows, and internal and external systems with the use of flat surfaces. The Octanode is a 26- faced Great Rhombicuboctahedron Archi medean solid with six octagonshaped panels, eight hexagon-shaped panels, and 12 square panels using three unique, simple, flat shapes to construct a spherical approximation. Each flat shape can be constructed with a variety of material and manufacturing techniques, such as honeycomb composite panels or a pocketed skinstringer configuration, using conventional means. The flat shapes can be connected together and sealed to create a pressurizable volume by the use of any conventional means including welding or fastening devices and sealant. The node can then be connected to other elements to allow transfer between those elements, or it could serve as an airlock. The Octanode can be manufactured on the ground and can be integrated with subsystems including hatches and ports. The node can then be transported to its intended location, whether on orbit or on surface. Any of the flat panels could be replaced by curved ones, turning the node into a copula. Windows may be placed on flat panes with optimal viewing angles that are not blocked by large connecting nodes. The advantage of using flat panels to represent a spherical approximation is that this allows for easier integration of subsystems and design features.

  14. The Network Modification (NeMo) Tool: Elucidating the Effect of White Matter Integrity Changes on Cortical and Subcortical Structural Connectivity

    PubMed Central

    Maruta, Jun; Relkin, Norman; Raj, Ashish

    2013-01-01

    Abstract Accurate prediction of brain dysfunction caused by disease or injury requires the quantification of resultant neural connectivity changes compared with the normal state. There are many methods with which to assess anatomical changes in structural or diffusion magnetic resonance imaging, but most overlook the topology of white matter (WM) connections that make up the healthy brain network. Here, a new neuroimaging software pipeline called the Network Modification (NeMo) Tool is presented that associates alterations in WM integrity with expected changes in neural connectivity between gray matter regions. The NeMo Tool uses a large reference set of healthy tractograms to assess implied network changes arising from a particular pattern of WM alteration on a region- and network-wise level. In this way, WM integrity changes can be extrapolated to the cortices and deep brain nuclei, enabling assessment of functional and cognitive alterations. Unlike current techniques that assess network dysfunction, the NeMo tool does not require tractography in pathological brains for which the algorithms may be unreliable or diffusion data are unavailable. The versatility of the NeMo Tool is demonstrated by applying it to data from patients with Alzheimer's disease, fronto-temporal dementia, normal pressure hydrocephalus, and mild traumatic brain injury. This tool fills a gap in the quantitative neuroimaging field by enabling an investigation of morphological and functional implications of changes in structural WM integrity. PMID:23855491

  15. Data Grid Management Systems

    NASA Technical Reports Server (NTRS)

    Moore, Reagan W.; Jagatheesan, Arun; Rajasekar, Arcot; Wan, Michael; Schroeder, Wayne

    2004-01-01

    The "Grid" is an emerging infrastructure for coordinating access across autonomous organizations to distributed, heterogeneous computation and data resources. Data grids are being built around the world as the next generation data handling systems for sharing, publishing, and preserving data residing on storage systems located in multiple administrative domains. A data grid provides logical namespaces for users, digital entities and storage resources to create persistent identifiers for controlling access, enabling discovery, and managing wide area latencies. This paper introduces data grids and describes data grid use cases. The relevance of data grids to digital libraries and persistent archives is demonstrated, and research issues in data grids and grid dataflow management systems are discussed.

  16. Connecting science and the musical arts in teaching tone quality: Integrating Helmholtz motion and master violin teachers' pedagogies

    NASA Astrophysics Data System (ADS)

    Collins, Cheri D.

    Is it possible for students to achieve better tone quality from even their factory-made violins? All violins, regardless of cost, have a common capacity for good tone in certain frequencies. These signature modes outline the first position range of a violin (196-600 hertz). To activate this basic capacity of all violins, the string must fully vibrate. To accomplish this the bow must be pulled across the string with enough pressure (relative to its speed and contact point) for the horsehairs to catch. This friction permits the string to vibrate in Helmholtz Motion, which produces a corner that travels along the edge of the string between the bridge and the nut. Creating this corner is the most fundamental technique for achieving good tone. The findings of celebrated scientists Ernest Chladni, Hermann von Helmholtz, and John Schelleng will be discussed and the tone-production pedagogy of master teachers Carl Flesch, Ivan Galamian, Robert Gerle, and Simon Fischer will be investigated. Important connections between the insights of these scientists and master teachers are evident. Integrating science and art can provide teachers with a better understanding of the characteristics of good tone. This can help their students achieve the best possible sound from their instruments. In the private studio the master teacher may not use the words "Helmholtz Motion." Yet through modeling and listening students are able to understand and create a quality tone. Music teachers without experience in string performance may be assigned to teach strings in classroom and ensembles settings. As a result modeling good tone is not always possible. However, all teachers and conductors can understand the fundamental behavior of string vibration and adapt their instruction strategies towards student success. Better tonal quality for any string instrument is ultimately achieved. Mastery and use of the Helmholtz Motion benefits teachers and students alike. Simple practice exercises for teaching

  17. The CrossGrid project

    NASA Astrophysics Data System (ADS)

    Kunze, M.; CrossGrid Collaboration

    2003-04-01

    There are many large-scale problems that require new approaches to computing, such as earth observation, environmental management, biomedicine, industrial and scientific modeling. The CrossGrid project addresses realistic problems in medicine, environmental protection, flood prediction, and physics analysis and is oriented towards specific end-users: Medical doctors, who could obtain new tools to help them to obtain correct diagnoses and to guide them during operations; industries, that could be advised on the best timing for some critical operations involving risk of pollution; flood crisis teams, that could predict the risk of a flood on the basis of historical records and actual hydrological and meteorological data; physicists, who could optimize the analysis of massive volumes of data distributed across countries and continents. Corresponding applications will be based on Grid technology and could be complex and difficult to use: the CrossGrid project aims at developing several tools that will make the Grid more friendly for average users. Portals for specific applications will be designed, that should allow for easy connection to the Grid, create a customized work environment, and provide users with all necessary information to get their job done.

  18. The Overgrid Interface for Computational Simulations on Overset Grids

    NASA Technical Reports Server (NTRS)

    Chan, William M.; Kwak, Dochan (Technical Monitor)

    2002-01-01

    Computational simulations using overset grids typically involve multiple steps and a variety of software modules. A graphical interface called OVERGRID has been specially designed for such purposes. Data required and created by the different steps include geometry, grids, domain connectivity information and flow solver input parameters. The interface provides a unified environment for the visualization, processing, generation and diagnosis of such data. General modules are available for the manipulation of structured grids and unstructured surface triangulations. Modules more specific for the overset approach include surface curve generators, hyperbolic and algebraic surface grid generators, a hyperbolic volume grid generator, Cartesian box grid generators, and domain connectivity: pre-processing tools. An interface provides automatic selection and viewing of flow solver boundary conditions, and various other flow solver inputs. For problems involving multiple components in relative motion, a module is available to build the component/grid relationships and to prescribe and animate the dynamics of the different components.

  19. Connecting Body and Mind: A Resource Guide to Integrated Health Care in Texas and the United States

    ERIC Educational Resources Information Center

    Lopez, Molly; Coleman-Beattie, Brenda; Jahnke, Lauren; Sanchez, Katherine

    2008-01-01

    There is a call across the country and in Texas to improve health care systems through integrated care. Integrated health care is the systematic coordination of physical and behavioral health services. The idea is that physical and behavioral health problems often occur at the same time and that integrating services will provide the best results…

  20. The Functional Segregation and Integration Model: Mixture Model Representations of Consistent and Variable Group-Level Connectivity in fMRI.

    PubMed

    Churchill, Nathan W; Madsen, Kristoffer; Mørup, Morten

    2016-10-01

    The brain consists of specialized cortical regions that exchange information between each other, reflecting a combination of segregated (local) and integrated (distributed) processes that define brain function. Functional magnetic resonance imaging (fMRI) is widely used to characterize these functional relationships, although it is an ongoing challenge to develop robust, interpretable models for high-dimensional fMRI data. Gaussian mixture models (GMMs) are a powerful tool for parcellating the brain, based on the similarity of voxel time series. However, conventional GMMs have limited parametric flexibility: they only estimate segregated structure and do not model interregional functional connectivity, nor do they account for network variability across voxels or between subjects. To address these issues, this letter develops the functional segregation and integration model (FSIM). This extension of the GMM framework simultaneously estimates spatial clustering and the most consistent group functional connectivity structure. It also explicitly models network variability, based on voxel- and subject-specific network scaling profiles. We compared the FSIM to standard GMM in a predictive cross-validation framework and examined the importance of different model parameters, using both simulated and experimental resting-state data. The reliability of parcellations is not significantly altered by flexibility of the FSIM, whereas voxel- and subject-specific network scaling profiles significantly improve the ability to predict functional connectivity in independent test data. Moreover, the FSIM provides a set of interpretable parameters to characterize both consistent and variable aspects functional connectivity structure. As an example of its utility, we use subject-specific network profiles to identify brain regions where network expression predicts subject age in the experimental data. Thus, the FSIM is effective at summarizing functional connectivity structure in group

  1. The Functional Segregation and Integration Model: Mixture Model Representations of Consistent and Variable Group-Level Connectivity in fMRI.

    PubMed

    Churchill, Nathan W; Madsen, Kristoffer; Mørup, Morten

    2016-10-01

    The brain consists of specialized cortical regions that exchange information between each other, reflecting a combination of segregated (local) and integrated (distributed) processes that define brain function. Functional magnetic resonance imaging (fMRI) is widely used to characterize these functional relationships, although it is an ongoing challenge to develop robust, interpretable models for high-dimensional fMRI data. Gaussian mixture models (GMMs) are a powerful tool for parcellating the brain, based on the similarity of voxel time series. However, conventional GMMs have limited parametric flexibility: they only estimate segregated structure and do not model interregional functional connectivity, nor do they account for network variability across voxels or between subjects. To address these issues, this letter develops the functional segregation and integration model (FSIM). This extension of the GMM framework simultaneously estimates spatial clustering and the most consistent group functional connectivity structure. It also explicitly models network variability, based on voxel- and subject-specific network scaling profiles. We compared the FSIM to standard GMM in a predictive cross-validation framework and examined the importance of different model parameters, using both simulated and experimental resting-state data. The reliability of parcellations is not significantly altered by flexibility of the FSIM, whereas voxel- and subject-specific network scaling profiles significantly improve the ability to predict functional connectivity in independent test data. Moreover, the FSIM provides a set of interpretable parameters to characterize both consistent and variable aspects functional connectivity structure. As an example of its utility, we use subject-specific network profiles to identify brain regions where network expression predicts subject age in the experimental data. Thus, the FSIM is effective at summarizing functional connectivity structure in group

  2. Integrated Analysis and Visualization of Group Differences in Structural and Functional Brain Connectivity: Applications in Typical Ageing and Schizophrenia.

    PubMed

    Langen, Carolyn D; White, Tonya; Ikram, M Arfan; Vernooij, Meike W; Niessen, Wiro J

    2015-01-01

    Structural and functional brain connectivity are increasingly used to identify and analyze group differences in studies of brain disease. This study presents methods to analyze uni- and bi-modal brain connectivity and evaluate their ability to identify differences. Novel visualizations of significantly different connections comparing multiple metrics are presented. On the global level, "bi-modal comparison plots" show the distribution of uni- and bi-modal group differences and the relationship between structure and function. Differences between brain lobes are visualized using "worm plots". Group differences in connections are examined with an existing visualization, the "connectogram". These visualizations were evaluated in two proof-of-concept studies: (1) middle-aged versus elderly subjects; and (2) patients with schizophrenia versus controls. Each included two measures derived from diffusion weighted images and two from functional magnetic resonance images. The structural measures were minimum cost path between two anatomical regions according to the "Statistical Analysis of Minimum cost path based Structural Connectivity" method and the average fractional anisotropy along the fiber. The functional measures were Pearson's correlation and partial correlation of mean regional time series. The relationship between structure and function was similar in both studies. Uni-modal group differences varied greatly between connectivity types. Group differences were identified in both studies globally, within brain lobes and between regions. In the aging study, minimum cost path was highly effective in identifying group differences on all levels; fractional anisotropy and mean correlation showed smaller differences on the brain lobe and regional levels. In the schizophrenia study, minimum cost path and fractional anisotropy showed differences on the global level and within brain lobes; mean correlation showed small differences on the lobe level. Only fractional anisotropy

  3. Integrated Analysis and Visualization of Group Differences in Structural and Functional Brain Connectivity: Applications in Typical Ageing and Schizophrenia.

    PubMed

    Langen, Carolyn D; White, Tonya; Ikram, M Arfan; Vernooij, Meike W; Niessen, Wiro J

    2015-01-01

    Structural and functional brain connectivity are increasingly used to identify and analyze group differences in studies of brain disease. This study presents methods to analyze uni- and bi-modal brain connectivity and evaluate their ability to identify differences. Novel visualizations of significantly different connections comparing multiple metrics are presented. On the global level, "bi-modal comparison plots" show the distribution of uni- and bi-modal group differences and the relationship between structure and function. Differences between brain lobes are visualized using "worm plots". Group differences in connections are examined with an existing visualization, the "connectogram". These visualizations were evaluated in two proof-of-concept studies: (1) middle-aged versus elderly subjects; and (2) patients with schizophrenia versus controls. Each included two measures derived from diffusion weighted images and two from functional magnetic resonance images. The structural measures were minimum cost path between two anatomical regions according to the "Statistical Analysis of Minimum cost path based Structural Connectivity" method and the average fractional anisotropy along the fiber. The functional measures were Pearson's correlation and partial correlation of mean regional time series. The relationship between structure and function was similar in both studies. Uni-modal group differences varied greatly between connectivity types. Group differences were identified in both studies globally, within brain lobes and between regions. In the aging study, minimum cost path was highly effective in identifying group differences on all levels; fractional anisotropy and mean correlation showed smaller differences on the brain lobe and regional levels. In the schizophrenia study, minimum cost path and fractional anisotropy showed differences on the global level and within brain lobes; mean correlation showed small differences on the lobe level. Only fractional anisotropy

  4. GENI: Grid Hardware and Software

    SciTech Connect

    2012-01-09

    GENI Project: The 15 projects in ARPA-E’s GENI program, short for “Green Electricity Network Integration,” aim to modernize the way electricity is transmitted in the U.S. through advances in hardware and software for the electric grid. These advances will improve the efficiency and reliability of electricity transmission, increase the amount of renewable energy the grid can utilize, and provide energy suppliers and consumers with greater control over their power flows in order to better manage peak power demand and cost.

  5. Resting-State Brain and the FTO Obesity Risk Allele: Default Mode, Sensorimotor, and Salience Network Connectivity Underlying Different Somatosensory Integration and Reward Processing between Genotypes.

    PubMed

    Olivo, Gaia; Wiemerslage, Lyle; Nilsson, Emil K; Solstrand Dahlberg, Linda; Larsen, Anna L; Olaya Búcaro, Marcela; Gustafsson, Veronica P; Titova, Olga E; Bandstein, Marcus; Larsson, Elna-Marie; Benedict, Christian; Brooks, Samantha J; Schiöth, Helgi B

    2016-01-01

    Single-nucleotide polymorphisms (SNPs) of the fat mass and obesity associated (FTO) gene are linked to obesity, but how these SNPs influence resting-state neural activation is unknown. Few brain-imaging studies have investigated the influence of obesity-related SNPs on neural activity, and no study has investigated resting-state connectivity patterns. We tested connectivity within three, main resting-state networks: default mode (DMN), sensorimotor (SMN), and salience network (SN) in 30 male participants, grouped based on genotype for the rs9939609 FTO SNP, as well as punishment and reward sensitivity measured by the Behavioral Inhibition (BIS) and Behavioral Activation System (BAS) questionnaires. Because obesity is associated with anomalies in both systems, we calculated a BIS/BAS ratio (BBr) accounting for features of both scores. A prominence of BIS over BAS (higher BBr) resulted in increased connectivity in frontal and paralimbic regions. These alterations were more evident in the obesity-associated AA genotype, where a high BBr was also associated with increased SN connectivity in dopaminergic circuitries, and in a subnetwork involved in somatosensory integration regarding food. Participants with AA genotype and high BBr, compared to corresponding participants in the TT genotype, also showed greater DMN connectivity in regions involved in the processing of food cues, and in the SMN for regions involved in visceral perception and reward-based learning. These findings suggest that neural connectivity patterns influence the sensitivity toward punishment and reward more closely in the AA carriers, predisposing them to developing obesity. Our work explains a complex interaction between genetics, neural patterns, and behavioral measures in determining the risk for obesity and may help develop individually-tailored strategies for obesity prevention. PMID:26924971

  6. Resting-State Brain and the FTO Obesity Risk Allele: Default Mode, Sensorimotor, and Salience Network Connectivity Underlying Different Somatosensory Integration and Reward Processing between Genotypes

    PubMed Central

    Olivo, Gaia; Wiemerslage, Lyle; Nilsson, Emil K.; Solstrand Dahlberg, Linda; Larsen, Anna L.; Olaya Búcaro, Marcela; Gustafsson, Veronica P.; Titova, Olga E.; Bandstein, Marcus; Larsson, Elna-Marie; Benedict, Christian; Brooks, Samantha J.; Schiöth, Helgi B.

    2016-01-01

    Single-nucleotide polymorphisms (SNPs) of the fat mass and obesity associated (FTO) gene are linked to obesity, but how these SNPs influence resting-state neural activation is unknown. Few brain-imaging studies have investigated the influence of obesity-related SNPs on neural activity, and no study has investigated resting-state connectivity patterns. We tested connectivity within three, main resting-state networks: default mode (DMN), sensorimotor (SMN), and salience network (SN) in 30 male participants, grouped based on genotype for the rs9939609 FTO SNP, as well as punishment and reward sensitivity measured by the Behavioral Inhibition (BIS) and Behavioral Activation System (BAS) questionnaires. Because obesity is associated with anomalies in both systems, we calculated a BIS/BAS ratio (BBr) accounting for features of both scores. A prominence of BIS over BAS (higher BBr) resulted in increased connectivity in frontal and paralimbic regions. These alterations were more evident in the obesity-associated AA genotype, where a high BBr was also associated with increased SN connectivity in dopaminergic circuitries, and in a subnetwork involved in somatosensory integration regarding food. Participants with AA genotype and high BBr, compared to corresponding participants in the TT genotype, also showed greater DMN connectivity in regions involved in the processing of food cues, and in the SMN for regions involved in visceral perception and reward-based learning. These findings suggest that neural connectivity patterns influence the sensitivity toward punishment and reward more closely in the AA carriers, predisposing them to developing obesity. Our work explains a complex interaction between genetics, neural patterns, and behavioral measures in determining the risk for obesity and may help develop individually-tailored strategies for obesity prevention. PMID:26924971

  7. Globus MEDICUS - federation of DICOM medical imaging devices into healthcare Grids.

    PubMed

    Erberich, Stephan G; Silverstein, Jonathan C; Chervenak, Ann; Schuler, Robert; Nelson, Marvin D; Kesselman, Carl

    2007-01-01

    The Digital Imaging and Communications in Medicine (DICOM) standard defines Radiology medical device interoperability and image data exchange between modalities, image databases - Picture Archiving and Communication Systems (PACS) - and image review end-points. However the scope of DICOM and PACS technology is currently limited to the trusted and static environment of the hospital. In order to meet the demand for ad-hoc tele-radiology and image guided medical procedures within the global healthcare enterprise, a new technology must provide mobility, security, flexible scale of operations, and rapid responsiveness for DICOM medical devices and subsequently medical image data. Grid technology, an informatics approach to securely federate independently operated computing, storage, and data management resources at the global scale over public networks, meets these core requirements. Here we present an approach to federate DICOM and PACS devices for large-scale medical image workflows within a global healthcare enterprise. The Globus MEDICUS (Medical Imaging and Computing for Unified Information Sharing) project uses the standards-based Globus Toolkit Grid infrastructure to vertically integrate a new service for DICOM devices - the DICOM Grid Interface Service (DGIS). This new service translates between DICOM and Grid operations and thus transparently extends DICOM to Globus based Grid infrastructure. This Grid image workflow paradigm has been designed to provide not only solutions for global image communication, but fault-tolerance and disaster recovery using Grid data replication technology. Actual use-case of 40 MEDICUS Grid connected international hospitals of the Childerns Oncology Group and the Neuroblastoma Cancer Foundation and further clinical applications are discussed. The open-source Globus MEDICU http://dev.globus.org/wiki/Incubator/MEDICUS. PMID:17476069

  8. Spatial services grid

    NASA Astrophysics Data System (ADS)

    Cao, Jian; Li, Qi; Cheng, Jicheng

    2005-10-01

    This paper discusses the concept, key technologies and main application of Spatial Services Grid. The technologies of Grid computing and Webservice is playing a revolutionary role in studying the spatial information services. The concept of the SSG (Spatial Services Grid) is put forward based on the SIG (Spatial Information Grid) and OGSA (open grid service architecture). Firstly, the grid computing is reviewed and the key technologies of SIG and their main applications are reviewed. Secondly, the grid computing and three kinds of SIG (in broad sense)--SDG (spatial data grid), SIG (spatial information grid) and SSG (spatial services grid) and their relationships are proposed. Thirdly, the key technologies of the SSG (spatial services grid) is put forward. Finally, three representative applications of SSG (spatial services grid) are discussed. The first application is urban location based services gird, which is a typical spatial services grid and can be constructed on OGSA (Open Grid Services Architecture) and digital city platform. The second application is region sustainable development grid which is the key to the urban development. The third application is Region disaster and emergency management services grid.

  9. Final report for %22High performance computing for advanced national electric power grid modeling and integration of solar generation resources%22, LDRD Project No. 149016.

    SciTech Connect

    Reno, Matthew J.; Riehm, Andrew Charles; Hoekstra, Robert John; Munoz-Ramirez, Karina; Stamp, Jason Edwin; Phillips, Laurence R.; Adams, Brian M.; Russo, Thomas V.; Oldfield, Ron A.; McLendon, William Clarence, III; Nelson, Jeffrey Scott; Hansen, Clifford W.; Richardson, Bryan T.; Stein, Joshua S.; Schoenwald, David Alan; Wolfenbarger, Paul R.

    2011-02-01

    Design and operation of the electric power grid (EPG) relies heavily on computational models. High-fidelity, full-order models are used to study transient phenomena on only a small part of the network. Reduced-order dynamic and power flow models are used when analysis involving thousands of nodes are required due to the computational demands when simulating large numbers of nodes. The level of complexity of the future EPG will dramatically increase due to large-scale deployment of variable renewable generation, active load and distributed generation resources, adaptive protection and control systems, and price-responsive demand. High-fidelity modeling of this future grid will require significant advances in coupled, multi-scale tools and their use on high performance computing (HPC) platforms. This LDRD report demonstrates SNL's capability to apply HPC resources to these 3 tasks: (1) High-fidelity, large-scale modeling of power system dynamics; (2) Statistical assessment of grid security via Monte-Carlo simulations of cyber attacks; and (3) Development of models to predict variability of solar resources at locations where little or no ground-based measurements are available.

  10. Integrating configuration workflows with project management system

    NASA Astrophysics Data System (ADS)

    Nilsen, Dimitri; Weber, Pavel

    2014-06-01

    The complexity of the heterogeneous computing resources, services and recurring infrastructure changes at the GridKa WLCG Tier-1 computing center require a structured approach to configuration management and optimization of interplay between functional components of the whole system. A set of tools deployed at GridKa, including Puppet, Redmine, Foreman, SVN and Icinga, provides the administrative environment giving the possibility to define and develop configuration workflows, reduce the administrative effort and improve sustainable operation of the whole computing center. In this presentation we discuss the developed configuration scenarios implemented at GridKa, which we use for host installation, service deployment, change management procedures, service retirement etc. The integration of Puppet with a project management tool like Redmine provides us with the opportunity to track problem issues, organize tasks and automate these workflows. The interaction between Puppet and Redmine results in automatic updates of the issues related to the executed workflow performed by different system components. The extensive configuration workflows require collaboration and interaction between different departments like network, security, production etc. at GridKa. Redmine plugins developed at GridKa and integrated in its administrative environment provide an effective way of collaboration within the GridKa team. We present the structural overview of the software components, their connections, communication protocols and show a few working examples of the workflows and their automation.

  11. Integrated Analysis and Visualization of Group Differences in Structural and Functional Brain Connectivity: Applications in Typical Ageing and Schizophrenia

    PubMed Central

    Langen, Carolyn D.; Ikram, M. Arfan; Vernooij, Meike W.

    2015-01-01

    Structural and functional brain connectivity are increasingly used to identify and analyze group differences in studies of brain disease. This study presents methods to analyze uni- and bi-modal brain connectivity and evaluate their ability to identify differences. Novel visualizations of significantly different connections comparing multiple metrics are presented. On the global level, “bi-modal comparison plots” show the distribution of uni- and bi-modal group differences and the relationship between structure and function. Differences between brain lobes are visualized using “worm plots”. Group differences in connections are examined with an existing visualization, the “connectogram”. These visualizations were evaluated in two proof-of-concept studies: (1) middle-aged versus elderly subjects; and (2) patients with schizophrenia versus controls. Each included two measures derived from diffusion weighted images and two from functional magnetic resonance images. The structural measures were minimum cost path between two anatomical regions according to the “Statistical Analysis of Minimum cost path based Structural Connectivity” method and the average fractional anisotropy along the fiber. The functional measures were Pearson’s correlation and partial correlation of mean regional time series. The relationship between structure and function was similar in both studies. Uni-modal group differences varied greatly between connectivity types. Group differences were identified in both studies globally, within brain lobes and between regions. In the aging study, minimum cost path was highly effective in identifying group differences on all levels; fractional anisotropy and mean correlation showed smaller differences on the brain lobe and regional levels. In the schizophrenia study, minimum cost path and fractional anisotropy showed differences on the global level and within brain lobes; mean correlation showed small differences on the lobe level. Only

  12. Northwestern University schizophrenia data sharing for SchizConnect: A longitudinal dataset for large-scale integration.

    PubMed

    Kogan, Alex; Alpert, Kathryn; Ambite, Jose Luis; Marcus, Daniel S; Wang, Lei

    2016-01-01

    In this paper, we describe an instance of the Northwestern University Schizophrenia Data and Software Tool (NUSDAST), a schizophrenia-related dataset hosted at XNAT Central, and the SchizConnect data portal used for accessing and sharing the dataset. NUSDAST was built and extended upon existing, standard schemas available for data sharing on XNAT Central (http://central.xnat.org/). With the creation of SchizConnect, we were able to link NUSDAST to other neuroimaging data sources and create a powerful, federated neuroimaging resource.

  13. A Bidirectional High-Power-Quality Grid Interface With a Novel Bidirectional Noninverted Buck Boost Converter for PHEVs

    SciTech Connect

    Onar, Omer C

    2012-01-01

    Plug-in hybrid electric vehicles (PHEVs) will play a vital role in future sustainable transportation systems due to their potential in terms of energy security, decreased environmental impact, improved fuel economy, and better performance. Moreover, new regulations have been established to improve the collective gas mileage, cut greenhouse gas emissions, and reduce dependence on foreign oil. This paper primarily focuses on two major thrust areas of PHEVs. First, it introduces a grid-friendly bidirectional alternating current/direct current ac/dc dc/ac rectifier/inverter for facilitating vehicle-to-grid (V2G) integration of PHEVs. Second, it presents an integrated bidirectional noninverted buck boost converter that interfaces the energy storage device of the PHEV to the dc link in both grid-connected and driving modes. The proposed bidirectional converter has minimal grid-level disruptions in terms of power factor and total harmonic distortion, with less switching noise. The integrated bidirectional dc/dc converter assists the grid interface converter to track the charge/discharge power of the PHEV battery. In addition, while driving, the dc/dc converter provides a regulated dc link voltage to the motor drive and captures the braking energy during regenerative braking.

  14. An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras

    SciTech Connect

    Bolotnikov, A. E. Ackley, K.; Camarda, G. S.; Cherches, C.; Cui, Y.; De Geronimo, G.; Fried, J.; Hossain, A.; Mahler, G.; Maritato, M.; Roy, U.; Salwen, C.; Vernon, E.; Yang, G.; James, R. B.; Hodges, D.; Lee, W.; Petryk, M.

    2015-07-15

    We developed a robust and low-cost array of virtual Frisch-grid CdZnTe detectors coupled to a front-end readout application-specific integrated circuit (ASIC) for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6 × 6 × 15 mm{sup 3} detectors grouped into 3 × 3 sub-arrays of 2 × 2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readout electronics. The further enhancement of the arrays’ performance and reduction of their cost are possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.

  15. An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras.

    PubMed

    Bolotnikov, A E; Ackley, K; Camarda, G S; Cherches, C; Cui, Y; De Geronimo, G; Fried, J; Hodges, D; Hossain, A; Lee, W; Mahler, G; Maritato, M; Petryk, M; Roy, U; Salwen, C; Vernon, E; Yang, G; James, R B

    2015-07-01

    We developed a robust and low-cost array of virtual Frisch-grid CdZnTe detectors coupled to a front-end readout application-specific integrated circuit (ASIC) for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6 × 6 × 15 mm(3) detectors grouped into 3 × 3 sub-arrays of 2 × 2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readout electronics. The further enhancement of the arrays' performance and reduction of their cost are possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.

  16. Intelligent geospatial data retrieval based on the geospatial grid portal

    NASA Astrophysics Data System (ADS)

    Yuan, Jie; Yue, Peng; Gong, Jianya

    2008-12-01

    The Open Geospatial Consortium (OGC) standard-compliant services define a set of standard interfaces for geospatial Web services to achieve the interoperability in an open distributed computing environment. Grid technology is a distributed computing infrastructure to allow distributed resources sharing and coordinated problem solving. Based on the OGC standards for geospatial services and grid technology, we propose the geospatial grid portal to integrate and interoperate grid-enabled geospatial services. The implementation of the geospatial grid portal is based on a three-tier architecture which consists of grid-enabled geospatial services tier, grid service portal tier and application tier. The OGC standard-compliant services are deployed in a grid environment, the so-called grid-enabled geospatial services. Grid service portals for each type of geospatial services, including WFS, WMS, WCS and CSW, provide a single point of Web entry to discover and access different types of geospatial information. A resource optimization mechanism is incorporated into these service portals to optimize the selection of grid nodes. At the top tier, i.e. the application tier, the client interacts with a semantic middleware for the grid CSW portal, thus allows the semantics-enabled search. The proposed approach can not only optimize the grid resource selection among multiple grid nodes, but also incorporate the power of Semantic Web technology into geospatial grid portal to allow the precise discovery of geospatial data.

  17. Smart Grid Risk Management

    NASA Astrophysics Data System (ADS)

    Abad Lopez, Carlos Adrian

    Current electricity infrastructure is being stressed from several directions -- high demand, unreliable supply, extreme weather conditions, accidents, among others. Infrastructure planners have, traditionally, focused on only the cost of the system; today, resilience and sustainability are increasingly becoming more important. In this dissertation, we develop computational tools for efficiently managing electricity resources to help create a more reliable and sustainable electrical grid. The tools we present in this work will help electric utilities coordinate demand to allow the smooth and large scale integration of renewable sources of energy into traditional grids, as well as provide infrastructure planners and operators in developing countries a framework for making informed planning and control decisions in the presence of uncertainty. Demand-side management is considered as the most viable solution for maintaining grid stability as generation from intermittent renewable sources increases. Demand-side management, particularly demand response (DR) programs that attempt to alter the energy consumption of customers either by using price-based incentives or up-front power interruption contracts, is more cost-effective and sustainable in addressing short-term supply-demand imbalances when compared with the alternative that involves increasing fossil fuel-based fast spinning reserves. An essential step in compensating participating customers and benchmarking the effectiveness of DR programs is to be able to independently detect the load reduction from observed meter data. Electric utilities implementing automated DR programs through direct load control switches are also interested in detecting the reduction in demand to efficiently pinpoint non-functioning devices to reduce maintenance costs. We develop sparse optimization methods for detecting a small change in the demand for electricity of a customer in response to a price change or signal from the utility

  18. "It's All Connected!" Nursing Students' Experiences of a New Form of Case Seminar Integrating Medical and Nursing Science

    ERIC Educational Resources Information Center

    Turunen Olsson, Pernilla; Weurlander, Maria; Mattiasson, Anne-Cathrine; Wärn Hede, Gunnel; Panagiotidis, Georgios; Broberger, Eva; Hult, Håkan; Wernerson, Annika

    2016-01-01

    Traditionally, nursing students learn medical subjects and nursing separately, which makes it difficult to develop an integrated understanding. This study aimed to explore nursing students' experiences of participating in a case seminar integrating medical and nursing sciences and if, and how, it contributed to their learning. A case seminar…

  19. Parallel grid population

    SciTech Connect

    Wald, Ingo; Ize, Santiago

    2015-07-28

    Parallel population of a grid with a plurality of objects using a plurality of processors. One example embodiment is a method for parallel population of a grid with a plurality of objects using a plurality of processors. The method includes a first act of dividing a grid into n distinct grid portions, where n is the number of processors available for populating the grid. The method also includes acts of dividing a plurality of objects into n distinct sets of objects, assigning a distinct set of objects to each processor such that each processor determines by which distinct grid portion(s) each object in its distinct set of objects is at least partially bounded, and assigning a distinct grid portion to each processor such that each processor populates its distinct grid portion with any objects that were previously determined to be at least partially bounded by its distinct grid portion.

  20. Décrypthon grid - grid resources dedicated to neuromuscular disorders.

    PubMed

    Bard, N; Bolze, R; Caron, E; Desprez, F; Heymann, M; Friedrich, A; Moulinier, L; Nguyen, N H; Poch, O; Toursel, T

    2010-01-01

    Thanks to the availability of computational grids and their middleware, a seamless access to computation and storage resources is provided to application developers and scientists. The Décrypthon project is one example of such a high performance platform. In this paper, we present the architecture of the platform, the middleware developed to facilitate access to several servers deployed in France, and the data center for integrating large biological datasets over multiple sites, supported by a new query language and integration of various tools. The SM2PH project represents an example of a biological application that exploits the capacities of the Décrypthon grid. The goal of SM2PH is a better understanding of mutations involved in human monogenic diseases, their impact on the 3D structure of the protein and the subsequent consequences for the pathological phenotypes. PMID:20543432

  1. Scientific Grid computing.

    PubMed

    Coveney, Peter V

    2005-08-15

    We introduce a definition of Grid computing which is adhered to throughout this Theme Issue. We compare the evolution of the World Wide Web with current aspirations for Grid computing and indicate areas that need further research and development before a generally usable Grid infrastructure becomes available. We discuss work that has been done in order to make scientific Grid computing a viable proposition, including the building of Grids, middleware developments, computational steering and visualization. We review science that has been enabled by contemporary computational Grids, and associated progress made through the widening availability of high performance computing.

  2. Mesoscale Climate Evaluation Using Grid Computing

    NASA Astrophysics Data System (ADS)

    Campos Velho, H. F.; Freitas, S. R.; Souto, R. P.; Charao, A. S.; Ferraz, S.; Roberti, D. R.; Streck, N.; Navaux, P. O.; Maillard, N.; Collischonn, W.; Diniz, G.; Radin, B.

    2012-04-01

    The CLIMARS project is focused to establish an operational environment for seasonal climate prediction for the Rio Grande do Sul state, Brazil. The dynamical downscaling will be performed with the use of several software platforms and hardware infrastructure to carry out the investigation on mesoscale of the global change impact. The grid computing takes advantage of geographically spread out computer systems, connected by the internet, for enhancing the power of computation. The ensemble climate prediction is an appropriated application for processing on grid computing, because the integration of each ensemble member does not have a dependency on information from another ensemble members. The grid processing is employed to compute the 20-year climatology and the long range simulations under ensemble methodology. BRAMS (Brazilian Regional Atmospheric Model) is a mesoscale model developed from a version of the RAMS (from the Colorado State University - CSU, USA). BRAMS model is the tool for carrying out the dynamical downscaling from the IPCC scenarios. Long range BRAMS simulations will provide data for some climate (data) analysis, and supply data for numerical integration of different models: (a) Regime of the extreme events for temperature and precipitation fields: statistical analysis will be applied on the BRAMS data, (b) CCATT-BRAMS (Coupled Chemistry Aerosol Tracer Transport - BRAMS) is an environmental prediction system that will be used to evaluate if the new standards of temperature, rain regime, and wind field have a significant impact on the pollutant dispersion in the analyzed regions, (c) MGB-IPH (Portuguese acronym for the Large Basin Model (MGB), developed by the Hydraulic Research Institute, (IPH) from the Federal University of Rio Grande do Sul (UFRGS), Brazil) will be employed to simulate the alteration of the river flux under new climate patterns. Important meteorological input variables for the MGB-IPH are the precipitation (most relevant

  3. The PlaNet Consortium: A Network of European Plant Databases Connecting Plant Genome Data in an Integrated Biological Knowledge Resource

    PubMed Central

    Ernst, R.; Mayer, K. F. X.

    2004-01-01

    The completion of the Arabidopsis genome and the large collections of other plant sequences generated in recent years have sparked extensive functional genomics efforts. However, the utilization of this data is inefficient, as data sources are distributed and heterogeneous and efforts at data integration are lagging behind. PlaNet aims to overcome the limitations of individual efforts as well as the limitations of heterogeneous, independent data collections. PlaNet is a distributed effort among European bioinformatics groups and plant molecular biologists to establish a comprehensive integrated database in a collaborative network. Objectives are the implementation of infrastructure and data sources to capture plant genomic information into a comprehensive, integrated platform. This will facilitate the systematic exploration of Arabidopsis and other plants. New methods for data exchange, database integration and access are being developed to create a highly integrated, federated data resource for research. The connection between the individual resources is realized with BioMOBY. BioMOBY provides an architecture for the discovery and distribution of biological data through web services. While knowledge is centralized, data is maintained at its primary source without a need for warehousing. To standardize nomenclature and data representation, ontologies and generic data models are defined in interaction with the relevant communities.Minimal data models should make it simple to allow broad integration, while inheritance allows detail and depth to be added to more complex data objects without losing integration. To allow expert annotation and keep databases curated, local and remote annotation interfaces are provided. Easy and direct access to all data is key to the project. PMID:18629059

  4. Bridging Science and Public Understanding of Long-term Soil, Water, and Vegetation Monitoring: Opportunities for broader impact connections with InTeGrate

    NASA Astrophysics Data System (ADS)

    Bruckner, M. Z.; Orr, C. H.; Manduca, C. A.

    2015-12-01

    Long-term monitoring of soils, water, and vegetation is crucial in understanding sustainability-related issues faced by society in our changing environment. Promoting buy in through public literacy and preparing the future workforce to address these challenges is a key goal of the InTeGrate project. The InTeGrate project is an NSF STEP Center that endeavors to infuse teaching about the Earth into undergraduate courses across the curriculum. The project aims to connect this knowledge to societal issues that students can relate to and opens the door to interdisciplinary problem-solving that is needed to face the Grand Challenges facing society. The project features publicly-available interdisciplinary, faculty-contributed teaching materials that engage students in learning about the Earth by focusing on pressing topics. These topics include water, food resources, energy, and hazards. Further, web pages built around teaching methods such as service learning, working with data, and teaching in the field, help engage students in active learning and making meaningful connections to their coursework. In addition, teams of interdisciplinary faculty are creating project-developed courses and modules designed to engage and promote students' literacy in sustainability and global change issues. These materials are designed for both science and non-science majors at the undergraduate level and have been rigorously reviewed and tested in the classroom. Topics include sustainable agriculture, soil and society, climate change, critical zone science, water resources, and more. We invite you to partner with the InTeGrate project as you think about broader impacts related to your work. Examples include contributing to the community collections by creating a case study detailing your project and how faculty can use it in their classroom, designing example activities that utilize your datasets, and more. Check out the site at: serc.carleton.edu/integrate/

  5. Grid-based Visualization Framework

    NASA Astrophysics Data System (ADS)

    Thiebaux, M.; Tangmunarunkit, H.; Kesselman, C.

    2003-12-01

    Advances in science and engineering have put high demands on tools for high-performance large-scale visual data exploration and analysis. For example, earthquake scientists can now study earthquake phenomena from first principle physics-based simulations. These simulations can generate large amounts of data, possibly high spatial resolution, and long time series. Single-system visualization software running on commodity machines cannot scale up to the large amounts of data generated by these simulations. To address this problem, we propose a flexible and extensible Grid-based visualization framework for time-critical, interactively controlled visual browsing of spatially and temporally large datasets in a Grid environment. Our framework leverages Grid resources for scalable computation and data storage to maintain performance and interactivity with large visualization jobs. Our framework utilizes Globus Toolkit 2.4 components for security (i.e., GSI), resource allocation and management (i.e., DUROC, GRAM) and communication (i.e., Globus-IO) to couple commodity desktops with remote, scalable storage and computational resources in a Grid for interactive data exploration. There are two major components in this framework---Grid Data Transport (GDT) and the Grid Visualization Utility (GVU). GDT provides libraries for performing parallel data filtering and parallel data exchange among Grid resources. GDT allows arbitrary data filtering to be integrated into the system. It also facilitates multi-tiered pipeline topology construction of compute resources and displays. In addition to scientific visualization applications, GDT can be used to support other applications that require parallel processing and parallel transfer of partial ordered independent files, such as file-set transfer. On top of GDT, we have developed the Grid Visualization Utility (GVU), which is designed to assist visualization dataset management, including file formatting, data transport and automatic

  6. Parallel algorithms for dynamically partitioning unstructured grids

    SciTech Connect

    Diniz, P.; Plimpton, S.; Hendrickson, B.; Leland, R.

    1994-10-01

    Grid partitioning is the method of choice for decomposing a wide variety of computational problems into naturally parallel pieces. In problems where computational load on the grid or the grid itself changes as the simulation progresses, the ability to repartition dynamically and in parallel is attractive for achieving higher performance. We describe three algorithms suitable for parallel dynamic load-balancing which attempt to partition unstructured grids so that computational load is balanced and communication is minimized. The execution time of algorithms and the quality of the partitions they generate are compared to results from serial partitioners for two large grids. The integration of the algorithms into a parallel particle simulation is also briefly discussed.

  7. An Extensible Information Grid for Risk Management

    NASA Technical Reports Server (NTRS)

    Maluf, David A.; Bell, David G.

    2003-01-01

    This paper describes recent work on developing an extensible information grid for risk management at NASA - a RISK INFORMATION GRID. This grid is being developed by integrating information grid technology with risk management processes for a variety of risk related applications. To date, RISK GRID applications are being developed for three main NASA processes: risk management - a closed-loop iterative process for explicit risk management, program/project management - a proactive process that includes risk management, and mishap management - a feedback loop for learning from historical risks that escaped other processes. This is enabled through an architecture involving an extensible database, structuring information with XML, schemaless mapping of XML, and secure server-mediated communication using standard protocols.

  8. PNNL Future Power Grid Initiative-developed GridOPTICS Software System (GOSS)

    SciTech Connect

    2014-11-03

    The power grid is changing and evolving. One aspect of this change is the growing use of smart meters and other devices, which are producing large volumes of useful data. However, in many cases, the data can’t be translated quickly into actionable guidance to improve grid performance. There's a need for innovative tools. The GridOPTICS(TM) Software System, or GOSS, developed through PNNL's Future Power Grid Initiative, is open source and became publicly available in spring 2014. The value of this middleware is that it easily integrates grid applications with sources of data and facilitates communication between them. Such a capability provides a foundation for developing a range of applications to improve grid management.

  9. Method of grid generation

    DOEpatents

    Barnette, Daniel W.

    2002-01-01

    The present invention provides a method of grid generation that uses the geometry of the problem space and the governing relations to generate a grid. The method can generate a grid with minimized discretization errors, and with minimal user interaction. The method of the present invention comprises assigning grid cell locations so that, when the governing relations are discretized using the grid, at least some of the discretization errors are substantially zero. Conventional grid generation is driven by the problem space geometry; grid generation according to the present invention is driven by problem space geometry and by governing relations. The present invention accordingly can provide two significant benefits: more efficient and accurate modeling since discretization errors are minimized, and reduced cost grid generation since less human interaction is required.

  10. Dynamic Power Grid Simulation

    2015-09-14

    GridDyn is a part of power grid simulation toolkit. The code is designed using modern object oriented C++ methods utilizing C++11 and recent Boost libraries to ensure compatibility with multiple operating systems and environments.

  11. An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras

    DOE PAGES

    Bolotnikov, A. E.; Ackley, K.; Camarda, G. S.; Cherches, C.; Cui, Y.; De Geronimo, G.; Fried, J.; Hodges, D.; Hossain, A.; Lee, W.; et al

    2015-07-28

    We developed a robust and low-cost array of virtual Frisch-grid CdZnTe (CZT) detectors coupled to a front-end readout ASIC for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6x6x15 mm3 detectors grouped into 3x3 sub-arrays of 2x2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readout electronics.more » The further enhancement of the arrays’ performance and reduction of their cost are made possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.« less

  12. An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras

    SciTech Connect

    Bolotnikov, A. E.; Ackley, K.; Camarda, G. S.; Cherches, C.; Cui, Y.; De Geronimo, G.; Fried, J.; Hodges, D.; Hossain, A.; Lee, W.; Mahler, G.; Maritato, M.; Petryk, M.; Roy, U.; Salwen, C.; Vernon, E.; Yang, G.; James, R. B.

    2015-07-28

    We developed a robust and low-cost array of virtual Frisch-grid CdZnTe (CZT) detectors coupled to a front-end readout ASIC for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6x6x15 mm3 detectors grouped into 3x3 sub-arrays of 2x2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readout electronics. The further enhancement of the arrays’ performance and reduction of their cost are made possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.

  13. A roadmap for caGrid, an enterprise Grid architecture for biomedical research.

    PubMed

    Saltz, Joel; Hastings, Shannon; Langella, Stephen; Oster, Scott; Kurc, Tahsin; Payne, Philip; Ferreira, Renato; Plale, Beth; Goble, Carole; Ervin, David; Sharma, Ashish; Pan, Tony; Permar, Justin; Brezany, Peter; Siebenlist, Frank; Madduri, Ravi; Foster, Ian; Shanbhag, Krishnakant; Mead, Charlie; Chue Hong, Neil

    2008-01-01

    caGrid is a middleware system which combines the Grid computing, the service oriented architecture, and the model driven architecture paradigms to support development of interoperable data and analytical resources and federation of such resources in a Grid environment. The functionality provided by caGrid is an essential and integral component of the cancer Biomedical Informatics Grid (caBIG) program. This program is established by the National Cancer Institute as a nationwide effort to develop enabling informatics technologies for collaborative, multi-institutional biomedical research with the overarching goal of accelerating translational cancer research. Although the main application domain for caGrid is cancer research, the infrastructure provides a generic framework that can be employed in other biomedical research and healthcare domains. The development of caGrid is an ongoing effort, adding new functionality and improvements based on feedback and use cases from the community. This paper provides an overview of potential future architecture and tooling directions and areas of improvement for caGrid and caGrid-like systems. This summary is based on discussions at a roadmap workshop held in February with participants from biomedical research, Grid computing, and high performance computing communities. PMID:18560123

  14. Bus.py: A GridLAB-D Communication Interface for Smart Distribution Grid Simulations

    SciTech Connect

    Hansen, Timothy M.; Palmintier, Bryan; Suryanarayanan, Siddharth; Maciejewski, Anthony A.; Siegel, Howard Jay

    2015-07-03

    As more Smart Grid technologies (e.g., distributed photovoltaic, spatially distributed electric vehicle charging) are integrated into distribution grids, static distribution simulations are no longer sufficient for performing modeling and analysis. GridLAB-D is an agent-based distribution system simulation environment that allows fine-grained end-user models, including geospatial and network topology detail. A problem exists in that, without outside intervention, once the GridLAB-D simulation begins execution, it will run to completion without allowing the real-time interaction of Smart Grid controls, such as home energy management systems and aggregator control. We address this lack of runtime interaction by designing a flexible communication interface, Bus.py (pronounced bus-dot-pie), that uses Python to pass messages between one or more GridLAB-D instances and a Smart Grid simulator. This work describes the design and implementation of Bus.py, discusses its usefulness in terms of some Smart Grid scenarios, and provides an example of an aggregator-based residential demand response system interacting with GridLAB-D through Bus.py. The small scale example demonstrates the validity of the interface and shows that an aggregator using said interface is able to control residential loads in GridLAB-D during runtime to cause a reduction in the peak load on the distribution system in (a) peak reduction and (b) time-of-use pricing cases.

  15. IPG Power Grid Overview

    NASA Technical Reports Server (NTRS)

    Hinke, Thomas

    2003-01-01

    This presentation will describe what is meant by grids and then cover the current state of the IPG. This will include an overview of the middleware that is key to the operation of the grid. The presentation will then describe some of the future directions that are planned for the IPG. Finally the presentation will conclude with a brief overview of the Global Grid Forum, which is a key activity that will contribute to the successful availability of grid components.

  16. GridLAB-D: An Agent-Based Simulation Framework for Smart Grids

    SciTech Connect

    Chassin, David P.; Fuller, Jason C.; Djilali, Ned

    2014-06-23

    Simulation of smart grid technologies requires a fundamentally new approach to integrated modeling of power systems, energy markets, building technologies, and the plethora of other resources and assets that are becoming part of modern electricity production, delivery, and consumption systems. As a result, the US Department of Energy’s Office of Electricity commissioned the development of a new type of power system simulation tool called GridLAB-D that uses an agent-based approach to simulating smart grids. This paper presents the numerical methods and approach to time-series simulation used by GridLAB-D and reviews applications in power system studies, market design, building control system design, and integration of wind power in a smart grid.

  17. GridLAB-D: An Agent-Based Simulation Framework for Smart Grids

    DOE PAGES

    Chassin, David P.; Fuller, Jason C.; Djilali, Ned

    2014-01-01

    Simulation of smart grid technologies requires a fundamentally new approach to integrated modeling of power systems, energy markets, building technologies, and the plethora of other resources and assets that are becoming part of modern electricity production, delivery, and consumption systems. As a result, the US Department of Energy’s Office of Electricity commissioned the development of a new type of power system simulation tool called GridLAB-D that uses an agent-based approach to simulating smart grids. This paper presents the numerical methods and approach to time-series simulation used by GridLAB-D and reviews applications in power system studies, market design, building control systemmore » design, and integration of wind power in a smart grid.« less

  18. Skeletonization of Gridded Potential-Field Images

    NASA Astrophysics Data System (ADS)

    Gao, L.; Morozov, I. B.

    2012-12-01

    A new approach to skeletonization was developed for gridded potential-field data. Generally, skeletonization is a pattern-recognition technique allowing automatic recognition of near-linear features in the images, measurement of their parameters, and analyzing them for similarities. Our approach decomposes the images into arbitrarily-oriented "wavelets" characterized by positive or negative amplitudes, orientation angles, spatial dimensions, polarities, and other attributes. Orientations of the wavelets are obtained by scanning the azimuths to detect the strike direction of each anomaly. The wavelets are connected according to the similarities of these attributes, which leads to a "skeleton" map of the potential-field data. In addition, 2-D filtering is conducted concurrently with the wavelet-identification process, which allows extracting parameters of background trends and reduces the adverse effects of low-frequency background (which is often strong in potential-field maps) on skeletonization.. By correlating the neighboring wavelets, linear anomalies are identified and characterized. The advantages of this algorithm are the generality and isotropy of feature detection, as well as being specifically designed for gridded data. With several options for background-trend extraction, the stability for identification of lineaments is improved and optimized. The algorithm is also integrated in a powerful processing system which allows combining it with numerous other tools, such as filtering, computation of analytical signal, empirical mode decomposition, and various types of plotting. The method is applied to potential-field data for the Western Canada Sedimentary Basin, in a study area which extends from southern Saskatchewan into southwestern Manitoba. The target is the structure of crystalline basement beneath Phanerozoic sediments. The examples illustrate that skeletonization aid in the interpretation of complex structures at different scale lengths. The results

  19. Integrated pest management is the lucrative bridge connecting the ever emerging knowledge islands of genetics and ecology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Integrated pest management has long been considered a profit- and product (or technology)-driven multidisciplinary research field that maximizes crop yield and minimizes pest-inflicted economic losses. The introduction of transgenic crops has revolutionized crop protection and pest management by com...

  20. Chimera Grid Tools

    NASA Technical Reports Server (NTRS)

    Chan, William M.; Rogers, Stuart E.; Nash, Steven M.; Buning, Pieter G.; Meakin, Robert

    2005-01-01

    Chimera Grid Tools (CGT) is a software package for performing computational fluid dynamics (CFD) analysis utilizing the Chimera-overset-grid method. For modeling flows with viscosity about geometrically complex bodies in relative motion, the Chimera-overset-grid method is among the most computationally cost-effective methods for obtaining accurate aerodynamic results. CGT contains a large collection of tools for generating overset grids, preparing inputs for computer programs that solve equations of flow on the grids, and post-processing of flow-solution data. The tools in CGT include grid editing tools, surface-grid-generation tools, volume-grid-generation tools, utility scripts, configuration scripts, and tools for post-processing (including generation of animated images of flows and calculating forces and moments exerted on affected bodies). One of the tools, denoted OVERGRID, is a graphical user interface (GUI) that serves to visualize the grids and flow solutions and provides central access to many other tools. The GUI facilitates the generation of grids for a new flow-field configuration. Scripts that follow the grid generation process can then be constructed to mostly automate grid generation for similar configurations. CGT is designed for use in conjunction with a computer-aided-design program that provides the geometry description of the bodies, and a flow-solver program.

  1. Techniques for grid manipulation and adaptation. [computational fluid dynamics

    NASA Technical Reports Server (NTRS)

    Choo, Yung K.; Eisemann, Peter R.; Lee, Ki D.

    1992-01-01

    Two approaches have been taken to provide systematic grid manipulation for improved grid quality. One is the control point form (CPF) of algebraic grid generation. It provides explicit control of the physical grid shape and grid spacing through the movement of the control points. It works well in the interactive computer graphics environment and hence can be a good candidate for integration with other emerging technologies. The other approach is grid adaptation using a numerical mapping between the physical space and a parametric space. Grid adaptation is achieved by modifying the mapping functions through the effects of grid control sources. The adaptation process can be repeated in a cyclic manner if satisfactory results are not achieved after a single application.

  2. Development of the Finite Difference Time Domain Method on a Lebedev Grid for Anisotropic Materials

    NASA Astrophysics Data System (ADS)

    Nauta, Marcel D.

    The finite-difference time-domain (FDTD) method is derived on a Lebedev grid, instead of the standard Yee grid, to better represent the constitutive relations in anisotropic materials. The Lebedev grid extends the Yee grid by approximating Maxwell's equations with tensor constitutive relations using only central differences. A dispersion relation with stability criteria is derived and it is proven that the Lebedev grid has a consistent calculus. An integral derivation of the update equations illustrates how to appropriately excite the grid. This approach is also used to derive the update equations at planar material interfaces and domain edge PEC. Lebedev grid results are compared with analytical and Yee grid solutions using an equal memory comparison. Numerical results show that the Lebedev grid suffers greater dispersion error but better represents material interfaces. Focus is given to generalizing the concepts that make the Yee grid robust for isotropic materials. Keywords: FDTD, anisotropic materials, Lebedev grid, collocated grids.

  3. Interoperable PKI Data Distribution in Computational Grids

    SciTech Connect

    Pala, Massimiliano; Cholia, Shreyas; Rea, Scott A.; Smith, Sean W.

    2008-07-25

    One of the most successful working examples of virtual organizations, computational grids need authentication mechanisms that inter-operate across domain boundaries. Public Key Infrastructures(PKIs) provide sufficient flexibility to allow resource managers to securely grant access to their systems in such distributed environments. However, as PKIs grow and services are added to enhance both security and usability, users and applications must struggle to discover available resources-particularly when the Certification Authority (CA) is alien to the relying party. This article presents how to overcome these limitations of the current grid authentication model by integrating the PKI Resource Query Protocol (PRQP) into the Grid Security Infrastructure (GSI).

  4. Cloud feedback studies with a physics grid

    SciTech Connect

    Dipankar, Anurag; Stevens, Bjorn

    2013-02-07

    During this project the investigators implemented a fully parallel version of dual-grid approach in main frame code ICON, implemented a fully conservative first-order interpolation scheme for horizontal remapping, integrated UCLA-LES micro-scale model into ICON to run parallely in selected columns, and did cloud feedback studies on aqua-planet setup to evaluate the classical parameterization on a small domain. The micro-scale model may be run in parallel with the classical parameterization, or it may be run on a "physics grid" independent of the dynamics grid.

  5. Computer Program For Generation Of Surface Grids

    NASA Technical Reports Server (NTRS)

    Ching, Raymond; Pierce, Lawrence

    1993-01-01

    S3D is useful computer program for generation of grids on surfaces of bodies having complicated shapes. Product of integration of robust and widely applicable interpolation technique with latest in computer-workstation technology. Incorporates highly efficient and easy-to-use graphical-interface software, enables real-time and interactive analyses of surface-geometry data and facilitates construction of surface grids.

  6. A perspective on unstructured grid flow solvers

    NASA Technical Reports Server (NTRS)

    Venkatakrishnan, V.

    1995-01-01

    This survey paper assesses the status of compressible Euler and Navier-Stokes solvers on unstructured grids. Different spatial and temporal discretization options for steady and unsteady flows are discussed. The integration of these components into an overall framework to solve practical problems is addressed. Issues such as grid adaptation, higher order methods, hybrid discretizations and parallel computing are briefly discussed. Finally, some outstanding issues and future research directions are presented.

  7. FermiGrid

    SciTech Connect

    Yocum, D.R.; Berman, E.; Canal, P.; Chadwick, K.; Hesselroth, T.; Garzoglio, G.; Levshina, T.; Sergeev, V.; Sfiligoi, I.; Sharma, N.; Timm, S.; /Fermilab

    2007-05-01

    As one of the founding members of the Open Science Grid Consortium (OSG), Fermilab enables coherent access to its production resources through the Grid infrastructure system called FermiGrid. This system successfully provides for centrally managed grid services, opportunistic resource access, development of OSG Interfaces for Fermilab, and an interface to the Fermilab dCache system. FermiGrid supports virtual organizations (VOs) including high energy physics experiments (USCMS, MINOS, D0, CDF, ILC), astrophysics experiments (SDSS, Auger, DES), biology experiments (GADU, Nanohub) and educational activities.

  8. Grid Architecture 2

    SciTech Connect

    Taft, Jeffrey D.

    2016-01-01

    The report describes work done on Grid Architecture under the auspices of the Department of Electricity Office of Electricity Delivery and Reliability in 2015. As described in the first Grid Architecture report, the primary purpose of this work is to provide stakeholder insight about grid issues so as to enable superior decision making on their part. Doing this requires the creation of various work products, including oft-times complex diagrams, analyses, and explanations. This report provides architectural insights into several important grid topics and also describes work done to advance the science of Grid Architecture as well.

  9. On Accuracy of Adaptive Grid Methods for Captured Shocks

    NASA Technical Reports Server (NTRS)

    Yamaleev, Nail K.; Carpenter, Mark H.

    2002-01-01

    The accuracy of two grid adaptation strategies, grid redistribution and local grid refinement, is examined by solving the 2-D Euler equations for the supersonic steady flow around a cylinder. Second- and fourth-order linear finite difference shock-capturing schemes, based on the Lax-Friedrichs flux splitting, are used to discretize the governing equations. The grid refinement study shows that for the second-order scheme, neither grid adaptation strategy improves the numerical solution accuracy compared to that calculated on a uniform grid with the same number of grid points. For the fourth-order scheme, the dominant first-order error component is reduced by the grid adaptation, while the design-order error component drastically increases because of the grid nonuniformity. As a result, both grid adaptation techniques improve the numerical solution accuracy only on the coarsest mesh or on very fine grids that are seldom found in practical applications because of the computational cost involved. Similar error behavior has been obtained for the pressure integral across the shock. A simple analysis shows that both grid adaptation strategies are not without penalties in the numerical solution accuracy. Based on these results, a new grid adaptation criterion for captured shocks is proposed.

  10. Parallel Grid Manipulations in Earth Science Calculations

    NASA Technical Reports Server (NTRS)

    Sawyer, W.; Lucchesi, R.; daSilva, A.; Takacs, L. L.

    1999-01-01

    The National Aeronautics and Space Administration (NASA) Data Assimilation Office (DAO) at the Goddard Space Flight Center is moving its data assimilation system to massively parallel computing platforms. This parallel implementation of GEOS DAS will be used in the DAO's normal activities, which include reanalysis of data, and operational support for flight missions. Key components of GEOS DAS, including the gridpoint-based general circulation model and a data analysis system, are currently being parallelized. The parallelization of GEOS DAS is also one of the HPCC Grand Challenge Projects. The GEOS-DAS software employs several distinct grids. Some examples are: an observation grid- an unstructured grid of points at which observed or measured physical quantities from instruments or satellites are associated- a highly-structured latitude-longitude grid of points spanning the earth at given latitude-longitude coordinates at which prognostic quantities are determined, and a computational lat-lon grid in which the pole has been moved to a different location to avoid computational instabilities. Each of these grids has a different structure and number of constituent points. In spite of that, there are numerous interactions between the grids, e.g., values on one grid must be interpolated to another, or, in other cases, grids need to be redistributed on the underlying parallel platform. The DAO has designed a parallel integrated library for grid manipulations (PILGRIM) to support the needed grid interactions with maximum efficiency. It offers a flexible interface to generate new grids, define transformations between grids and apply them. Basic communication is currently MPI, however the interfaces defined here could conceivably be implemented with other message-passing libraries, e.g., Cray SHMEM, or with shared-memory constructs. The library is written in Fortran 90. First performance results indicate that even difficult problems, such as above-mentioned pole rotation- a

  11. Senior Research Connects Students with a Living Laboratory As Part of an Integrated Crop and Livestock System

    NASA Astrophysics Data System (ADS)

    Senturklu, Songul; Landblom, Douglas; Brevik, Eric C.

    2015-04-01

    Soil, water, soil microbes, and solar energy are the main sources that sustain life on this planet. Without them working in concert, neither plants nor animals would survive. Considering the efficiency of animal production targets, soil must be protected and improved. Therefore, through our sustainable integrated crop and livestock research, we are studying animal and soil interactions from the soil to the plate. Integrating beef cattle systems into a diverse cropping system is providing a living laboratory for education beyond the traditional classroom setting. To establish the living learning laboratory at the Dickinson Research Extension Center, a five-crop rotation was established that included adapted cool and warm season grasses and broadleaf crops. The crop rotation is: sunflower > hard red spring wheat > fall seeded winter triticale-hairy vetch (hay)/spring seeded 7-species cover crop > Corn (85-95 day varieties) > field pea-barley intercrop. Sunflower and spring wheat are harvested for cash crop income in the rotation. Livestock integration occurs when yearling steers that had previously grazed perennial pastures until mid-August graze field pea-barley and subsequently unharvested corn. Average grazing days for field pea-barley and unharvested corn is 30 and 70 days, respectively. At the end of the grazing period, the yearling steers average 499-544 kg and are moved to a feedlot and fed an additional 75 days until slaughter. Maximizing grazing days and extending the grazing season through integration with the cropping system reduces custom feeding costs and enhances animal profit. Beef cows do not require high quality feed after their calves have been weaned. Therefore, gestating beef cows are an ideal animal to graze cover crops and crop aftermath (residue) after yearling steer grazing and farming operations have been completed. Extending the grazing season for beef cows by grazing cover crops and residues reduces winter feed cost, which is one of the

  12. Senior Research Connects Students with a Living Laboratory As Part of an Integrated Crop and Livestock System

    NASA Astrophysics Data System (ADS)

    Senturklu, Songul; Landblom, Douglas; Brevik, Eric C.

    2015-04-01

    Soil, water, soil microbes, and solar energy are the main sources that sustain life on this planet. Without them working in concert, neither plants nor animals would survive. Considering the efficiency of animal production targets, soil must be protected and improved. Therefore, through our sustainable integrated crop and livestock research, we are studying animal and soil interactions from the soil to the plate. Integrating beef cattle systems into a diverse cropping system is providing a living laboratory for education beyond the traditional classroom setting. To establish the living learning laboratory at the Dickinson Research Extension Center, a five-crop rotation was established that included adapted cool and warm season grasses and broadleaf crops. The crop rotation is: sunflower > hard red spring wheat > fall seeded winter triticale-hairy vetch (hay)/spring seeded 7-species cover crop > Corn (85-95 day varieties) > field pea-barley intercrop. Sunflower and spring wheat are harvested for cash crop income in the rotation. Livestock integration occurs when yearling steers that had previously grazed perennial pastures until mid-August graze field pea-barley and subsequently unharvested corn. Average grazing days for field pea-barley and unharvested corn is 30 and 70 days, respectively. At the end of the grazing period, the yearling steers average 499-544 kg and are moved to a feedlot and fed an additional 75 days until slaughter. Maximizing grazing days and extending the grazing season through integration with the cropping system reduces custom feeding costs and enhances animal profit. Beef cows do not require high quality feed after their calves have been weaned. Therefore, gestating beef cows are an ideal animal to graze cover crops and crop aftermath (residue) after yearling steer grazing and farming operations have been completed. Extending the grazing season for beef cows by grazing cover crops and residues reduces winter feed cost, which is one of the

  13. Integration of porosity, connectivity and permeability measurements to determine syn-eruptive degassing processes during a sub-plinian basaltic eruption

    NASA Astrophysics Data System (ADS)

    Jordan, Simone; Gurioli, Lucia; Colombier, Matthieu; Le Pennec, Jean-Luc; Roche, Olivier

    2015-04-01

    Degassing of the volatile phases is considered to have a major control on the eruption dynamics, particularly in controlling shifts between explosive and extrusive eruption styles. The sub-plinian eruption of the basaltic monogenetic La Vache and Lassolas cone complex in the Chaîne des Puys, France, about 8600 years ago, was an unusual large event that raises the question of the processes that controlled the explosivity of non-differentiated magma and the evolution of this sub-plinian event. This study combines the results of density, porosity, connectivity and permeability measurements of juvenile clasts to determine the state of vesiculation and the presence of open degassing pathways within the melt prior to fragmentation. The volume of connected vesicles is measured using a Helium-Pycnometer, while permeability measurements are conducted using a permeameter recently built at the Laboratoire Magma et Volcans, following Takeuchi et al. (2008). The permeameter has broad measurement ranges of pressure difference (101-105 Pa) and gas-flow rate (10-9-10-5 m3/s). These ranges enable us to measure viscous (Darcian) permeability in the range of 10-17-10-9 m2 for 1 centimetre-scale samples (such as scoria clasts) using the Forchheimer equation (Rust and Cashman, 2004) that accounts for inertial effects caused by non-laminar flow at high gas flow rates. This technique is a relatively new approach to determine the permeability of quenched samples. The integration of porosity and connectivity measurements provides information about the percentage of connected and isolated vesicles, with the connected vesicles forming potential degassing pathways. Our results show that the permeability and the vesicularity of the La Vache and Lassolas pyroclasts correlate very well, defining a trend that is also shown by the permeability data derived from the literature for the Cascades (Saar and Manga, 1999) and the Ambrym volcano (Polacci et al., 2012). The connectivity data of the

  14. Understanding The Smart Grid

    SciTech Connect

    2007-11-15

    The report provides an overview of what the Smart Grid is and what is being done to define and implement it. The electric industry is preparing to undergo a transition from a centralized, producer-controlled network to a decentralized, user-interactive one. Not only will the technology involved in the electric grid change, but the entire business model of the industry will change too. A major objective of the report is to identify the changes that the Smart Grid will bring about so that industry participants can be prepared to face them. A concise overview of the development of the Smart Grid is provided. It presents an understanding of what the Smart Grid is, what new business opportunities or risks might come about due to its introduction, and what activities are already taking place regarding defining or implementing the Smart Grid. This report will be of interest to the utility industry, energy service providers, aggregators, and regulators. It will also be of interest to home/building automation vendors, information technology vendors, academics, consultants, and analysts. The scope of the report includes an overview of the Smart Grid which identifies the main components of the Smart Grid, describes its characteristics, and describes how the Smart Grid differs from the current electric grid. The overview also identifies the key concepts involved in the transition to the Smart Grid and explains why a Smart Grid is needed by identifying the deficiencies of the current grid and the need for new investment. The report also looks at the impact of the Smart Grid, identifying other industries which have gone through a similar transition, identifying the overall benefits of the Smart Grid, and discussing the impact of the Smart Grid on industry participants. Furthermore, the report looks at current activities to implement the Smart Grid including utility projects, industry collaborations, and government initiatives. Finally, the report takes a look at key technology

  15. Navigation in Grid Space with the NAS Grid Benchmarks

    NASA Technical Reports Server (NTRS)

    Frumkin, Michael; Hood, Robert; Biegel, Bryan A. (Technical Monitor)

    2002-01-01

    We present a navigational tool for computational grids. The navigational process is based on measuring the grid characteristics with the NAS Grid Benchmarks (NGB) and using the measurements to assign tasks of a grid application to the grid machines. The tool allows the user to explore the grid space and to navigate the execution at a grid application to minimize its turnaround time. We introduce the notion of gridscape as a user view of the grid and show how it can be me assured by NGB, Then we demonstrate how the gridscape can be used with two different schedulers to navigate a grid application through a rudimentary grid.

  16. Cross-scale interactions, legacies, and spatial connectivity: integrating time and space to predict post-disturbance response across scales

    NASA Astrophysics Data System (ADS)

    Peters, D. P.; Duniway, M.; Browning, D. M.; Yao, J.; Pillsbury, F. C.; Anderson, J.; Havstad, K.

    2011-12-01

    Emergent properties and cross-scale interactions are important in driving landscape-scale dynamics during a disturbance event, such as wildfire. We used these concepts related to changing pattern-process relationships across scales to explain ecological responses following disturbance that resulted in a state change in the Chihuahuan Desert. Our objective was to provide a mechanistic understanding for a large-scale perennial grass recruitment event that was unprecedented over the 100-year history of the Jornada ARS-LTER research site in southern New Mexico. This recruitment event occurred following a sequence of wet years (2004-2008) in an area that experienced gradual shrub invasion (1915-1984) and rapid coppice dune formation (1985-2000) followed by the current stable shrubland state. Long-term observations show that this grass pulse resulted in a significant increase in primary production that could not be explained by historic patterns in rainfall amount alone. In addition, a previous wet sequence of years (1983-1988) did not result in a similar broad-scale recruitment of grasses. We used multiple, long-term datasets and a model of soil water dynamics to test three scale-dependent hypotheses to explain this larger-than-expected production of grasses in the second wet period compared to the first: (1) differences in rainfall seasonality and event size affected a sequence of plant-scale processes, (2) variation in animal abundance affected plant-to-patch scale processes, and (3) differences in soil stability affected patch-scale erosional-depositional processes and spatial connectivity among patches. Our results show that complex interactions between plant- and patch-scale processes and water availability can generate unexpected landscape-scale dynamics following disturbance. A sequence of events influenced by historic legacies and current conditions interact with vegetation-soil feedbacks at plant to patch scales to generate emergent behavior at the landscape

  17. Great Lakes Integrated Sciences + Assessments: Connecting Users and Generators of Scientific Information to Inform Climate Change Adaptation

    NASA Astrophysics Data System (ADS)

    Baule, W. J.; Briley, L.; Brown, D.; Gibbons, E.

    2014-12-01

    The Great Lakes Integrated Sciences + Assessments (GLISA) is one of eleven NOAA Regional Integrated Sciences and Assessments (RISAs) and is a co-hosted by the University of Michigan and Michigan State University. The Great Lakes region falls between areas that are typically defined as the Midwest and Northeast in the United States and also includes portions of Ontario in Canada. This unique and complex region holds approximately 21% of global surface fresh water and is home to 23 million people on the United States side of the basin alone. GLISA functions as a bridge between climate science researchers and boundary organizations in the Great Lakes region, with the goals of contributing to the long-term sustainability of the region in face of a changing climate and to facilitate smart decision-making backed by sound scientific knowledge. Faculty and staff associated with GLISA implement physical and social science practices in daily operations, which includes but is not limited to: activating the boundary chain model to facilitate the transfer of knowledge through the community, integrating local and historical climate data into decision-making processes, addressing uncertainty and the downscaling of climate information, and implementing network analyses to find key access points to information networks across the Great Lakes region. GLISA also provides funding for projects related to climate and climate change adaptation in the Great Lakes region, as well as expertise to partner organizations through collaborations. Information from boundary organizations, stakeholders, and collaborators also flows back to GLISA to aid in the determination of the physical and social science needs of the region. Recent findings point to GLISA playing a crucial role in the scaling information across scales of government and ensuring that federal agencies and local stakeholders are able to learn from one another and share experiences and knowledge to continue building climate ready

  18. Extending the MODPATH algorithm to rectangular unstructured grids

    USGS Publications Warehouse

    Pollock, David W.

    2016-01-01

    The recent release of MODFLOW-USG, which allows model grids to have irregular, unstructured connections, requires a modification of the particle-tracking algorithm used by MODPATH. This paper describes a modification of the semi-analytical particle-tracking algorithm used by MODPATH that allows it to be extended to rectangular-based unstructured grids by dividing grid cells with multi-cell face connections into sub-cells. The new method will be incorporated in the next version of MODPATH which is currently under development.

  19. Extending the MODPATH Algorithm to Rectangular Unstructured Grids.

    PubMed

    Pollock, David W

    2016-01-01

    The recent release of MODFLOW-USG, which allows model grids to have irregular, unstructured connections, requires a modification of the particle-tracking algorithm used by MODPATH. This paper describes a modification of the semi-analytical particle-tracking algorithm used by MODPATH that allows it to be extended to rectangular-based unstructured grids by dividing grid cells with multi-cell face connections into sub-cells. The new method will be incorporated in the next version of MODPATH which is currently under development. PMID:25754305

  20. A numerical algorithm for stress integration of a fiber-fiber kinetics model with Coulomb friction for connective tissue

    NASA Astrophysics Data System (ADS)

    Kojic, M.; Mijailovic, S.; Zdravkovic, N.

    Complex behaviour of connective tissue can be modeled by a fiber-fiber kinetics material model introduced in Mijailovic (1991), Mijailovic et al. (1993). The model is based on the hypothesis of sliding of elastic fibers with Coulomb and viscous friction. The main characteristics of the model were verified experimentally in Mijailovic (1991), and a numerical procedure for one-dimensional tension was developed considering sliding as a contact problem between bodies. In this paper we propose a new and general numerical procedure for calculation of the stress-strain law of the fiber-fiber kinetics model in case of Coulomb friction. Instead of using a contact algorithm (Mijailovic 1991), which is numerically inefficient and never enough reliable, here the history of sliding along the sliding length is traced numerically through a number of segments along the fiber. The algorithm is simple, efficient and reliable and provides solutions for arbitrary cyclic loading, including tension, shear, and tension and shear simultaneously, giving hysteresis loops typical for soft tissue response. The model is built in the finite element technique, providing the possibility of its application to general and real problems. Solved examples illustrate the main characteristics of the model and of the developed numerical method, as well as its applicability to practical problems. Accuracy of some results, for the simple case of uniaxial loading, is verified by comparison with analytical solutions.