GridPix detectors: Production and beam test results

Science.gov (United States)

Koppert, W. J. C.; van Bakel, N.; Bilevych, Y.; Colas, P.; Desch, K.; Fransen, M.; van der Graaf, H.; Hartjes, F.; Hessey, N. P.; Kaminski, J.; Schmitz, J.; Schön, R.; Zappon, F.

2013-12-01

The innovative GridPix detector is a Time Projection Chamber (TPC) that is read out with a Timepix-1 pixel chip. By using wafer post-processing techniques an aluminium grid is placed on top of the chip. When operated, the electric field between the grid and the chip is sufficient to create electron induced avalanches which are detected by the pixels. The time-to-digital converter (TDC) records the drift time enabling the reconstruction of high precision 3D track segments. Recently GridPixes were produced on full wafer scale, to meet the demand for more reliable and cheaper devices in large quantities. In a recent beam test the contribution of both diffusion and time walk to the spatial and angular resolutions of a GridPix detector with a 1.2 mm drift gap are studied in detail. In addition long term tests show that in a significant fraction of the chips the protection layer successfully quenches discharges, preventing harm to the chip.

QBCov: A Linked Data interface for Discrete Global Grid Systems, a new approach to delivering coverage data on the web

Science.gov (United States)

Zhang, Z.; Toyer, S.; Brizhinev, D.; Ledger, M.; Taylor, K.; Purss, M. B. J.

2016-12-01

We are witnessing a rapid proliferation of geoscientific and geospatial data from an increasing variety of sensors and sensor networks. This data presents great opportunities to resolve cross-disciplinary problems. However, working with it often requires an understanding of file formats and protocols seldom used outside of scientific computing, potentially limiting the data's value to other disciplines. In this paper, we present a new approach to serving satellite coverage data on the web, which improves ease-of-access using the principles of linked data. Linked data adapts the concepts and protocols of the human-readable web to machine-readable data; the number of developers familiar with web technologies makes linked data a natural choice for bringing coverages to a wider audience. Our approach to using linked data also makes it possible to efficiently service high-level SPARQL queries: for example, "Retrieve all Landsat ETM+ observations of San Francisco between July and August 2016" can easily be encoded in a single query. We validate the new approach, which we call QBCov, with a reference implementation of the entire stack, including a simple web-based client for interacting with Landsat observations. In addition to demonstrating the utility of linked data for publishing coverages, we investigate the heretofore unexplored relationship between Discrete Global Grid Systems (DGGS) and linked data. Our conclusions are informed by the aforementioned reference implementation of QBCov, which is backed by a hierarchical file format designed around the rHEALPix DGGS. Not only does the choice of a DGGS-based representation provide an efficient mechanism for accessing large coverages at multiple scales, but the ability of DGGS to produce persistent, unique identifiers for spatial regions is especially valuable in a linked data context. This suggests that DGGS has an important role to play in creating sustainable and scalable linked data infrastructures. QBCov is being

Power systems signal processing for smart grids

NARCIS (Netherlands)

Ribeiro, P.F.; Duque, C.A.; Da Silveira, P.M.; Cerqueira, A.S.

2013-01-01

With special relation to smart grids, this book provides clear and comprehensive explanation of how Digital Signal Processing (DSP) and Computational Intelligence (CI) techniques can be applied to solve problems in the power system. Its unique coverage bridges the gap between DSP, electrical power

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

Science.gov (United States)

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.

Photovoltaic Grid-Connected Modeling and Characterization Based on Experimental Results

Science.gov (United States)

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

5 m Gridded multibeam bathymetry of Rota Island, Commonwealth of the Northern Mariana Islands (CNMI)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Rota Island, CNMI. Bottom coverage was achieved in depths between 0 and -1905 meters; this 5-m grid has data only to -400 m. The netCDF and Arc ASCII grids include...

Trends in life science grid: from computing grid to knowledge grid

Directory of Open Access Journals (Sweden)

Konagaya Akihiko

2006-12-01

Full Text Available Abstract Background Grid computing has great potential to become a standard cyberinfrastructure for life sciences which often require high-performance computing and large data handling which exceeds the computing capacity of a single institution. Results This survey reviews the latest grid technologies from the viewpoints of computing grid, data grid and knowledge grid. Computing grid technologies have been matured enough to solve high-throughput real-world life scientific problems. Data grid technologies are strong candidates for realizing "resourceome" for bioinformatics. Knowledge grids should be designed not only from sharing explicit knowledge on computers but also from community formulation for sharing tacit knowledge among a community. Conclusion Extending the concept of grid from computing grid to knowledge grid, it is possible to make use of a grid as not only sharable computing resources, but also as time and place in which people work together, create knowledge, and share knowledge and experiences in a community.

OGC and Grid Interoperability in enviroGRIDS Project

Science.gov (United States)

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

Development of Mitsubishi high thermal performance grid 2 - overview of the development and Dnb test results

International Nuclear Information System (INIS)

Hoshi, M.; Imaizumi, M.; Mori, M.; Hori, K.; Ikeda, K.

2001-01-01

Spacer grid plays fundamental role in thermal performance of PWR fuel assembly. Grid spacer with higher thermal performance gives greater DNB (Departure from Nucleate Boiling) margin for the core. Mitsubishi has developed a prototype Zircaloy grid with higher thermal performance. In this paper, process of the development and DNB test results of the grid is presented. To achieve a goal to design grid with higher DNB performance, CFD (Computational Fluid Dynamics) and Freon DNB test are employed in the development. It is also concerned that the grid should be hydraulically compatible to existing grid. CFD is used in examining mixing capability and pressure drop for early stage of the development. Freon DNB test is used for preliminary checking of DNB performance for several design of the grids. After the final design is fixed, DNB test has been carried out at a high pressure / high temperature water test loop to verify the DNB performance. Also, hydraulic test has been done in a water test loop. The test results show that the grid has higher DNB performance and lower pressure loss coefficient compared with existing grid. It is also concluded that a combination of CFD and Freon DNB testing is successful tool for designing and development of grid. (authors)

Algorithm for Wireless Sensor Networks Based on Grid Management

Directory of Open Access Journals (Sweden)

Geng Zhang

2014-05-01

Full Text Available This paper analyzes the key issues for wireless sensor network trust model and describes a method to build a wireless sensor network, such as the definition of trust for wireless sensor networks, computing and credibility of trust model application. And for the problem that nodes are vulnerable to attack, this paper proposed a grid-based trust algorithm by deep exploration trust model within the framework of credit management. Algorithm for node reliability screening and rotation schedule to cover parallel manner based on the implementation of the nodes within the area covered by trust. And analyze the results of the size of trust threshold has great influence on the safety and quality of coverage throughout the coverage area. The simulation tests the validity and correctness of the algorithm.

Experimental evaluation of square bar and fractal grid-generated turbulent flow inside recirculating water tunnel

Science.gov (United States)

Bornemeier, Matthew; Luznik, Luksa

2017-11-01

High resolution, two dimensional PIV measurements of grid-generated turbulence in the US Naval Academy's recirculating water tunnel (1.8m test section with 0.41m x 0.41m cross sectional area) are presented for two different grid designs. The first grid is a uniform square bar grid with mesh width, M =3.9cm, bar thickness t0 = 1cm, a streamwise thickness of 1cm and resulting solidity of 44%, similar to the conventional grid used by Krogstad and Davidson (2012). The other is Mazellier & Vassilicos' (2010) square fractal grid, SFG17, with fractal iteration count, N =4, thickness ratio tr = 17 and length ratio Lr = 8. Grid patterns differ from the published designs by a circular hole with 4.30cm diameter in the middle that will accept, in future experiments, a shaft connected to an axisymmetric rotating wake generator with diameter, D. Grids were designed to generate turbulence of specific integral length scale of O(D) and intensity of 6% at the prescribed downstream location. Mean tunnel centerline velocity is 2 m/s and measurements are made in a streamwise vertical center plane with nominal individual field of view (FOV) of 12x8 cm2. Spatial coverage in the test section is accomplished by ``tiling'' individual FOV with approximately 2cm overlap. Results will focus on characterizing resulting turbulence in the test section and discussion will include comparison between published results and the present measurements.

GRIZ: Visualization of finite element analysis results on unstructured grids

International Nuclear Information System (INIS)

Dovey, D.; Loomis, M.D.

1994-01-01

GRIZ is a general-purpose post-processing application that supports interactive visualization of finite element analysis results on three-dimensional unstructured grids. GRIZ includes direct-to-videodisc animation capabilities and is being used as a production tool for creating engineering animations

About the Need of Combining Power Market and Power Grid Model Results for Future Energy System Scenarios

Science.gov (United States)

Mende, Denis; Böttger, Diana; Löwer, Lothar; Becker, Holger; Akbulut, Alev; Stock, Sebastian

2018-02-01

The European power grid infrastructure faces various challenges due to the expansion of renewable energy sources (RES). To conduct investigations on interactions between power generation and the power grid, models for the power market as well as for the power grid are necessary. This paper describes the basic functionalities and working principles of both types of models as well as steps to couple power market results and the power grid model. The combination of these models is beneficial in terms of gaining realistic power flow scenarios in the grid model and of being able to pass back results of the power flow and restrictions to the market model. Focus is laid on the power grid model and possible application examples like algorithms in grid analysis, operation and dynamic equipment modelling.

Near-Body Grid Adaption for Overset Grids

Science.gov (United States)

Buning, Pieter G.; Pulliam, Thomas H.

2016-01-01

A solution adaption capability for curvilinear near-body grids has been implemented in the OVERFLOW overset grid computational fluid dynamics code. The approach follows closely that used for the Cartesian off-body grids, but inserts refined grids in the computational space of original near-body grids. Refined curvilinear grids are generated using parametric cubic interpolation, with one-sided biasing based on curvature and stretching ratio of the original grid. Sensor functions, grid marking, and solution interpolation tasks are implemented in the same fashion as for off-body grids. A goal-oriented procedure, based on largest error first, is included for controlling growth rate and maximum size of the adapted grid system. The adaption process is almost entirely parallelized using MPI, resulting in a capability suitable for viscous, moving body simulations. Two- and three-dimensional examples are presented.

Gridded multibeam bathymetry of Howland Island, Pacific Remote Island Areas, Central Pacific

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry at 40m resolution surrounding Howland Island, within the Pacific Remote Island Areas - Central Pacific Ocean. Bottom coverage was achieved in...

Gridded multibeam bathymetry of Baker Island, Pacific Remote Island Areas, Central Pacific

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry at 40m resolution surrounding Baker Island, within the Pacific Remote Island Areas - Central Pacific Ocean. Bottom coverage was achieved in depths...

Grid for Earth Science Applications

Science.gov (United States)

Petitdidier, Monique; Schwichtenberg, Horst

2013-04-01

The civil society at large has addressed to the Earth Science community many strong requirements related in particular to natural and industrial risks, climate changes, new energies. The main critical point is that on one hand the civil society and all public ask for certainties i.e. precise values with small error range as it concerns prediction at short, medium and long term in all domains; on the other hand Science can mainly answer only in terms of probability of occurrence. To improve the answer or/and decrease the uncertainties, (1) new observational networks have been deployed in order to have a better geographical coverage and more accurate measurements have been carried out in key locations and aboard satellites. Following the OECD recommendations on the openness of research and public sector data, more and more data are available for Academic organisation and SMEs; (2) New algorithms and methodologies have been developed to face the huge data processing and assimilation into simulations using new technologies and compute resources. Finally, our total knowledge about the complex Earth system is contained in models and measurements, how we put them together has to be managed cleverly. The technical challenge is to put together databases and computing resources to answer the ES challenges. However all the applications are very intensive computing. Different compute solutions are available and depend on the characteristics of the applications. One of them is Grid especially efficient for independent or embarrassingly parallel jobs related to statistical and parametric studies. Numerous applications in atmospheric chemistry, meteorology, seismology, hydrology, pollution, climate and biodiversity have been deployed successfully on Grid. In order to fulfill requirements of risk management, several prototype applications have been deployed using OGC (Open geospatial Consortium) components with Grid middleware. The Grid has permitted via a huge number of runs to

Complications and results of subdural grid electrode implantation in epilepsy surgery.

Science.gov (United States)

Lee, W S; Lee, J K; Lee, S A; Kang, J K; Ko, T S

2000-11-01

We assessed the risk of delayed subdural hematoma and other complications associated with subdural grid implantation. Forty-nine patients underwent subdural grid implantation with/without subdural strips or depth electrodes from January 1994 to August 1998. To identify the risk associated with subdural grid implantation, a retrospective review of all patients' medical records and radiological studies was performed. The major complications of 50 subdural grid electrode implantations were as follows: four cases (7.8%) of delayed subdural hematoma at the site of the subdural grid, requiring emergency operation; two cases (3.9%) of infection; one case (2.0%) of epidural hematoma; and one case (2.0%) of brain swelling. After subdural hematoma removal, the electrodes were left in place. CCTV monitoring and cortical stimulation studies were continued thereafter. No delayed subdural hematoma has occurred since routine placement of subdural drains was begun. In our experience the worst complication of subdural grid implantation has been delayed subdural hematoma. Placement of subdural drains and close observation may be helpful to prevent this serious complication.

Coverage and Capacity Analysis of Sigfox, LoRa, GPRS, and NB-IoT

DEFF Research Database (Denmark)

Vejlgaard, Benny; Lauridsen, Mads; Nguyen, Huan Cong

2017-01-01

is challenged for indoor coverage. Furthermore, the study analyzes the capacity of the four technologies assuming a traffic growth from 1 to 10 IoT device per user. The conclusion is that the 95 %-tile uplink failure rate for outdoor users is below 5 % for all technologies. For indoor users only NB-IoT provides......In this paper the coverage and capacity of SigFox, LoRa, GPRS, and NB-IoT is compared using a real site deployment covering 8000 km2 in Northern Denmark. Using the existing Telenor cellular site grid it is shown that the four technologies have more than 99 % outdoor coverage, while GPRS...

Smart Grid Communications System Blueprint

Science.gov (United States)

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.

CRED 5m Gridded multibeam bathymetry of Guam Island, Guam U.S. Territory

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry shelf, bank and slope environments of Guam Island, Guam U.S. Territory. Bottom coverage was achieved in depths between 0 and -3532 meters but this...

Gridded multibeam bathymetry of Rota Island, Commonwealth of the Northern Mariana Islands (CNMI)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry shelf, bank and slope environments of Rota Island, CNMI. Bottom coverage was achieved in depths between 0 and -1905 meters. The netCDF and Arc...

New Antarctic Gravity Anomaly Grid for Enhanced Geodetic and Geophysical Studies in Antarctica.

Science.gov (United States)

Scheinert, M; Ferraccioli, F; Schwabe, J; Bell, R; Studinger, M; Damaske, D; Jokat, W; Aleshkova, N; Jordan, T; Leitchenkov, G; Blankenship, D D; Damiani, T M; Young, D; Cochran, J R; Richter, T D

2016-01-28

Gravity surveying is challenging in Antarctica because of its hostile environment and inaccessibility. Nevertheless, many ground-based, airborne and shipborne gravity campaigns have been completed by the geophysical and geodetic communities since the 1980s. We present the first modern Antarctic-wide gravity data compilation derived from 13 million data points covering an area of 10 million km 2 , which corresponds to 73% coverage of the continent. The remove-compute-restore technique was applied for gridding, which facilitated levelling of the different gravity datasets with respect to an Earth Gravity Model derived from satellite data alone. The resulting free-air and Bouguer gravity anomaly grids of 10 km resolution are publicly available. These grids will enable new high-resolution combined Earth Gravity Models to be derived and represent a major step forward towards solving the geodetic polar data gap problem. They provide a new tool to investigate continental-scale lithospheric structure and geological evolution of Antarctica.

New Antarctic Gravity Anomaly Grid for Enhanced Geodetic and Geophysical Studies in Antarctica

Science.gov (United States)

Scheinert, M.; Ferraccioli, F.; Schwabe, J.; Bell, R.; Studinger, M.; Damaske, D.; Jokat, W.; Aleshkova, N.; Jordan, T.; Leitchenkov, G.; Blankenship, D. D.; Damiani, T. M.; Young, D.; Cochran, J. R.; Richter, T. D.

2018-01-01

Gravity surveying is challenging in Antarctica because of its hostile environment and inaccessibility. Nevertheless, many ground-based, airborne and shipborne gravity campaigns have been completed by the geophysical and geodetic communities since the 1980s. We present the first modern Antarctic-wide gravity data compilation derived from 13 million data points covering an area of 10 million km2, which corresponds to 73% coverage of the continent. The remove-compute-restore technique was applied for gridding, which facilitated levelling of the different gravity datasets with respect to an Earth Gravity Model derived from satellite data alone. The resulting free-air and Bouguer gravity anomaly grids of 10 km resolution are publicly available. These grids will enable new high-resolution combined Earth Gravity Models to be derived and represent a major step forward towards solving the geodetic polar data gap problem. They provide a new tool to investigate continental-scale lithospheric structure and geological evolution of Antarctica. PMID:29326484

Consumer perceptions of smart grid development: Results of a Hong Kong survey and policy implications

International Nuclear Information System (INIS)

Mah, Daphne Ngar-yin; Vleuten, Johannes Marinus van der; Hills, Peter; Tao, Julia

2012-01-01

Consumers have a major role to play in smart grid technologies which can be instrumental in addressing climate change and energy challenges. However, little is known about how consumers perceive, and how they might respond to the opportunities that smart grid technologies offer. This paper reports the results from a Hong Kong survey (n=505). It contributes to the literature by providing a better understanding of the perceptions and behaviour of electricity consumers about the possible deployment of smart grids. Our results indicate that Hong Kong consumers generally welcomed smart grid technologies and had a preference for energy saving, energy efficiency and renewable energy while they showed a high level of opposition to nuclear power. They displayed an interest in playing a much more informed and active role in energy decision-making, but they were sensitive to tariff increases. Motivations and barriers for consumers to support smart grid developments are also discussed. We conclude with a discussion of policy implications for effective consumer engagement. More policy attention is needed on demand-side measures, introducing institutional and regulatory changes, and modifying relationships between consumers, the government and utilities. - Highlights: ► Consumers have a major role in smart grid technologies. ► This paper reports findings of a Hong Kong survey on how consumers perceive and respond. ► Hong Kong consumers are interested in being informed and playing an active role in energy decision-making. ► Motivations and barriers are discussed. ► Policy recommendations for effective consumer engagement are suggested.

MICROARRAY IMAGE GRIDDING USING GRID LINE REFINEMENT TECHNIQUE

Directory of Open Access Journals (Sweden)

V.G. Biju

2015-05-01

Full Text Available An important stage in microarray image analysis is gridding. Microarray image gridding is done to locate sub arrays in a microarray image and find co-ordinates of spots within each sub array. For accurate identification of spots, most of the proposed gridding methods require human intervention. In this paper a fully automatic gridding method which enhances spot intensity in the preprocessing step as per a histogram based threshold method is used. The gridding step finds co-ordinates of spots from horizontal and vertical profile of the image. To correct errors due to the grid line placement, a grid line refinement technique is proposed. The algorithm is applied on different image databases and results are compared based on spot detection accuracy and time. An average spot detection accuracy of 95.06% depicts the proposed method’s flexibility and accuracy in finding the spot co-ordinates for different database images.

On the Probabilistic Deployment of Smart Grid Networks in TV White Space.

Science.gov (United States)

Cacciapuoti, Angela Sara; Caleffi, Marcello; Paura, Luigi

2016-05-10

To accommodate the rapidly increasing demand for wireless broadband communications in Smart Grid (SG) networks, research efforts are currently ongoing to enable the SG networks to utilize the TV spectrum according to the Cognitive Radio paradigm. To this aim, in this letter, we develop an analytical framework for the optimal deployment of multiple closely-located SG Neighborhood Area Networks (NANs) concurrently using the same TV spectrum. The objective is to derive the optimal values for both the number of NANs and their coverage. More specifically, regarding the number of NANs, we derive the optimal closed-form expression, i.e., the closed-form expression that assures the deployment of the maximum number of NANs in the considered region satisfying a given collision constraint on the transmissions of the NANs. Regarding the NAN coverage, we derive the optimal closed-form expression, i.e., the closed-form expression of the NAN transmission range that assures the maximum coverage of each NAN in the considered region satisfying the given collision constraint. All the theoretical results are derived by adopting a stochastic approach. Finally, numerical results validate the theoretical analysis.

Analysis of aggregation and disaggregation effects for grid-based hydrological models and the development of improved precipitation disaggregation procedures for GCMs

Directory of Open Access Journals (Sweden)

H. S. Wheater

1999-01-01

Full Text Available Appropriate representation of hydrological processes within atmospheric General Circulation Models (GCMs is important with respect to internal model dynamics (e.g. surface feedback effects on atmospheric fluxes, continental runoff production and to simulation of terrestrial impacts of climate change. However, at the scale of a GCM grid-square, several methodological problems arise. Spatial disaggregation of grid-square average climatological parameters is required in particular to produce appropriate point intensities from average precipitation. Conversely, aggregation of land surface heterogeneity is necessary for grid-scale or catchment scale application. The performance of grid-based hydrological models is evaluated for two large (104km2 UK catchments. Simple schemes, using sub-grid average of individual land use at 40 km scale and with no calibration, perform well at the annual time-scale and, with the addition of a (calibrated routing component, at the daily and monthly time-scale. Decoupling of hillslope and channel routing does not necessarily improve performance or identifiability. Scale dependence is investigated through application of distribution functions for rainfall and soil moisture at 100 km scale. The results depend on climate, but show interdependence of the representation of sub-grid rainfall and soil moisture distribution. Rainfall distribution is analysed directly using radar rainfall data from the UK and the Arkansas Red River, USA. Among other properties, the scale dependence of spatial coverage upon radar pixel resolution and GCM grid-scale, as well as the serial correlation of coverages are investigated. This leads to a revised methodology for GCM application, as a simple extension of current procedures. A new location-based approach using an image processing technique is then presented, to allow for the preservation of the spatial memory of the process.

Particle Physics could do with much more serious coverage in serious newspaper

CERN Multimedia

2004-01-01

Editorial "Particle Physics could do with much more serious coverage in serious newspaper. So we welcome the feature on the Large Hadron Collider and the computing grid that appeared in the Irish Times on 30 April. So serious is this coverage that it manages to avoid any tacky populism in its announcement of a truly earth-shattering discovery. Not blazoned across the front page, not even headlined, but tucked away in the tenth paragraph, is the news that the LHC will operate at 'minus 3000°C in temperature'. (That's minus 2727 kelvin, for thermodynamic purists -0 kelvin being absolute zero, of course.)" (fulltext)

Grid Transmission Expansion Planning Model Based on Grid Vulnerability

Science.gov (United States)

Tang, Quan; Wang, Xi; Li, Ting; Zhang, Quanming; Zhang, Hongli; Li, Huaqiang

2018-03-01

Based on grid vulnerability and uniformity theory, proposed global network structure and state vulnerability factor model used to measure different grid models. established a multi-objective power grid planning model which considering the global power network vulnerability, economy and grid security constraint. Using improved chaos crossover and mutation genetic algorithm to optimize the optimal plan. For the problem of multi-objective optimization, dimension is not uniform, the weight is not easy given. Using principal component analysis (PCA) method to comprehensive assessment of the population every generation, make the results more objective and credible assessment. the feasibility and effectiveness of the proposed model are validated by simulation results of Garver-6 bus system and Garver-18 bus.

Impact of grid impedance variations on harmonic emission of grid-connected inverters

DEFF Research Database (Denmark)

Hoseinzadeh, Bakhtyar; Bak, Claus Leth; Blaabjerg, Frede

2017-01-01

This paper addresses harmonic magnification due to resonance circuits resulting from interaction between uncertain grid impedance and converter. The source of harmonic may be either the grid or inverter. It is demonstrated that unknown and unpredictable grid impedance may result in variable...

On the uncertainties associated with using gridded rainfall data as a proxy for observed

Directory of Open Access Journals (Sweden)

C. R. Tozer

2012-05-01

Full Text Available Gridded rainfall datasets are used in many hydrological and climatological studies, in Australia and elsewhere, including for hydroclimatic forecasting, climate attribution studies and climate model performance assessments. The attraction of the spatial coverage provided by gridded data is clear, particularly in Australia where the spatial and temporal resolution of the rainfall gauge network is sparse. However, the question that must be asked is whether it is suitable to use gridded data as a proxy for observed point data, given that gridded data is inherently "smoothed" and may not necessarily capture the temporal and spatial variability of Australian rainfall which leads to hydroclimatic extremes (i.e. droughts, floods. This study investigates this question through a statistical analysis of three monthly gridded Australian rainfall datasets – the Bureau of Meteorology (BOM dataset, the Australian Water Availability Project (AWAP and the SILO dataset. The results of the monthly, seasonal and annual comparisons show that not only are the three gridded datasets different relative to each other, there are also marked differences between the gridded rainfall data and the rainfall observed at gauges within the corresponding grids – particularly for extremely wet or extremely dry conditions. Also important is that the differences observed appear to be non-systematic. To demonstrate the hydrological implications of using gridded data as a proxy for gauged data, a rainfall-runoff model is applied to one catchment in South Australia initially using gauged data as the source of rainfall input and then gridded rainfall data. The results indicate a markedly different runoff response associated with each of the different sources of rainfall data. It should be noted that this study does not seek to identify which gridded dataset is the "best" for Australia, as each gridded data source has its pros and cons, as does gauged data. Rather, the intention is

Grid interoperability: joining grid information systems

International Nuclear Information System (INIS)

Flechl, M; Field, L

2008-01-01

A grid is defined as being 'coordinated resource sharing and problem solving in dynamic, multi-institutional virtual organizations'. Over recent years a number of grid projects, many of which have a strong regional presence, have emerged to help coordinate institutions and enable grids. Today, we face a situation where a number of grid projects exist, most of which are using slightly different middleware. Grid interoperation is trying to bridge these differences and enable Virtual Organizations to access resources at the institutions independent of their grid project affiliation. Grid interoperation is usually a bilateral activity between two grid infrastructures. Recently within the Open Grid Forum, the Grid Interoperability Now (GIN) Community Group is trying to build upon these bilateral activities. The GIN group is a focal point where all the infrastructures can come together to share ideas and experiences on grid interoperation. It is hoped that each bilateral activity will bring us one step closer to the overall goal of a uniform grid landscape. A fundamental aspect of a grid is the information system, which is used to find available grid services. As different grids use different information systems, interoperation between these systems is crucial for grid interoperability. This paper describes the work carried out to overcome these differences between a number of grid projects and the experiences gained. It focuses on the different techniques used and highlights the important areas for future standardization

Comparison tomography relocation hypocenter grid search and guided grid search method in Java island

International Nuclear Information System (INIS)

Nurdian, S. W.; Adu, N.; Palupi, I. R.; Raharjo, W.

2016-01-01

The main data in this research is earthquake data recorded from 1952 to 2012 with 9162 P wave and 2426 events are recorded by 30 stations located around Java island. Relocation hypocenter processed using grid search and guidded grid search method. Then the result of relocation hypocenter become input for tomography pseudo bending inversion process. It can be used to identification the velocity distribution in subsurface. The result of relocation hypocenter by grid search and guided grid search method after tomography process shown in locally and globally. In locally area grid search method result is better than guided grid search according to geological reseach area. But in globally area the result of guided grid search method is better for a broad area because the velocity variation is more diverse than the other one and in accordance with local geological research conditions. (paper)

Progress in Grid Generation: From Chimera to DRAGON Grids

Science.gov (United States)

Liou, Meng-Sing; Kao, Kai-Hsiung

1994-01-01

Hybrid grids, composed of structured and unstructured grids, combines the best features of both. The chimera method is a major stepstone toward a hybrid grid from which the present approach is evolved. The chimera grid composes a set of overlapped structured grids which are independently generated and body-fitted, yielding a high quality grid readily accessible for efficient solution schemes. The chimera method has been shown to be efficient to generate a grid about complex geometries and has been demonstrated to deliver accurate aerodynamic prediction of complex flows. While its geometrical flexibility is attractive, interpolation of data in the overlapped regions - which in today's practice in 3D is done in a nonconservative fashion, is not. In the present paper we propose a hybrid grid scheme that maximizes the advantages of the chimera scheme and adapts the strengths of the unstructured grid while at the same time keeps its weaknesses minimal. Like the chimera method, we first divide up the physical domain by a set of structured body-fitted grids which are separately generated and overlaid throughout a complex configuration. To eliminate any pure data manipulation which does not necessarily follow governing equations, we use non-structured grids only to directly replace the region of the arbitrarily overlapped grids. This new adaptation to the chimera thinking is coined the DRAGON grid. The nonstructured grid region sandwiched between the structured grids is limited in size, resulting in only a small increase in memory and computational effort. The DRAGON method has three important advantages: (1) preserving strengths of the chimera grid; (2) eliminating difficulties sometimes encountered in the chimera scheme, such as the orphan points and bad quality of interpolation stencils; and (3) making grid communication in a fully conservative and consistent manner insofar as the governing equations are concerned. To demonstrate its use, the governing equations are

CRED 5 m Gridded bathymetry of Baker Island, Pacific Remote Island Areas, Central Pacific (Arc ASCII Format)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded (5 m cell size) bathymetry of the shelf and slope environments of Baker Island, Pacific Remote Isand Areas, Central Pacific. Almost complete bottom coverage...

Importance of Grid Center Arrangement

Science.gov (United States)

Pasaogullari, O.; Usul, N.

2012-12-01

In Digital Elevation Modeling, grid size is accepted to be the most important parameter. Despite the point density and/or scale of the source data, it is freely decided by the user. Most of the time, arrangement of the grid centers are ignored, even most GIS packages omit the choice of grid center coordinate selection. In our study; importance of the arrangement of grid centers is investigated. Using the analogy between "Raster Grid DEM" and "Bitmap Image", importance of placement of grid centers in DEMs are measured. The study has been conducted on four different grid DEMs obtained from a half ellipsoid. These grid DEMs are obtained in such a way that they are half grid size apart from each other. Resulting grid DEMs are investigated through similarity measures. Image processing scientists use different measures to investigate the dis/similarity between the images and the amount of different information they carry. Grid DEMs are projected to a finer grid in order to co-center. Similarity measures are then applied to each grid DEM pairs. These similarity measures are adapted to DEM with band reduction and real number operation. One of the measures gives function graph and the others give measure matrices. Application of similarity measures to six grid DEM pairs shows interesting results. These four different grid DEMs are created with the same method for the same area, surprisingly; thirteen out of 14 measures state that, the half grid size apart grid DEMs are different from each other. The results indicated that although grid DEMs carry mutual information, they have also additional individual information. In other words, half grid size apart constructed grid DEMs have non-redundant information.; Joint Probability Distributions Function Graphs

Chimera Grid Tools

Science.gov (United States)

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.

Towards Semantic Web Services on Large, Multi-Dimensional Coverages

Science.gov (United States)

Baumann, P.

2009-04-01

Observed and simulated data in the Earth Sciences often come as coverages, the general term for space-time varying phenomena as set forth by standardization bodies like the Open GeoSpatial Consortium (OGC) and ISO. Among such data are 1-d time series, 2-D surface data, 3-D surface data time series as well as x/y/z geophysical and oceanographic data, and 4-D metocean simulation results. With increasing dimensionality the data sizes grow exponentially, up to Petabyte object sizes. Open standards for exploiting coverage archives over the Web are available to a varying extent. The OGC Web Coverage Service (WCS) standard defines basic extraction operations: spatio-temporal and band subsetting, scaling, reprojection, and data format encoding of the result - a simple interoperable interface for coverage access. More processing functionality is available with products like Matlab, Grid-type interfaces, and the OGC Web Processing Service (WPS). However, these often lack properties known as advantageous from databases: declarativeness (describe results rather than the algorithms), safe in evaluation (no request can keep a server busy infinitely), and optimizable (enable the server to rearrange the request so as to produce the same result faster). WPS defines a geo-enabled SOAP interface for remote procedure calls. This allows to webify any program, but does not allow for semantic interoperability: a function is identified only by its function name and parameters while the semantics is encoded in the (only human readable) title and abstract. Hence, another desirable property is missing, namely an explicit semantics which allows for machine-machine communication and reasoning a la Semantic Web. The OGC Web Coverage Processing Service (WCPS) language, which has been adopted as an international standard by OGC in December 2008, defines a flexible interface for the navigation, extraction, and ad-hoc analysis of large, multi-dimensional raster coverages. It is abstract in that it

Power systems signal processing for smart grids

CERN Document Server

Ribeiro, Paulo Fernando; Ribeiro, Paulo Márcio; Cerqueira, Augusto Santiago

2013-01-01

With special relation to smart grids, this book provides clear and comprehensive explanation of how Digital Signal Processing (DSP) and Computational Intelligence (CI) techniques can be applied to solve problems in the power system. Its unique coverage bridges the gap between DSP, electrical power and energy engineering systems, showing many different techniques applied to typical and expected system conditions with practical power system examples. Surveying all recent advances on DSP for power systems, this book enables engineers and researchers to understand the current state of the art a

Smart grid security

Energy Technology Data Exchange (ETDEWEB)

Cuellar, Jorge (ed.) [Siemens AG, Muenchen (Germany). Corporate Technology

2013-11-01

The engineering, deployment and security of the future smart grid will be an enormous project requiring the consensus of many stakeholders with different views on the security and privacy requirements, not to mention methods and solutions. The fragmentation of research agendas and proposed approaches or solutions for securing the future smart grid becomes apparent observing the results from different projects, standards, committees, etc, in different countries. The different approaches and views of the papers in this collection also witness this fragmentation. This book contains the following papers: 1. IT Security Architecture Approaches for Smart Metering and Smart Grid. 2. Smart Grid Information Exchange - Securing the Smart Grid from the Ground. 3. A Tool Set for the Evaluation of Security and Reliability in Smart Grids. 4. A Holistic View of Security and Privacy Issues in Smart Grids. 5. Hardware Security for Device Authentication in the Smart Grid. 6. Maintaining Privacy in Data Rich Demand Response Applications. 7. Data Protection in a Cloud-Enabled Smart Grid. 8. Formal Analysis of a Privacy-Preserving Billing Protocol. 9. Privacy in Smart Metering Ecosystems. 10. Energy rate at home Leveraging ZigBee to Enable Smart Grid in Residential Environment.

Gridded multibeam bathymetry of Aguijan, Tinian, Farallon de Medinilla and Saipan Islands and Tatsumi and Marpi Banks, CNMI

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry shelf, bank and slope environments of Aguijan, Tinian, Farallon de Medinilla and Saipan Islands and Tatsumi and Marpi Banks, CNMI. Bottom coverage...

Grid Generation Techniques Utilizing the Volume Grid Manipulator

Science.gov (United States)

Alter, Stephen J.

1998-01-01

This paper presents grid generation techniques available in the Volume Grid Manipulation (VGM) code. The VGM code is designed to manipulate existing line, surface and volume grids to improve the quality of the data. It embodies an easy to read rich language of commands that enables such alterations as topology changes, grid adaption and smoothing. Additionally, the VGM code can be used to construct simplified straight lines, splines, and conic sections which are common curves used in the generation and manipulation of points, lines, surfaces and volumes (i.e., grid data). These simple geometric curves are essential in the construction of domain discretizations for computational fluid dynamic simulations. By comparison to previously established methods of generating these curves interactively, the VGM code provides control of slope continuity and grid point-to-point stretchings as well as quick changes in the controlling parameters. The VGM code offers the capability to couple the generation of these geometries with an extensive manipulation methodology in a scripting language. The scripting language allows parametric studies of a vehicle geometry to be efficiently performed to evaluate favorable trends in the design process. As examples of the powerful capabilities of the VGM code, a wake flow field domain will be appended to an existing X33 Venturestar volume grid; negative volumes resulting from grid expansions to enable flow field capture on a simple geometry, will be corrected; and geometrical changes to a vehicle component of the X33 Venturestar will be shown.

The Grid2003 Production Grid Principles and Practice

CERN Document Server

Foster, I; Gose, S; Maltsev, N; May, E; Rodríguez, A; Sulakhe, D; Vaniachine, A; Shank, J; Youssef, S; Adams, D; Baker, R; Deng, W; Smith, J; Yu, D; Legrand, I; Singh, S; Steenberg, C; Xia, Y; Afaq, A; Berman, E; Annis, J; Bauerdick, L A T; Ernst, M; Fisk, I; Giacchetti, L; Graham, G; Heavey, A; Kaiser, J; Kuropatkin, N; Pordes, R; Sekhri, V; Weigand, J; Wu, Y; Baker, K; Sorrillo, L; Huth, J; Allen, M; Grundhoefer, L; Hicks, J; Luehring, F C; Peck, S; Quick, R; Simms, S; Fekete, G; Van den Berg, J; Cho, K; Kwon, K; Son, D; Park, H; Canon, S; Jackson, K; Konerding, D E; Lee, J; Olson, D; Sakrejda, I; Tierney, B; Green, M; Miller, R; Letts, J; Martin, T; Bury, D; Dumitrescu, C; Engh, D; Gardner, R; Mambelli, M; Smirnov, Y; Voeckler, J; Wilde, M; Zhao, Y; Zhao, X; Avery, P; Cavanaugh, R J; Kim, B; Prescott, C; Rodríguez, J; Zahn, A; McKee, S; Jordan, C; Prewett, J; Thomas, T; Severini, H; Clifford, B; Deelman, E; Flon, L; Kesselman, C; Mehta, G; Olomu, N; Vahi, K; De, K; McGuigan, P; Sosebee, M; Bradley, D; Couvares, P; De Smet, A; Kireyev, C; Paulson, E; Roy, A; Koranda, S; Moe, B; Brown, B; Sheldon, P

2004-01-01

The Grid2003 Project has deployed a multi-virtual organization, application-driven grid laboratory ("GridS") that has sustained for several months the production-level services required by physics experiments of the Large Hadron Collider at CERN (ATLAS and CMS), the Sloan Digital Sky Survey project, the gravitational wave search experiment LIGO, the BTeV experiment at Fermilab, as well as applications in molecular structure analysis and genome analysis, and computer science research projects in such areas as job and data scheduling. The deployed infrastructure has been operating since November 2003 with 27 sites, a peak of 2800 processors, work loads from 10 different applications exceeding 1300 simultaneous jobs, and data transfers among sites of greater than 2 TB/day. We describe the principles that have guided the development of this unique infrastructure and the practical experiences that have resulted from its creation and use. We discuss application requirements for grid services deployment and configur...

Ambiguities in the grid-inefficiency correction for Frisch-Grid Ionization Chambers

International Nuclear Information System (INIS)

Al-Adili, A.; Hambsch, F.-J.; Bencardino, R.; Oberstedt, S.; Pomp, S.

2012-01-01

Ionization chambers with Frisch grids have been very successfully applied to neutron-induced fission-fragment studies during the past 20 years. They are radiation resistant and can be easily adapted to the experimental conditions. The use of Frisch grids has the advantage to remove the angular dependency from the charge induced on the anode plate. However, due to the Grid Inefficiency (GI) in shielding the charges, the anode signal remains slightly angular dependent. The correction for the GI is, however, essential to determine the correct energy of the ionizing particles. GI corrections can amount to a few percent of the anode signal. Presently, two contradicting correction methods are considered in literature. The first method adding the angular-dependent part of the signal to the signal pulse height; the second method subtracting the former from the latter. Both additive and subtractive approaches were investigated in an experiment where a Twin Frisch-Grid Ionization Chamber (TFGIC) was employed to detect the spontaneous fission fragments (FF) emitted by a 252 Cf source. Two parallel-wire grids with different wire spacing (1 and 2 mm, respectively), were used individually, in the same chamber side. All the other experimental conditions were unchanged. The 2 mm grid featured more than double the GI of the 1 mm grid. The induced charge on the anode in both measurements was compared, before and after GI correction. Before GI correction, the 2 mm grid resulted in a lower pulse-height distribution than the 1 mm grid. After applying both GI corrections to both measurements only the additive approach led to consistent grid independent pulse-height distributions. The application of the subtractive correction on the contrary led to inconsistent, grid-dependent results. It is also shown that the impact of either of the correction methods is small on the FF mass distributions of 235 U(n th , f).

A unified grid current control for grid-interactive DG inverters in microgrids

DEFF Research Database (Denmark)

Wang, Xiongfei; Loh, Poh Chiang; Blaabjerg, Frede

2015-01-01

This paper proposes a unified grid current control for grid-interactive distributed generation inverters. In the approach, the grid-side current, instead of inverter-side current, is controlled as an inner loop, while the filter capacitor voltage is indirectly regulated through a virtual admittan...... locus analyses in the discrete z-domain are performed for elaborating the controller design. Simulations and experimental results demonstrate the performances of the proposed approach.......This paper proposes a unified grid current control for grid-interactive distributed generation inverters. In the approach, the grid-side current, instead of inverter-side current, is controlled as an inner loop, while the filter capacitor voltage is indirectly regulated through a virtual admittance...... in the outer loop. It, therefore, provides several superior features over traditional control schemes: 1) high-quality grid current in the grid-connected mode, 2) inherent derivative-less virtual output impedance control, and 3) the unified active damping for both grid-connected and islanded operations. Root...

The MammoGrid Project Grids Architecture

CERN Document Server

McClatchey, Richard; Hauer, Tamas; Estrella, Florida; Saiz, Pablo; Rogulin, Dmitri; Buncic, Predrag; Clatchey, Richard Mc; Buncic, Predrag; Manset, David; Hauer, Tamas; Estrella, Florida; Saiz, Pablo; Rogulin, Dmitri

2003-01-01

The aim of the recently EU-funded MammoGrid project is, in the light of emerging Grid technology, to develop a European-wide database of mammograms that will be used to develop a set of important healthcare applications and investigate the potential of this Grid to support effective co-working between healthcare professionals throughout the EU. The MammoGrid consortium intends to use a Grid model to enable distributed computing that spans national borders. This Grid infrastructure will be used for deploying novel algorithms as software directly developed or enhanced within the project. Using the MammoGrid clinicians will be able to harness the use of massive amounts of medical image data to perform epidemiological studies, advanced image processing, radiographic education and ultimately, tele-diagnosis over communities of medical "virtual organisations". This is achieved through the use of Grid-compliant services [1] for managing (versions of) massively distributed files of mammograms, for handling the distri...

CRED 20m Gridded bathymetry and IKONOS estimated depths of Pearl and Hermes Atoll, Hawaii, USA (Arc ASCII format)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry and IKONOS estimated depths of the shelf and slope environments of Pearl and Hermes Atoll, Hawaii, USA. Bottom coverage was achieved in depths...

CRED 5 m Gridded bathymetry and IKONOS estimated depths of Pearl and Hermes Atoll, Hawaii, USA (Arc ASCII format)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry and IKONOS estimated depths of the shelf and slope environments of Pearl and Hermes Atoll, Hawaii, USA. Bottom coverage was achieved in depths...

CRED 20 m Gridded bathymetry and IKONOS estimated depths of Pearl and Hermes Atoll, Hawaii, USA (NetCDF format)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry and IKONOS estimated depths of the shelf and slope environments of Pearl and Hermes Atoll, Hawaii, USA. Bottom coverage was achieved in depths...

CRED 5 m Gridded bathymetry and IKONOS estimated depths of Pearl and Hermes Atoll, Hawaii, USA (NetCDF format)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry and IKONOS estimated depths of the shelf and slope environments of Pearl and Hermes Atoll, Hawaii, USA. Bottom coverage was achieved in depths...

Calculation approaches for grid usage fees to influence the load curve in the distribution grid level

International Nuclear Information System (INIS)

Illing, Bjoern

2014-01-01

Dominated by the energy policy the decentralized German energy market is changing. One mature target of the government is to increase the contribution of renewable generation to the gross electricity consumption. In order to achieve this target disadvantages like an increased need for capacity management occurs. Load reduction and variable grid fees offer the grid operator solutions to realize capacity management by influencing the load profile. The evolution of the current grid fees towards more causality is required to adapt these approaches. Two calculation approaches are developed in this assignment. On the one hand multivariable grid fees keeping the current components demand and energy charge. Additional to the grid costs grid load dependent parameters like the amount of decentralized feed-ins, time and local circumstances as well as grid capacities are considered. On the other hand the grid fee flat-rate which represents a demand based model on a monthly level. Both approaches are designed to meet the criteria for future grid fees. By means of a case study the effects of the grid fees on the load profile at the low voltage grid is simulated. Thereby the consumption is represented by different behaviour models and the results are scaled at the benchmark grid area. The resulting load curve is analyzed concerning the effects of peak load reduction as well as the integration of renewable energy sources. Additionally the combined effect of grid fees and electricity tariffs is evaluated. Finally the work discusses the launching of grid fees in the tense atmosphere of politics, legislation and grid operation. Results of this work are two calculation approaches designed for grid operators to define the grid fees. Multivariable grid fees are based on the current calculation scheme. Hereby demand and energy charges are weighted by time, locational and load related dependencies. The grid fee flat-rate defines a limitation in demand extraction. Different demand levels

Grid Data Management and Customer Demands at MeteoSwiss

Science.gov (United States)

Rigo, G.; Lukasczyk, Ch.

2010-09-01

Data grids constitute the required input form for a variety of applications. Therefore, customers increasingly expect climate services to not only provide measured data, but also grids of these with the required configurations on an operational basis. Currently, MeteoSwiss is establishing a production chain for delivering data grids by subscription directly from the data warehouse in order to meet the demand for precipitation data grids by governmental, business and science customers. The MeteoSwiss data warehouse runs on an Oracle database linked with an ArcGIS Standard edition geodatabase. The grids are produced by Unix-based software written in R called GRIDMCH which extracts the station data from the data warehouse and stores the files in the file system. By scripts, the netcdf-v4 files are imported via an FME interface into the database. Currently daily and monthly deliveries of daily precipitation grids are available from MeteoSwiss with a spatial resolution of 2.2km x 2.2km. These daily delivered grids are a preliminary based on 100 measuring sites whilst the grid of the monthly delivery of daily sums is calculated out of about 430 stations. Crucial for the absorption by the customers is the understanding of and the trust into the new grid product. Clearly stating needs which can be covered by grid products, the customers require a certain lead time to develop applications making use of the particular grid. Therefore, early contacts and a continuous attendance as well as flexibility in adjusting the production process to fulfill emerging customer needs are important during the introduction period. Gridding over complex terrain can lead to temporally elevated uncertainties in certain areas depending on the weather situation and coverage of measurements. Therefore, careful instructions on the quality and use and the possibility to communicate the uncertainties of gridded data proofed to be essential especially to the business and science customers who require

A mass campaign too often? results of a vaccination coverage ...

African Journals Online (AJOL)

Objectives. To determine the routine and mass immunisation coverage in children aged between 12 and 23 months in the Dikgale-Soekmekaar district, Northern Province, South Africa. Design. Cross-sectional community-based vaccination prevalence survey using a two-stage cluster sampling technique. Methods. Data on ...

A Generic Danish Distribution Grid Model for Smart Grid Technology Testing

DEFF Research Database (Denmark)

Cha, Seung-Tae; Wu, Qiuwei; Østergaard, Jacob

2012-01-01

This paper describes the development of a generic Danish distribution grid model for smart grid technology testing based on the Bornholm power system. The frequency dependent network equivalent (FDNE) method has been used in order to accurately preserve the desired properties and characteristics...... as a generic Smart Grid benchmark model for testing purposes....... by comparing the transient response of the original Bornholm power system model and the developed generic model under significant fault conditions. The results clearly show that the equivalent generic distribution grid model retains the dynamic characteristics of the original system, and can be used...

CRED 60 m Gridded bathymetry and IKONOS estimated depths of UTM Zone 2, Northwestern Hawaiian Islands, USA (NetCDF format)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry and IKONOS estimated depths of the shelf and slope environments of the Northwestern Hawaiian Islands, USA within UTM Zone 2. Bottom coverage was...

CRED 60 m Gridded bathymetry and IKONOS estimated depths of UTM Zone 2, Northwestern Hawaiian Islands, USA (Arc ASCII format)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry and IKONOS estimated depths of the shelf and slope environments of the Northwestern Hawaiian Islands, USA within UTM Zone 2. Bottom coverage was...

CRED 60m Gridded bathymetry and IKONOS estimated depths of UTM Zone 3, Northwestern Hawaiian Islands, USA (Arc ASCII format)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry and IKONOS estimated depths of the shelf and slope environments of the Northwestern Hawaiian Islands, USA within UTM Zone 3. Bottom coverage was...

CRED 60 m Gridded bathymetry and IKONOS estimated depths of UTM Zone 3, Northwestern Hawaiian Islands, USA (netCDF format)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry and IKONOS estimated depths of the shelf and slope environments of the Northwestern Hawaiian Islands, USA within UTM Zone 3. Bottom coverage was...

CRED 60 m Gridded bathymetry and IKONOS estimated depths of UTM Zone 1, Northwestern Hawaiian Islands, USA (NetCDF format)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Gridded bathymetry and IKONOS estimated depths of the shelf and slope environments of the Northwestern Hawaiian Islands, USA within UTM Zone 1. Bottom coverage was...

Implementation of grid-connected to/from off-grid transference for micro-grid inverters

OpenAIRE

Heredero Peris, Daniel; Chillón Antón, Cristian; Pages Gimenez, Marc; Gross, Gabriel Igor; Montesinos Miracle, Daniel

2013-01-01

This paper presents the transfer of a microgrid converter from/to on-grid to/from off-grid when the converter is working in two different modes. In the first transfer presented method, the converter operates as a Current Source Inverter (CSI) when on-grid and as a Voltage Source Inverter (VSI) when off-grid. In the second transfer method, the converter is operated as a VSI both, when operated on-grid and off-grid. The two methods are implemented successfully in a real pla...

Multi-Grid detector for neutron spectroscopy: results obtained on time-of-flight spectrometer CNCS

Science.gov (United States)

Anastasopoulos, M.; Bebb, R.; Berry, K.; Birch, J.; Bryś, T.; Buffet, J.-C.; Clergeau, J.-F.; Deen, P. P.; Ehlers, G.; van Esch, P.; Everett, S. M.; Guerard, B.; Hall-Wilton, R.; Herwig, K.; Hultman, L.; Höglund, C.; Iruretagoiena, I.; Issa, F.; Jensen, J.; Khaplanov, A.; Kirstein, O.; Lopez Higuera, I.; Piscitelli, F.; Robinson, L.; Schmidt, S.; Stefanescu, I.

2017-04-01

The Multi-Grid detector technology has evolved from the proof-of-principle and characterisation stages. Here we report on the performance of the Multi-Grid detector, the MG.CNCS prototype, which has been installed and tested at the Cold Neutron Chopper Spectrometer, CNCS at SNS. This has allowed a side-by-side comparison to the performance of 3He detectors on an operational instrument. The demonstrator has an active area of 0.2 m2. It is specifically tailored to the specifications of CNCS. The detector was installed in June 2016 and has operated since then, collecting neutron scattering data in parallel to the He-3 detectors of CNCS. In this paper, we present a comprehensive analysis of this data, in particular on instrument energy resolution, rate capability, background and relative efficiency. Stability, gamma-ray and fast neutron sensitivity have also been investigated. The effect of scattering in the detector components has been measured and provides input to comparison for Monte Carlo simulations. All data is presented in comparison to that measured by the 3He detectors simultaneously, showing that all features recorded by one detector are also recorded by the other. The energy resolution matches closely. We find that the Multi-Grid is able to match the data collected by 3He, and see an indication of a considerable advantage in the count rate capability. Based on these results, we are confident that the Multi-Grid detector will be capable of producing high quality scientific data on chopper spectrometers utilising the unprecedented neutron flux of the ESS.

Sustainable Power Supply Solutions for Off-Grid Base Stations

Directory of Open Access Journals (Sweden)

Asma Mohamad Aris

2015-09-01

Full Text Available The telecommunication sector plays a significant role in shaping the global economy and the way people share information and knowledge. At present, the telecommunication sector is liable for its energy consumption and the amount of emissions it emits in the environment. In the context of off-grid telecommunication applications, off-grid base stations (BSs are commonly used due to their ability to provide radio coverage over a wide geographic area. However, in the past, the off-grid BSs usually relied on emission-intensive power supply solutions such as diesel generators. In this review paper, various types of solutions (including, in particular, the sustainable solutions for powering BSs are discussed. The key aspects in designing an ideal power supply solution are reviewed, and these mainly include the pre-feasibility study and the thermal management of BSs, which comprise heating and cooling of the BS shelter/cabinets and BS electronic equipment and power supply components. The sizing and optimization approaches used to design the BSs’ power supply systems as well as the operational and control strategies adopted to manage the power supply systems are also reviewed in this paper.

CEOS Ocean Variables Enabling Research and Applications for Geo (COVERAGE)

Science.gov (United States)

Tsontos, V. M.; Vazquez, J.; Zlotnicki, V.

2017-12-01

The CEOS Ocean Variables Enabling Research and Applications for GEO (COVERAGE) initiative seeks to facilitate joint utilization of different satellite data streams on ocean physics, better integrated with biological and in situ observations, including near real-time data streams in support of oceanographic and decision support applications for societal benefit. COVERAGE aligns with programmatic objectives of CEOS (the Committee on Earth Observation Satellites) and the missions of GEO-MBON (Marine Biodiversity Observation Network) and GEO-Blue Planet, which are to advance and exploit synergies among the many observational programs devoted to ocean and coastal waters. COVERAGE is conceived of as 3 year pilot project involving international collaboration. It focuses on implementing technologies, including cloud based solutions, to provide a data rich, web-based platform for integrated ocean data delivery and access: multi-parameter observations, easily discoverable and usable, organized by disciplines, available in near real-time, collocated to a common grid and including climatologies. These will be complemented by a set of value-added data services available via the COVERAGE portal including an advanced Web-based visualization interface, subsetting/extraction, data collocation/matchup and other relevant on demand processing capabilities. COVERAGE development will be organized around priority use cases and applications identified by GEO and agency partners. The initial phase will be to develop co-located 25km products from the four Ocean Virtual Constellations (VCs), Sea Surface Temperature, Sea Level, Ocean Color, and Sea Surface Winds. This aims to stimulate work among the ocean VCs while developing products and system functionality based on community recommendations. Such products as anomalies from a time mean, would build on the theme of applications with a relevance to CEOS/GEO mission and vision. Here we provide an overview of the COVERAGE initiative with an

Assessment of the value of electricity grids - Results of an investigation using enterprise data

International Nuclear Information System (INIS)

Schaerer, M.; Kaufmann, I.; Flury, R.

2002-01-01

This report for the Swiss Federal Office of Energy (SFOE) presents the results of a study made on the effects of different ways of evaluating the transmission fees for the use of electricity grids as foreseen in Swiss legislation on electricity market liberalisation. The study was made using enterprise data supplied by various distribution utilities. The sensitivity analysis made, with the capital costs of the grids as its kernel, is described. Four variants based on different combinations of basic assessment data and rates of interest are presented. The availability and quality of data is discussed, as is the large number of different utility types to be found in Switzerland. For the interpretation of the results of the study, two primary points of view are considered - that of the utility, focussed on future investments and their financing, and that of the consumer, focussed on pricing aspects. The report is concluded with recommendations on which models should be proposed for a future electricity market decree

Smart grid

International Nuclear Information System (INIS)

Choi, Dong Bae

2001-11-01

This book describes press smart grid from basics to recent trend. It is divided into ten chapters, which deals with smart grid as green revolution in energy with introduction, history, the fields, application and needed technique for smart grid, Trend of smart grid in foreign such as a model business of smart grid in foreign, policy for smart grid in U.S.A, Trend of smart grid in domestic with international standard of smart grid and strategy and rood map, smart power grid as infrastructure of smart business with EMS development, SAS, SCADA, DAS and PQMS, smart grid for smart consumer, smart renewable like Desertec project, convergence IT with network and PLC, application of an electric car, smart electro service for realtime of electrical pricing system, arrangement of smart grid.

GridCom, Grid Commander: graphical interface for Grid jobs and data management

International Nuclear Information System (INIS)

Galaktionov, V.V.

2011-01-01

GridCom - the software package for maintenance of automation of access to means of distributed system Grid (jobs and data). The client part, executed in the form of Java-applets, realises the Web-interface access to Grid through standard browsers. The executive part Lexor (LCG Executor) is started by the user in UI (User Interface) machine providing performance of Grid operations

A Novel Energy Efficient Topology Control Scheme Based on a Coverage-Preserving and Sleep Scheduling Model for Sensor Networks.

Science.gov (United States)

Shi, Binbin; Wei, Wei; Wang, Yihuai; Shu, Wanneng

2016-10-14

In high-density sensor networks, scheduling some sensor nodes to be in the sleep mode while other sensor nodes remain active for monitoring or forwarding packets is an effective control scheme to conserve energy. In this paper, a Coverage-Preserving Control Scheduling Scheme (CPCSS) based on a cloud model and redundancy degree in sensor networks is proposed. Firstly, the normal cloud model is adopted for calculating the similarity degree between the sensor nodes in terms of their historical data, and then all nodes in each grid of the target area can be classified into several categories. Secondly, the redundancy degree of a node is calculated according to its sensing area being covered by the neighboring sensors. Finally, a centralized approximation algorithm based on the partition of the target area is designed to obtain the approximate minimum set of nodes, which can retain the sufficient coverage of the target region and ensure the connectivity of the network at the same time. The simulation results show that the proposed CPCSS can balance the energy consumption and optimize the coverage performance of the sensor network.

Pyramid solar micro-grid

Science.gov (United States)

Huang, Bin-Juine; Hsu, Po-Chien; Wang, Yi-Hung; Tang, Tzu-Chiao; Wang, Jia-Wei; Dong, Xin-Hong; Hsu, Hsin-Yi; Li, Kang; Lee, Kung-Yen

2018-03-01

A novel pyramid solar micro-grid is proposed in the present study. All the members within the micro-grid can mutually share excess solar PV power each other through a binary-connection hierarchy. The test results of a 2+2 pyramid solar micro-grid consisting of 4 individual solar PV systems for self-consumption are reported.

Coverage of Large-Scale Food Fortification of Edible Oil, Wheat Flour, and Maize Flour Varies Greatly by Vehicle and Country but Is Consistently Lower among the Most Vulnerable: Results from Coverage Surveys in 8 Countries.

Science.gov (United States)

Aaron, Grant J; Friesen, Valerie M; Jungjohann, Svenja; Garrett, Greg S; Neufeld, Lynnette M; Myatt, Mark

2017-05-01

Background: Large-scale food fortification (LSFF) of commonly consumed food vehicles is widely implemented in low- and middle-income countries. Many programs have monitoring information gaps and most countries fail to assess program coverage. Objective: The aim of this work was to present LSFF coverage survey findings (overall and in vulnerable populations) from 18 programs (7 wheat flour, 4 maize flour, and 7 edible oil programs) conducted in 8 countries between 2013 and 2015. Methods: A Fortification Assessment Coverage Toolkit (FACT) was developed to standardize the assessments. Three indicators were used to assess the relations between coverage and vulnerability: 1 ) poverty, 2 ) poor dietary diversity, and 3 ) rural residence. Three measures of coverage were assessed: 1 ) consumption of the vehicle, 2 ) consumption of a fortifiable vehicle, and 3 ) consumption of a fortified vehicle. Individual program performance was assessed based on the following: 1 ) achieving overall coverage ≥50%, 2) achieving coverage of ≥75% in ≥1 vulnerable group, and 3 ) achieving equity in coverage for ≥1 vulnerable group. Results: Coverage varied widely by food vehicle and country. Only 2 of the 18 LSFF programs assessed met all 3 program performance criteria. The 2 main program bottlenecks were a poor choice of vehicle and failure to fortify a fortifiable vehicle (i.e., absence of fortification). Conclusions: The results highlight the importance of sound program design and routine monitoring and evaluation. There is strong evidence of the impact and cost-effectiveness of LSFF; however, impact can only be achieved when the necessary activities and processes during program design and implementation are followed. The FACT approach fills an important gap in the availability of standardized tools. The LSFF programs assessed here need to be re-evaluated to determine whether to further invest in the programs, whether other vehicles are appropriate, and whether other approaches

Desktop grid computing

CERN Document Server

Cerin, Christophe

2012-01-01

Desktop Grid Computing presents common techniques used in numerous models, algorithms, and tools developed during the last decade to implement desktop grid computing. These techniques enable the solution of many important sub-problems for middleware design, including scheduling, data management, security, load balancing, result certification, and fault tolerance. The book's first part covers the initial ideas and basic concepts of desktop grid computing. The second part explores challenging current and future problems. Each chapter presents the sub-problems, discusses theoretical and practical

Grid simulator for power quality assessment of micro-grids

DEFF Research Database (Denmark)

Carrasco, Joaquin Eloy Garcia; Vasquez, Juan Carlos; Guerrero, Josep M.

2013-01-01

voltages, low-order harmonics and flicker. The aim of this equipment is to test the performance of a given system under such distorted voltages. A prototype of the simulator, consisting of two inverters connected back-to-back to a 380 V three-phase grid and feeding a micro-grid composed of two......-inverter interfaced distributed generators and a critical load was built and tested. A set of experimental results for linear purely resistive loads, non-linear loads and current-controlled inverters is presented to prove the capabilities of the simulator. Finally, a case study is presented by testing a micro-grid.......In this study, a grid simulator based on a back-to-back inverter topology with resonant controllers is presented. The simulator is able to generate three-phase voltages for a range of amplitudes and frequencies with different types of perturbations, such as voltage sags, steady-state unbalanced...

Urban micro-grids

International Nuclear Information System (INIS)

Faure, Maeva; Salmon, Martin; El Fadili, Safae; Payen, Luc; Kerlero, Guillaume; Banner, Arnaud; Ehinger, Andreas; Illouz, Sebastien; Picot, Roland; Jolivet, Veronique; Michon Savarit, Jeanne; Strang, Karl Axel

2017-02-01

ENEA Consulting published the results of a study on urban micro-grids conducted in partnership with the Group ADP, the Group Caisse des Depots, ENEDIS, Omexom, Total and the Tuck Foundation. This study offers a vision of the definition of an urban micro-grid, the value brought by a micro-grid in different contexts based on real case studies, and the upcoming challenges that micro-grid stakeholders will face (regulation, business models, technology). The electric production and distribution system, as the backbone of an increasingly urbanized and energy dependent society, is urged to shift towards a more resilient, efficient and environment-friendly infrastructure. Decentralisation of electricity production into densely populated areas is a promising opportunity to achieve this transition. A micro-grid enhances local production through clustering electricity producers and consumers within a delimited electricity network; it has the ability to disconnect from the main grid for a limited period of time, offering an energy security service to its customers during grid outages for example. However: The islanding capability is an inherent feature of the micro-grid concept that leads to a significant premium on electricity cost, especially in a system highly reliant on intermittent electricity production. In this case, a smart grid, with local energy production and no islanding capability, can be customized to meet relevant sustainability and cost savings goals at lower costs For industrials, urban micro-grids can be economically profitable in presence of high share of reliable energy production and thermal energy demand micro-grids face strong regulatory challenges that should be overcome for further development Whether islanding is or is not implemented into the system, end-user demand for a greener, more local, cheaper and more reliable energy, as well as additional services to the grid, are strong drivers for local production and consumption. In some specific cases

Enabling Campus Grids with Open Science Grid Technology

International Nuclear Information System (INIS)

Weitzel, Derek; Fraser, Dan; Pordes, Ruth; Bockelman, Brian; Swanson, David

2011-01-01

The Open Science Grid is a recognized key component of the US national cyber-infrastructure enabling scientific discovery through advanced high throughput computing. The principles and techniques that underlie the Open Science Grid can also be applied to Campus Grids since many of the requirements are the same, even if the implementation technologies differ. We find five requirements for a campus grid: trust relationships, job submission, resource independence, accounting, and data management. The Holland Computing Center's campus grid at the University of Nebraska-Lincoln was designed to fulfill the requirements of a campus grid. A bridging daemon was designed to bring non-Condor clusters into a grid managed by Condor. Condor features which make it possible to bridge Condor sites into a multi-campus grid have been exploited at the Holland Computing Center as well.

Implementation of a Multi-Robot Coverage Algorithm on a Two-Dimensional, Grid-Based Environment

Science.gov (United States)

2017-06-01

different approaches is based on “ behavior -based” versus “system theory based” approaches to the problem. 1. Behavior –Based Approach Most behavior -based...otherwise, it performs the behavior of IG. This kind of algorithm could be classified as a system theory based approach since the change in the...systems, robot agents are likely to take over mine countermeasure (MCM) missions one day. The path planning coverage algorithm is an essential topic for

Assessment of grid optimisation measures for the German transmission grid using open source grid data

Science.gov (United States)

Böing, F.; Murmann, A.; Pellinger, C.; Bruckmeier, A.; Kern, T.; Mongin, T.

2018-02-01

The expansion of capacities in the German transmission grid is a necessity for further integration of renewable energy sources into the electricity sector. In this paper, the grid optimisation measures ‘Overhead Line Monitoring’, ‘Power-to-Heat’ and ‘Demand Response in the Industry’ are evaluated and compared against conventional grid expansion for the year 2030. Initially, the methodical approach of the simulation model is presented and detailed descriptions of the grid model and the used grid data, which partly originates from open-source platforms, are provided. Further, this paper explains how ‘Curtailment’ and ‘Redispatch’ can be reduced by implementing grid optimisation measures and how the depreciation of economic costs can be determined considering construction costs. The developed simulations show that the conventional grid expansion is more efficient and implies more grid relieving effects than the evaluated grid optimisation measures.

Al-doped ZnO/Ag grid hybrid transparent conductive electrodes fabricated using a low-temperature process

Energy Technology Data Exchange (ETDEWEB)

An, Ha-Rim; Oh, Sung-Tag [Department of Materials Science and Engineering, Seoul National University of Science and Technology, Seoul 139-743 (Korea, Republic of); Kim, Chang Yeoul [Future Convergence Ceramic Division, Korea Institute Ceramic Engineering and Technology (KICET), Seoul 233-5 (Korea, Republic of); Baek, Seong-Ho [Energy Research Division, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 711-873 (Korea, Republic of); Park, Il-Kyu, E-mail: ikpark@ynu.ac.kr [Department of Electronic Engineering, Yeungnam University, Gyeongbuk 712-749 (Korea, Republic of); Ahn, Hyo-Jin, E-mail: hjahn@seoultech.ac.kr [Department of Materials Science and Engineering, Seoul National University of Science and Technology, Seoul 139-743 (Korea, Republic of)

2014-12-05

Highlights: • Al-doped ZnO/Ag transparent conductive electrode is fabricated at low temperature. • Performance of the hybrid transparent conductive electrode affected by the structure. • The performance enhancement mechanism is suggested. - Abstract: Al-doped ZnO (AZO)/Ag grid hybrid transparent conductive electrode (TCE) structures were fabricated at a low temperature by using electrohydrodynamic jet printing for the Ag grids and atomic layer deposition for the AZO layers. The structural investigations showed that the AZO/Ag grid hybrid structures consisted of Ag grid lines formed by Ag particles and the AZO layer covering the inter-spacing between the Ag grid lines. The Ag particles comprising the Ag grid lines were also capped by thin AZO layers, and the coverage of the AZO layers was increased with increasing the thickness of the AZO layer. Using the optimum thickness of AZO layer of 70 nm, the hybrid TCE structure showed an electrical resistivity of 5.45 × 10{sup −5} Ω cm, an optical transmittance of 80.80%, and a figure of merit value of 1.41 × 10{sup −2} Ω{sup −1}. The performance enhancement was suggested based on the microstructural investigations on the AZO/Ag grid hybrid structures.

Using Multiple Monthly Water Balance Models to Evaluate Gridded Precipitation Products over Peninsular Spain

Directory of Open Access Journals (Sweden)

Javier Senent-Aparicio

2018-06-01

Full Text Available The availability of precipitation data is the key driver in the application of hydrological models when simulating streamflow. Ground weather stations are regularly used to measure precipitation. However, spatial coverage is often limited in low-population areas and mountain areas. To overcome this limitation, gridded datasets from remote sensing have been widely used. This study evaluates four widely used global precipitation datasets (GPDs: The Tropical Rainfall Measuring Mission (TRMM 3B43, the Climate Forecast System Reanalysis (CFSR, the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN, and the Multi-Source Weighted-Ensemble Precipitation (MSWEP, against point gauge and gridded dataset observations using multiple monthly water balance models (MWBMs in four different meso-scale basins that cover the main climatic zones of Peninsular Spain. The volumes of precipitation obtained from the GPDs tend to be smaller than those from the gauged data. Results underscore the superiority of the national gridded dataset, although the TRMM provides satisfactory results in simulating streamflow, reaching similar Nash-Sutcliffe values, between 0.70 and 0.95, and an average total volume error of 12% when using the GR2M model. The performance of GPDs highly depends on the climate, so that the more humid the watershed is, the better results can be achieved. The procedures used can be applied in regions with similar case studies to more accurately assess the resources within a system in which there is scarcity of recorded data available.

Enabling campus grids with open science grid technology

Energy Technology Data Exchange (ETDEWEB)

Weitzel, Derek [Nebraska U.; Bockelman, Brian [Nebraska U.; Swanson, David [Nebraska U.; Fraser, Dan [Argonne; Pordes, Ruth [Fermilab

2011-01-01

The Open Science Grid is a recognized key component of the US national cyber-infrastructure enabling scientific discovery through advanced high throughput computing. The principles and techniques that underlie the Open Science Grid can also be applied to Campus Grids since many of the requirements are the same, even if the implementation technologies differ. We find five requirements for a campus grid: trust relationships, job submission, resource independence, accounting, and data management. The Holland Computing Center's campus grid at the University of Nebraska-Lincoln was designed to fulfill the requirements of a campus grid. A bridging daemon was designed to bring non-Condor clusters into a grid managed by Condor. Condor features which make it possible to bridge Condor sites into a multi-campus grid have been exploited at the Holland Computing Center as well.

Coverage of Large-Scale Food Fortification of Edible Oil, Wheat Flour, and Maize Flour Varies Greatly by Vehicle and Country but Is Consistently Lower among the Most Vulnerable: Results from Coverage Surveys in 8 Countries123

Science.gov (United States)

Aaron, Grant J; Friesen, Valerie M; Jungjohann, Svenja; Garrett, Greg S; Myatt, Mark

2017-01-01

Background: Large-scale food fortification (LSFF) of commonly consumed food vehicles is widely implemented in low- and middle-income countries. Many programs have monitoring information gaps and most countries fail to assess program coverage. Objective: The aim of this work was to present LSFF coverage survey findings (overall and in vulnerable populations) from 18 programs (7 wheat flour, 4 maize flour, and 7 edible oil programs) conducted in 8 countries between 2013 and 2015. Methods: A Fortification Assessment Coverage Toolkit (FACT) was developed to standardize the assessments. Three indicators were used to assess the relations between coverage and vulnerability: 1) poverty, 2) poor dietary diversity, and 3) rural residence. Three measures of coverage were assessed: 1) consumption of the vehicle, 2) consumption of a fortifiable vehicle, and 3) consumption of a fortified vehicle. Individual program performance was assessed based on the following: 1) achieving overall coverage ≥50%, 2) achieving coverage of ≥75% in ≥1 vulnerable group, and 3) achieving equity in coverage for ≥1 vulnerable group. Results: Coverage varied widely by food vehicle and country. Only 2 of the 18 LSFF programs assessed met all 3 program performance criteria. The 2 main program bottlenecks were a poor choice of vehicle and failure to fortify a fortifiable vehicle (i.e., absence of fortification). Conclusions: The results highlight the importance of sound program design and routine monitoring and evaluation. There is strong evidence of the impact and cost-effectiveness of LSFF; however, impact can only be achieved when the necessary activities and processes during program design and implementation are followed. The FACT approach fills an important gap in the availability of standardized tools. The LSFF programs assessed here need to be re-evaluated to determine whether to further invest in the programs, whether other vehicles are appropriate, and whether other approaches are needed

Challenges in Estimating Vaccine Coverage in Refugee and Displaced Populations: Results From Household Surveys in Jordan and Lebanon

Science.gov (United States)

Roberton, Timothy; Weiss, William; Doocy, Shannon

2017-01-01

Ensuring the sustained immunization of displaced persons is a key objective in humanitarian emergencies. Typically, humanitarian actors measure coverage of single vaccines following an immunization campaign; few measure routine coverage of all vaccines. We undertook household surveys of Syrian refugees in Jordan and Lebanon, outside of camps, using a mix of random and respondent-driven sampling, to measure coverage of all vaccinations included in the host country’s vaccine schedule. We analyzed the results with a critical eye to data limitations and implications for similar studies. Among households with a child aged 12–23 months, 55.1% of respondents in Jordan and 46.6% in Lebanon were able to produce the child’s EPI card. Only 24.5% of Syrian refugee children in Jordan and 12.5% in Lebanon were fully immunized through routine vaccination services (having received from non-campaign sources: measles, polio 1–3, and DPT 1–3 in Jordan and Lebanon, and BCG in Jordan). Respondents in Jordan (33.5%) and Lebanon (40.1%) reported difficulties obtaining child vaccinations. Our estimated immunization rates were lower than expected and raise serious concerns about gaps in vaccine coverage among Syrian refugees. Although our estimates likely under-represent true coverage, given the additional benefit of campaigns (not captured in our surveys), there is a clear need to increase awareness, accessibility, and uptake of immunization services. Current methods to measure vaccine coverage in refugee and displaced populations have limitations. To better understand health needs in such groups, we need research on: validity of recall methods, links between campaigns and routine immunization programs, and improved sampling of hard-to-reach populations. PMID:28805672

GridCom, Grid Commander: graphical interface for Grid jobs and data management; GridCom, Grid Commander: graficheskij interfejs dlya raboty s zadachami i dannymi v gride

Energy Technology Data Exchange (ETDEWEB)

Galaktionov, V V

2011-07-01

GridCom - the software package for maintenance of automation of access to means of distributed system Grid (jobs and data). The client part, executed in the form of Java-applets, realises the Web-interface access to Grid through standard browsers. The executive part Lexor (LCG Executor) is started by the user in UI (User Interface) machine providing performance of Grid operations

Vertical grid of retrieved atmospheric profiles

International Nuclear Information System (INIS)

Ceccherini, Simone; Carli, Bruno; Raspollini, Piera

2016-01-01

The choice of the vertical grid of atmospheric profiles retrieved from remote sensing observations is discussed considering the two cases of profiles used to represent the results of individual measurements and of profiles used for subsequent data fusion applications. An ozone measurement of the MIPAS instrument is used to assess, for different vertical grids, the quality of the retrieved profiles in terms of profile values, retrieval errors, vertical resolutions and number of degrees of freedom. In the case of individual retrievals no evident advantage is obtained with the use of a grid finer than the one with a reduced number of grid points, which are optimized according to the information content of the observations. Nevertheless, this instrument dependent vertical grid, which seems to extract all the available information, provides very poor results when used for data fusion applications. A loss of about a quarter of the degrees of freedom is observed when the data fusion is made using the instrument dependent vertical grid relative to the data fusion made using a vertical grid optimized for the data fusion product. This result is explained by the analysis of the eigenvalues of the Fisher information matrix and leads to the conclusion that different vertical grids must be adopted when data fusion is the expected application. - Highlights: • Data fusion application is taken into account for the choice of the vertical grid. • The study is performed using ozone profiles retrieved from MIPAS measurements. • A very fine vertical grid is not needed for the analysis of a single instrument. • The instrument dependent vertical grid is not the best choice for data fusion. • A data fusion dependent vertical grid must be used for profiles that will be fused.

FastSLAM Using Compressed Occupancy Grids

Directory of Open Access Journals (Sweden)

Christopher Cain

2016-01-01

Full Text Available Robotic vehicles working in unknown environments require the ability to determine their location while learning about obstacles located around them. In this paper a method of solving the SLAM problem that makes use of compressed occupancy grids is presented. The presented approach is an extension of the FastSLAM algorithm which stores a compressed form of the occupancy grid to reduce the amount of memory required to store the set of occupancy grids maintained by the particle filter. The performance of the algorithm is presented using experimental results obtained using a small inexpensive ground vehicle equipped with LiDAR, compass, and downward facing camera that provides the vehicle with visual odometry measurements. The presented results demonstrate that although with our approach the occupancy grid maintained by each particle uses only 40% of the data needed to store the uncompressed occupancy grid, we can still achieve almost identical results to the approach where each particle filter stores the full occupancy grid.

Monitoring intervention coverage in the context of universal health coverage.

Directory of Open Access Journals (Sweden)

Ties Boerma

2014-09-01

Full Text Available Monitoring universal health coverage (UHC focuses on information on health intervention coverage and financial protection. This paper addresses monitoring intervention coverage, related to the full spectrum of UHC, including health promotion and disease prevention, treatment, rehabilitation, and palliation. A comprehensive core set of indicators most relevant to the country situation should be monitored on a regular basis as part of health progress and systems performance assessment for all countries. UHC monitoring should be embedded in a broad results framework for the country health system, but focus on indicators related to the coverage of interventions that most directly reflect the results of UHC investments and strategies in each country. A set of tracer coverage indicators can be selected, divided into two groups-promotion/prevention, and treatment/care-as illustrated in this paper. Disaggregation of the indicators by the main equity stratifiers is critical to monitor progress in all population groups. Targets need to be set in accordance with baselines, historical rate of progress, and measurement considerations. Critical measurement gaps also exist, especially for treatment indicators, covering issues such as mental health, injuries, chronic conditions, surgical interventions, rehabilitation, and palliation. Consequently, further research and proxy indicators need to be used in the interim. Ideally, indicators should include a quality of intervention dimension. For some interventions, use of a single indicator is feasible, such as management of hypertension; but in many areas additional indicators are needed to capture quality of service provision. The monitoring of UHC has significant implications for health information systems. Major data gaps will need to be filled. At a minimum, countries will need to administer regular household health surveys with biological and clinical data collection. Countries will also need to improve the

Development of a High Performance Spacer Grid

Energy Technology Data Exchange (ETDEWEB)

Song, Kee Nam; Song, K. N.; Yoon, K. H. (and others)

2007-03-15

A spacer grid in a LWR fuel assembly is a key structural component to support fuel rods and to enhance the heat transfer from the fuel rod to the coolant. In this research, the main research items are the development of inherent and high performance spacer grid shapes, the establishment of mechanical/structural analysis and test technology, and the set-up of basic test facilities for the spacer grid. The main research areas and results are as follows. 1. 18 different spacer grid candidates have been invented and applied for domestic and US patents. Among the candidates 16 are chosen from the patent. 2. Two kinds of spacer grids are finally selected for the advanced LWR fuel after detailed performance tests on the candidates and commercial spacer grids from a mechanical/structural point of view. According to the test results the features of the selected spacer grids are better than those of the commercial spacer grids. 3. Four kinds of basic test facilities are set up and the relevant test technologies are established. 4. Mechanical/structural analysis models and technology for spacer grid performance are developed and the analysis results are compared with the test results to enhance the reliability of the models.

Grid cut-off-effect

International Nuclear Information System (INIS)

Fischer, U.; Vosshenrich, R.; Grabbe, E.

1992-01-01

Tilting of a grid during portable radiography leads to uneven exposures, and errors greater than 3 0 can lead to errors in interpretation. Differentiation from abnormal findings can be made by recognising exposure difference of extrathoracic comparable areas. The difficulties caused by tilting of the grid can be reduced by increasing the film focus distance and by using suitable grids. A new cassette holder with an integrated balance makes it possible to correct tilting of the grid rapidly and effectively. This results in improved image quality which can be applied not only to conventional exposure systems but is also of advantage when using digital methods. (orig.) [de

Synergisms between smart metering and smart grid; Synergien zwischen Smart Metering und Smart Grid

Energy Technology Data Exchange (ETDEWEB)

Maas, Peter [IDS GmbH, Ettlingen (Germany)

2010-04-15

With the implementation of a smart metering solution, it is not only possible to acquire consumption data for billing but also to acquire relevant data of the distribution grid for grid operation. There is still a wide gap between the actual condition and the target condition. Synergies result from the use of a common infrastructure which takes account both of the requirements of smart metering and of grid operation. An open architecture also enables the future integration of further applications of the fields of smart grid and smart home. (orig.)

Power Quality of Grid-Connected Wind Turbines with DFIG and Their Interaction with the Grid

DEFF Research Database (Denmark)

Sun, Tao

quality issues of grid-connected wind turbines and the interaction between wind turbines and the grid. The specific goal of the research has been to investigate flicker emission and mitigation of grid-connected wind turbines with doubly fed induction generators (DFIG) during continuous operation...... measures are proposed to mitigate the flicker levels produced by grid-connected wind turbines with DFIG, respectively by wind turbine output reactive power control and using STATCOM. Simulation results demonstrate that these two measures are effective for flicker mitigation regardless of mean wind speed....... To evaluate the flicker levels produced by grid-connected wind turbines with DFIG, a flickermeter model is developed according to the IEC standard IEC 61000-4-15, which simulates the response of the lamp-eye-brain chain and provides on-line statistical analysis ofthe flicker signal and the final results...

Grid3: An Application Grid Laboratory for Science

CERN Multimedia

CERN. Geneva

2004-01-01

level services required by the participating experiments. The deployed infrastructure has been operating since November 2003 with 27 sites, a peak of 2800 processors, work loads from 10 different applications exceeding 1300 simultaneous jobs, and data transfers among sites of greater than 2 TB/day. The Grid3 infrastructure was deployed from grid level services provided by groups and applications within the collaboration. The services were organized into four distinct "grid level services" including: Grid3 Packaging, Monitoring and Information systems, User Authentication and the iGOC Grid Operatio...

Decentral Smart Grid Control

Science.gov (United States)

Schäfer, Benjamin; Matthiae, Moritz; Timme, Marc; Witthaut, Dirk

2015-01-01

Stable operation of complex flow and transportation networks requires balanced supply and demand. For the operation of electric power grids—due to their increasing fraction of renewable energy sources—a pressing challenge is to fit the fluctuations in decentralized supply to the distributed and temporally varying demands. To achieve this goal, common smart grid concepts suggest to collect consumer demand data, centrally evaluate them given current supply and send price information back to customers for them to decide about usage. Besides restrictions regarding cyber security, privacy protection and large required investments, it remains unclear how such central smart grid options guarantee overall stability. Here we propose a Decentral Smart Grid Control, where the price is directly linked to the local grid frequency at each customer. The grid frequency provides all necessary information about the current power balance such that it is sufficient to match supply and demand without the need for a centralized IT infrastructure. We analyze the performance and the dynamical stability of the power grid with such a control system. Our results suggest that the proposed Decentral Smart Grid Control is feasible independent of effective measurement delays, if frequencies are averaged over sufficiently large time intervals.

Decentral Smart Grid Control

International Nuclear Information System (INIS)

Schäfer, Benjamin; Matthiae, Moritz; Timme, Marc; Witthaut, Dirk

2015-01-01

Stable operation of complex flow and transportation networks requires balanced supply and demand. For the operation of electric power grids—due to their increasing fraction of renewable energy sources—a pressing challenge is to fit the fluctuations in decentralized supply to the distributed and temporally varying demands. To achieve this goal, common smart grid concepts suggest to collect consumer demand data, centrally evaluate them given current supply and send price information back to customers for them to decide about usage. Besides restrictions regarding cyber security, privacy protection and large required investments, it remains unclear how such central smart grid options guarantee overall stability. Here we propose a Decentral Smart Grid Control, where the price is directly linked to the local grid frequency at each customer. The grid frequency provides all necessary information about the current power balance such that it is sufficient to match supply and demand without the need for a centralized IT infrastructure. We analyze the performance and the dynamical stability of the power grid with such a control system. Our results suggest that the proposed Decentral Smart Grid Control is feasible independent of effective measurement delays, if frequencies are averaged over sufficiently large time intervals. (paper)

Grid-connected to/from off-grid transference for micro-grid inverters

OpenAIRE

Heredero Peris, Daniel; Chillón Antón, Cristian; Pages Gimenez, Marc; Gross, Gabriel Igor; Montesinos Miracle, Daniel

2013-01-01

This paper compares two methods for controlling the on-line transference from connected to stand-alone mode and vice versa in converters for micro-grids. The first proposes a method where the converter changes from CSI (Current Source Inverter) in grid-connected mode to VSI (Voltage Source Inverter) in off-grid. In the second method, the inverter always works as a non-ideal voltage source, acting as VSI, using AC droop control strategy.

The GridSite Web/Grid security system

International Nuclear Information System (INIS)

McNab, Andrew; Li Yibiao

2010-01-01

We present an overview of the current status of the GridSite toolkit, describing the security model for interactive and programmatic uses introduced in the last year. We discuss our experiences of implementing these internal changes and how they and previous rounds of improvements have been prompted by requirements from users and wider security trends in Grids (such as CSRF). Finally, we explain how these have improved the user experience of GridSite-based websites, and wider implications for portals and similar web/grid sites.

GRS - Guarantee of results for grid-connected solar photovoltaic systems; GRS - Garantierte Resultate von Solarstromanlagen

Energy Technology Data Exchange (ETDEWEB)

Meier, Ch.; Frei, R.

2001-07-01

This final report for the Swiss Federal Office of Energy describes the development of a performance guarantee for the power delivered by grid-connected photovoltaic (PV) power plant. This is important for investors, who need to be able to calculate the price of the energy produced by the PV plant. The report examines the results of various case studies and experience gained with GRS contracts developed in different countries including Switzerland, the Netherlands, France and Germany. The problems encountered, which provided feedback for the further development of the contract presented in the report, are discussed. The model contract, which proposes a framework which provides many possible variations and adaptations, is presented in detail. Various problem areas such as guaranteed energy yield, meteorological references, correction methods, failure detection, dispute settlement and many other points are covered.

Current Grid operation and future role of the Grid

Science.gov (United States)

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

Current Grid operation and future role of the Grid

International Nuclear Information System (INIS)

Smirnova, O

2012-01-01

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

A Novel Energy Efficient Topology Control Scheme Based on a Coverage-Preserving and Sleep Scheduling Model for Sensor Networks

Science.gov (United States)

Shi, Binbin; Wei, Wei; Wang, Yihuai; Shu, Wanneng

2016-01-01

In high-density sensor networks, scheduling some sensor nodes to be in the sleep mode while other sensor nodes remain active for monitoring or forwarding packets is an effective control scheme to conserve energy. In this paper, a Coverage-Preserving Control Scheduling Scheme (CPCSS) based on a cloud model and redundancy degree in sensor networks is proposed. Firstly, the normal cloud model is adopted for calculating the similarity degree between the sensor nodes in terms of their historical data, and then all nodes in each grid of the target area can be classified into several categories. Secondly, the redundancy degree of a node is calculated according to its sensing area being covered by the neighboring sensors. Finally, a centralized approximation algorithm based on the partition of the target area is designed to obtain the approximate minimum set of nodes, which can retain the sufficient coverage of the target region and ensure the connectivity of the network at the same time. The simulation results show that the proposed CPCSS can balance the energy consumption and optimize the coverage performance of the sensor network. PMID:27754405

A Novel Energy Efficient Topology Control Scheme Based on a Coverage-Preserving and Sleep Scheduling Model for Sensor Networks

Directory of Open Access Journals (Sweden)

Binbin Shi

2016-10-01

Full Text Available In high-density sensor networks, scheduling some sensor nodes to be in the sleep mode while other sensor nodes remain active for monitoring or forwarding packets is an effective control scheme to conserve energy. In this paper, a Coverage-Preserving Control Scheduling Scheme (CPCSS based on a cloud model and redundancy degree in sensor networks is proposed. Firstly, the normal cloud model is adopted for calculating the similarity degree between the sensor nodes in terms of their historical data, and then all nodes in each grid of the target area can be classified into several categories. Secondly, the redundancy degree of a node is calculated according to its sensing area being covered by the neighboring sensors. Finally, a centralized approximation algorithm based on the partition of the target area is designed to obtain the approximate minimum set of nodes, which can retain the sufficient coverage of the target region and ensure the connectivity of the network at the same time. The simulation results show that the proposed CPCSS can balance the energy consumption and optimize the coverage performance of the sensor network.

Smart Solar Grid. Integration of high penetration of photovoltaic in municipal low voltage distribution grids; Smart Solar Grid. Integration hoher Anteile von Photovoltaik in kommunalen Niederspannungsverteilnetzen

Energy Technology Data Exchange (ETDEWEB)

Ruf, Holger; Heilscher, Gerd [Hochschule Ulm (Germany); Meier, Florian [SWU Netze GmbH, Ulm (Germany)

2012-07-01

The high rate of decentralized generation in low voltage grids especially photovoltaic (PV) put the distribution grid operators to new challenges. Grid operation and grid planning have to respect the volatility and dynamic of decentralized generation now and in the future and adapt their previous proceedings. In the frame of the project Smart Solar Grid was a test site defined in the grid area of the DSO Stadtwerke Ulm/Neu-Ulm GmbH (SWU) to analyze the impact of the PV rise and possible solutions for the grid planning in the future. The first analysis based upon secondly measurements of the first test site. From this were statistical evaluation of the load flows and power variations done. Furthermore were the roof potential analysis results of the test site validated. These data are the base for the development of a forecast system for grid condition parameter. (orig.)

Switching overvoltages in offshore wind power grids

DEFF Research Database (Denmark)

Arana Aristi, Ivan

and cables are presented. In Chapter 4 results from time domain measurements and simulations of switching operations in offshore wind power grids are described. Specifically, switching operations on a single wind turbine, the collection grid, the export system and the external grid measured in several real...... offshore wind farms are shown together with simulation results. Switching operations in offshore wind power grids can be simulated with different electromagnetic transient programs. Different programs were used in the project and compared results are included in Chapter 4. Also in Chapter 4 different......Switching transients in wind turbines, the collection grid, the export system and the external grid in offshore wind farms, during normal or abnormal operation, are the most important phenomena when conducting insulation coordination studies. However, the recommended models and methods from...

Building the US National Fusion Grid: results from the National Fusion Collaboratory Project

International Nuclear Information System (INIS)

Schissel, D.P.; Burruss, J.R.; Finkelstein, A.; Flanagan, S.M.; Foster, I.T.; Fredian, T.W.; Greenwald, M.J.; Johnson, C.R.; Keahey, K.; Klasky, S.A.; Li, K.; McCune, D.C.; Papka, M.; Peng, Q.; Randerson, L.; Sanderson, A.; Stillerman, J.; Stevens, R.; Thompson, M.R.; Wallace, G.

2004-01-01

The US National Fusion Collaboratory Project is developing a persistent infrastructure to enable scientific collaboration for all aspects of magnetic fusion research. The project is creating a robust, user-friendly collaborative software environment and making it available to more than 1000 fusion scientists in 40 institutions who perform magnetic fusion research in the United States. In particular, the project is developing and deploying a national Fusion Energy Sciences Grid (FusionGrid) that is a system for secure sharing of computation, visualization, and data resources over the Internet. The FusionGrid goal is to allow scientists at remote sites to fully participate in experimental and computational activities as if they were working at a common site thereby creating a virtual organization of the US fusion community. The project is funded by the USDOE Office of Science, Scientific Discovery through Advanced Computing (SciDAC) Program and unites fusion and computer science researchers to directly address these challenges

Impact of Considering 110 kV Grid Structures on the Congestion Management in the German Transmission Grid

Science.gov (United States)

Hoffrichter, André; Barrios, Hans; Massmann, Janek; Venkataramanachar, Bhavasagar; Schnettler, Armin

2018-02-01

The structural changes in the European energy system lead to an increase of renewable energy sources that are primarily connected to the distribution grid. Hence the stationary analysis of the transmission grid and the regionalization of generation capacities are strongly influenced by subordinate grid structures. To quantify the impact on the congestion management in the German transmission grid, a 110 kV grid model is derived using publicly available data delivered by Open Street Map and integrated into an existing model of the European transmission grid. Power flow and redispatch simulations are performed for three different regionalization methods and grid configurations. The results show a significant impact of the 110 kV system and prove an overestimation of power flows in the transmission grid when neglecting subordinate grids. Thus, the redispatch volume in Germany to dissolve bottlenecks in case of N-1 contingencies decreases by 38 % when considering the 110 kV grid.

Electric grid in Spain: a private network of optical fiber with national coverage; Red electrica de Espana: una red privada de fibra optica con cobertura nacional

Energy Technology Data Exchange (ETDEWEB)

Gonzalez, A.

1995-12-31

Red Electrica constructed a grid with optical fiber in 1989 for the grids of 400-220 Kv. In 1995 the length of the grid will be of 6.600 Km. This grid supplies the telecommunication advanced services and contributes in the efficiency and quality of different tasks of Red Electrica.

Cooperative Cloud Service Aware Mobile Internet Coverage Connectivity Guarantee Protocol Based on Sensor Opportunistic Coverage Mechanism

Directory of Open Access Journals (Sweden)

Qin Qin

2015-01-01

Full Text Available In order to improve the Internet coverage ratio and provide connectivity guarantee, based on sensor opportunistic coverage mechanism and cooperative cloud service, we proposed the coverage connectivity guarantee protocol for mobile Internet. In this scheme, based on the opportunistic covering rules, the network coverage algorithm of high reliability and real-time security was achieved by using the opportunity of sensor nodes and the Internet mobile node. Then, the cloud service business support platform is created based on the Internet application service management capabilities and wireless sensor network communication service capabilities, which is the architecture of the cloud support layer. The cooperative cloud service aware model was proposed. Finally, we proposed the mobile Internet coverage connectivity guarantee protocol. The results of experiments demonstrate that the proposed algorithm has excellent performance, in terms of the security of the Internet and the stability, as well as coverage connectivity ability.

caGrid 1.0: a Grid enterprise architecture for cancer research.

Science.gov (United States)

Oster, Scott; Langella, Stephen; Hastings, Shannon; Ervin, David; Madduri, Ravi; Kurc, Tahsin; Siebenlist, Frank; Covitz, Peter; Shanbhag, Krishnakant; Foster, Ian; Saltz, Joel

2007-10-11

caGrid is the core Grid architecture of the NCI-sponsored cancer Biomedical Informatics Grid (caBIG) program. The current release, caGrid version 1.0, is developed as the production Grid software infrastructure of caBIG. Based on feedback from adopters of the previous version (caGrid 0.5), it has been significantly enhanced with new features and improvements to existing components. This paper presents an overview of caGrid 1.0, its main components, and enhancements over caGrid 0.5.

The North Seas Countries' Offshore Grid Initiative. Initial Findings. Final Report. Working Group 1 - Grid Configuration

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-11-15

This report focuses on the tasks and results from Working Group 1 (WG1), grid configuration and integration, chaired jointly by representatives from Denmark and the Netherlands. The methodology, assumptions concerning generation portfolio, load situation, available technology and results are presented. This report presents the WG1 Offshore Grid Study that supports the North Seas Countries' Offshore Grid Initiative (NSCOGI) final report. The information contained in this report aims to evaluate the long-term development of an offshore grid structure in the North Seas by providing a view on how such a grid may possibly develop in the future, based on the assumptions made for this study. The report aims to compare and evaluate the possible advantages and disadvantages of the long term development of an optimised, integrated (or meshed) offshore grid in the North Seas by providing a view of how that possible grid might develop in the future against changes to the electricity energy requirements. To evaluate basic variants, different transmission design topologies (radial and meshed) were compared and analysed with respect to various aspects, such as cost/benefits, import and export levels and the systems' CO2 emissions.

Advanced KSNP fuel, plus7 : grid-to-rod fretting wear resistance of the plus7 spacer grids

International Nuclear Information System (INIS)

Kim, Kyu Tae; Kim, Yong Hwan; Jang, Young Ki; Choi, Joon Hyung

2003-01-01

Vibration-induced grid-to-rod fretting wear initiates at a certain critical gap correlated with a critical work rate. A critical gap between grid and rod forms due to in-reactor performance of fuel, thermal relaxation of grid spring and irradiation growth of grid strap, etc. A critical work rate may be generated by three vibration mechanisms proposed in this paper. Three vibration mechanisms have been derived with various fretting wear experience in commercial reactors as well as various out-of-pile hydraulic test results. The first active vibration mechanism is high turbulence-induced excessive fuel rod vibration with the combination of excessive grid-to-rod gap. The second active vibration mechanism is self-excited fuel assembly vibration in a low frequency range caused by hydraulically unbalanced mixing vanes of the spacer grid assembly. The third active vibration mechanism is self-excited spacer grid strap vibration in quite a high frequency range caused by some spacer grid designs. In this study, each vibration mechanism on the grid-to-rod fretting wear damage is discussed. On the other hand, the effects of various grid designs on the fretting wear damage in the commercial reactors are predicted using the long-term fretting wear test results. It is found that the larger grid-to-rod initial contact area generates the less fretting wear damage. Consequently the conformal spring of PLUS7 is superior to typical convex shaped spring with regard to fretting wear resistance since the former generates relatively larger contact area than the latter

Flexible Control Strategy for Grid-Connected Inverter under Unbalanced Grid Faults without PLL

DEFF Research Database (Denmark)

Guo, Xiaoqiang; Liu, W.; Zhang, X.

2015-01-01

Power oscillation and current quality are the important performance targets for the grid-connected inverter under unbalanced grid faults. Firstly, the inherent reason for the current harmonic and power oscillation of the inverter is discussed with a quantitative analysis. Secondly, a new control...... strategy is proposed to achieve the coordinate control of power and current quality without the need for a phase-locked loop or voltage/current positive/negative sequence extraction calculation. Finally, the experimental tests are conducted under unbalanced grid faults, and the results verify...

MrGrid: a portable grid based molecular replacement pipeline.

Directory of Open Access Journals (Sweden)

Jason W Schmidberger

Full Text Available BACKGROUND: The crystallographic determination of protein structures can be computationally demanding and for difficult cases can benefit from user-friendly interfaces to high-performance computing resources. Molecular replacement (MR is a popular protein crystallographic technique that exploits the structural similarity between proteins that share some sequence similarity. But the need to trial permutations of search models, space group symmetries and other parameters makes MR time- and labour-intensive. However, MR calculations are embarrassingly parallel and thus ideally suited to distributed computing. In order to address this problem we have developed MrGrid, web-based software that allows multiple MR calculations to be executed across a grid of networked computers, allowing high-throughput MR. METHODOLOGY/PRINCIPAL FINDINGS: MrGrid is a portable web based application written in Java/JSP and Ruby, and taking advantage of Apple Xgrid technology. Designed to interface with a user defined Xgrid resource the package manages the distribution of multiple MR runs to the available nodes on the Xgrid. We evaluated MrGrid using 10 different protein test cases on a network of 13 computers, and achieved an average speed up factor of 5.69. CONCLUSIONS: MrGrid enables the user to retrieve and manage the results of tens to hundreds of MR calculations quickly and via a single web interface, as well as broadening the range of strategies that can be attempted. This high-throughput approach allows parameter sweeps to be performed in parallel, improving the chances of MR success.

Analyzing Resiliency of the Smart Grid Communication Architectures

Energy Technology Data Exchange (ETDEWEB)

None, None

2016-08-01

Smart grids are susceptible to cyber-attack as a result of new communication, control and computation techniques employed in the grid. In this paper, we characterize and analyze the resiliency of smart grid communication architecture, specifically an RF mesh based architecture, under cyber attacks. We analyze the resiliency of the communication architecture by studying the performance of high-level smart grid functions such as metering, and demand response which depend on communication. Disrupting the operation of these functions impacts the operational resiliency of the smart grid. Our analysis shows that it takes an attacker only a small fraction of meters to compromise the communication resiliency of the smart grid. We discuss the implications of our result to critical smart grid functions and to the overall security of the smart grid.

Medicare Coverage Database

Data.gov (United States)

U.S. Department of Health & Human Services — The Medicare Coverage Database (MCD) contains all National Coverage Determinations (NCDs) and Local Coverage Determinations (LCDs), local articles, and proposed NCD...

Gridded Species Distribution, Version 1: Global Amphibians Presence Grids

Data.gov (United States)

National Aeronautics and Space Administration — The Global Amphibians Presence Grids of the Gridded Species Distribution, Version 1 is a reclassified version of the original grids of amphibian species distribution...

Wind and Solar on the Power Grid: Myths and Misperceptions, Greening the Grid (Spanish Version)

Energy Technology Data Exchange (ETDEWEB)

Authors: Denholm, Paul; Cochran, Jaquelin; Brancucci Martinez-Anido, Carlo

2016-04-01

This is the Spanish version of the 'Greening the Grid - Wind and Solar on the Power Grid: Myths and Misperceptions'. Wind and solar are inherently more variable and uncertain than the traditional dispatchable thermal and hydro generators that have historically provided a majority of grid-supplied electricity. The unique characteristics of variable renewable energy (VRE) resources have resulted in many misperceptions regarding their contribution to a low-cost and reliable power grid. Common areas of concern include: 1) The potential need for increased operating reserves, 2) The impact of variability and uncertainty on operating costs and pollutant emissions of thermal plants, and 3) The technical limits of VRE penetration rates to maintain grid stability and reliability. This fact sheet corrects misperceptions in these areas.

A comparative analysis of dynamic grids vs. virtual grids using the A3pviGrid framework.

Science.gov (United States)

Shankaranarayanan, Avinas; Amaldas, Christine

2010-11-01

With the proliferation of Quad/Multi-core micro-processors in mainstream platforms such as desktops and workstations; a large number of unused CPU cycles can be utilized for running virtual machines (VMs) as dynamic nodes in distributed environments. Grid services and its service oriented business broker now termed cloud computing could deploy image based virtualization platforms enabling agent based resource management and dynamic fault management. In this paper we present an efficient way of utilizing heterogeneous virtual machines on idle desktops as an environment for consumption of high performance grid services. Spurious and exponential increases in the size of the datasets are constant concerns in medical and pharmaceutical industries due to the constant discovery and publication of large sequence databases. Traditional algorithms are not modeled at handing large data sizes under sudden and dynamic changes in the execution environment as previously discussed. This research was undertaken to compare our previous results with running the same test dataset with that of a virtual Grid platform using virtual machines (Virtualization). The implemented architecture, A3pviGrid utilizes game theoretic optimization and agent based team formation (Coalition) algorithms to improve upon scalability with respect to team formation. Due to the dynamic nature of distributed systems (as discussed in our previous work) all interactions were made local within a team transparently. This paper is a proof of concept of an experimental mini-Grid test-bed compared to running the platform on local virtual machines on a local test cluster. This was done to give every agent its own execution platform enabling anonymity and better control of the dynamic environmental parameters. We also analyze performance and scalability of Blast in a multiple virtual node setup and present our findings. This paper is an extension of our previous research on improving the BLAST application framework

Grid: From EGEE to EGI and from INFN-Grid to IGI

International Nuclear Information System (INIS)

Giselli, A.; Mazzuccato, M.

2009-01-01

In the last fifteen years the approach of the computational Grid has changed the way to use computing resources. Grid computing has raised interest worldwide in academia, industry, and government with fast development cycles. Great efforts, huge funding and resources have been made available through national, regional and international initiatives aiming at providing Grid infrastructures, Grid core technologies, Grid middle ware and Grid applications. The Grid software layers reflect the architecture of the services developed so far by the most important European and international projects. In this paper Grid e-Infrastructure story is given, detailing European, Italian and international projects such as EGEE, INFN-Grid and NAREGI. In addition the sustainability issue in the long-term perspective is described providing plans by European and Italian communities with EGI and IGI.

Feature combination analysis in smart grid based using SOM for Sudan national grid

Science.gov (United States)

Bohari, Z. H.; Yusof, M. A. M.; Jali, M. H.; Sulaima, M. F.; Nasir, M. N. M.

2015-12-01

In the investigation of power grid security, the cascading failure in multicontingency situations has been a test because of its topological unpredictability and computational expense. Both system investigations and burden positioning routines have their limits. In this project, in view of sorting toward Self Organizing Maps (SOM), incorporated methodology consolidating spatial feature (distance)-based grouping with electrical attributes (load) to evaluate the vulnerability and cascading impact of various part sets in the force lattice. Utilizing the grouping result from SOM, sets of overwhelming stacked beginning victimized people to perform assault conspires and asses the consequent falling impact of their failures, and this SOM-based approach viably distinguishes the more powerless sets of substations than those from the conventional burden positioning and other bunching strategies. The robustness of power grids is a central topic in the design of the so called "smart grid". In this paper, to analyze the measures of importance of the nodes in a power grid under cascading failure. With these efforts, we can distinguish the most vulnerable nodes and protect them, improving the safety of the power grid. Also we can measure if a structure is proper for power grids.

From the grid to the smart grid, topologically

Science.gov (United States)

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.

The North Seas Countries' Offshore Grid Initiative. Initial Findings. Final Report. Working Group 1 - Grid Configuration

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-11-15

This report focuses on the tasks and results from Working Group 1 (WG1), grid configuration and integration, chaired jointly by representatives from Denmark and the Netherlands. The methodology, assumptions concerning generation portfolio, load situation, available technology and results are presented. This report presents the WG1 Offshore Grid Study that supports the North Seas Countries' Offshore Grid Initiative (NSCOGI) final report. The information contained in this report aims to evaluate the long-term development of an offshore grid structure in the North Seas by providing a view on how such a grid may possibly develop in the future, based on the assumptions made for this study. The report aims to compare and evaluate the possible advantages and disadvantages of the long term development of an optimised, integrated (or meshed) offshore grid in the North Seas by providing a view of how that possible grid might develop in the future against changes to the electricity energy requirements. To evaluate basic variants, different transmission design topologies (radial and meshed) were compared and analysed with respect to various aspects, such as cost/benefits, import and export levels and the systems' CO2 emissions.

The Grid

CERN Document Server

Klotz, Wolf-Dieter

2005-01-01

Grid technology is widely emerging. Grid computing, most simply stated, is distributed computing taken to the next evolutionary level. The goal is to create the illusion of a simple, robust yet large and powerful self managing virtual computer out of a large collection of connected heterogeneous systems sharing various combinations of resources. This talk will give a short history how, out of lessons learned from the Internet, the vision of Grids was born. Then the extensible anatomy of a Grid architecture will be discussed. The talk will end by presenting a selection of major Grid projects in Europe and US and if time permits a short on-line demonstration.

Triple-layer smart grid business model

DEFF Research Database (Denmark)

Ma, Zheng; Lundgaard, Morten; Jørgensen, Bo Nørregaard

2016-01-01

Viewing the smart grid with the theory of business models may open opportunities in understanding and capturing values in new markets. This study tries to discover and map the smart grid ecosystem-based business model framework with two different environments (sub-Saharan Africa and Denmark......), and identifies the parameters for the smart grid solutions to the emerging markets. This study develops a triple-layer business model including the organizational (Niche), environmental (Intermediate), and global (Dominators) factors. The result uncovers an interface of market factors and stakeholders...... in a generic smart grid constellation. The findings contribute the transferability potential of the smart grid solutions between countries, and indicate the potential to export and import smart grid solutions based on the business modeling....

Parallel grid population

Science.gov (United States)

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.

Smart grids - French Expertise

International Nuclear Information System (INIS)

2015-11-01

The adaptation of electrical systems is the focus of major work worldwide. Bringing electricity to new territories, modernizing existing electricity grids, implementing energy efficiency policies and deploying renewable energies, developing new uses for electricity, introducing electric vehicles - these are the challenges facing a multitude of regions and countries. Smart Grids are the result of the convergence of electrical systems technologies with information and communications technologies. They play a key role in addressing the above challenges. Smart Grid development is a major priority for both public and private-sector actors in France. The experience of French companies has grown with the current French electricity system, a system that already shows extensive levels of 'intelligence', efficiency and competitiveness. French expertise also leverages substantial competence in terms of 'systems engineering', and can provide a tailored response to meet all sorts of needs. French products and services span all the technical and commercial building blocks that make up the Smart Grid value chain. They address the following issues: Improving the use and valuation of renewable energies and decentralized means of production, by optimizing the balance between generation and consumption. Strengthening the intelligence of the transmission and distribution grids: developing 'Supergrid', digitizing substations in transmission networks, and automating the distribution grids are the focus of a great many projects designed to reinforce the 'self-healing' capacity of the grid. Improving the valuation of decentralized flexibilities: this involves, among others, deploying smart meters, reinforcing active energy efficiency measures, and boosting consumers' contribution to grid balancing, via practices such as demand response which implies the aggregation of flexibility among residential, business, and/or industrial sites. Addressing current technological challenges, in

Preliminary results for validation of Computational Fluid Dynamics for prediction of flow through a split vane spacer grid

International Nuclear Information System (INIS)

Rashkovan, A.; Novog, D.R.

2012-01-01

This paper presents the results of the CFD simulations of turbulent flow past spacer grid with mixing vanes. This study summarizes the first stage of the ongoing numerical blind exercise organized by OECD-NEA. McMaster University along with other participants plan to submit a numerical prediction of the detailed flow field and turbulence characteristics of the flow past 5x5 rod bundle with a spacer grid equipped with two types of mixing vanes. The results will be compared with blind experimental measurements performed in Korea. Due to the fact that a number of the modeling strategies are suggested in literature for such types of flows, we have performed a series of tests to assess the mesh requirements, flow steadiness, turbulence modeling and wall treatment effects. Results of these studies are reported in the present paper. (author)

Dental Care Coverage and Use: Modeling Limitations and Opportunities

Science.gov (United States)

Moeller, John F.; Chen, Haiyan

2014-01-01

Objectives. We examined why older US adults without dental care coverage and use would have lower use rates if offered coverage than do those who currently have coverage. Methods. We used data from the 2008 Health and Retirement Study to estimate a multinomial logistic model to analyze the influence of personal characteristics in the grouping of older US adults into those with and those without dental care coverage and dental care use. Results. Compared with persons with no coverage and no dental care use, users of dental care with coverage were more likely to be younger, female, wealthier, college graduates, married, in excellent or very good health, and not missing all their permanent teeth. Conclusions. Providing dental care coverage to uninsured older US adults without use will not necessarily result in use rates similar to those with prior coverage and use. We have offered a model using modifiable factors that may help policy planners facilitate programs to increase dental care coverage uptake and use. PMID:24328635

The MicroGrid: A Scientific Tool for Modeling Computational Grids

Directory of Open Access Journals (Sweden)

H.J. Song

2000-01-01

Full Text Available The complexity and dynamic nature of the Internet (and the emerging Computational Grid demand that middleware and applications adapt to the changes in configuration and availability of resources. However, to the best of our knowledge there are no simulation tools which support systematic exploration of dynamic Grid software (or Grid resource behavior. We describe our vision and initial efforts to build tools to meet these needs. Our MicroGrid simulation tools enable Globus applications to be run in arbitrary virtual grid resource environments, enabling broad experimentation. We describe the design of these tools, and their validation on micro-benchmarks, the NAS parallel benchmarks, and an entire Grid application. These validation experiments show that the MicroGrid can match actual experiments within a few percent (2% to 4%.

Probabilistic Learning by Rodent Grid Cells.

Science.gov (United States)

Cheung, Allen

2016-10-01

Mounting evidence shows mammalian brains are probabilistic computers, but the specific cells involved remain elusive. Parallel research suggests that grid cells of the mammalian hippocampal formation are fundamental to spatial cognition but their diverse response properties still defy explanation. No plausible model exists which explains stable grids in darkness for twenty minutes or longer, despite being one of the first results ever published on grid cells. Similarly, no current explanation can tie together grid fragmentation and grid rescaling, which show very different forms of flexibility in grid responses when the environment is varied. Other properties such as attractor dynamics and grid anisotropy seem to be at odds with one another unless additional properties are assumed such as a varying velocity gain. Modelling efforts have largely ignored the breadth of response patterns, while also failing to account for the disastrous effects of sensory noise during spatial learning and recall, especially in darkness. Here, published electrophysiological evidence from a range of experiments are reinterpreted using a novel probabilistic learning model, which shows that grid cell responses are accurately predicted by a probabilistic learning process. Diverse response properties of probabilistic grid cells are statistically indistinguishable from rat grid cells across key manipulations. A simple coherent set of probabilistic computations explains stable grid fields in darkness, partial grid rescaling in resized arenas, low-dimensional attractor grid cell dynamics, and grid fragmentation in hairpin mazes. The same computations also reconcile oscillatory dynamics at the single cell level with attractor dynamics at the cell ensemble level. Additionally, a clear functional role for boundary cells is proposed for spatial learning. These findings provide a parsimonious and unified explanation of grid cell function, and implicate grid cells as an accessible neuronal population

Models for the modern power grid

Science.gov (United States)

Nardelli, Pedro H. J.; Rubido, Nicolas; Wang, Chengwei; Baptista, Murilo S.; Pomalaza-Raez, Carlos; Cardieri, Paulo; Latva-aho, Matti

2014-10-01

This article reviews different kinds of models for the electric power grid that can be used to understand the modern power system, the smart grid. From the physical network to abstract energy markets, we identify in the literature different aspects that co-determine the spatio-temporal multilayer dynamics of power system. We start our review by showing how the generation, transmission and distribution characteristics of the traditional power grids are already subject to complex behaviour appearing as a result of the the interplay between dynamics of the nodes and topology, namely synchronisation and cascade effects. When dealing with smart grids, the system complexity increases even more: on top of the physical network of power lines and controllable sources of electricity, the modernisation brings information networks, renewable intermittent generation, market liberalisation, prosumers, among other aspects. In this case, we forecast a dynamical co-evolution of the smart grid and other kind of networked systems that cannot be understood isolated. This review compiles recent results that model electric power grids as complex systems, going beyond pure technological aspects. From this perspective, we then indicate possible ways to incorporate the diverse co-evolving systems into the smart grid model using, for example, network theory and multi-agent simulation.

Smart Grids. Innovators talking; Smart Grids. Innovators aan het woord

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-02-15

Qualitative studies have been conducted of the results of completed projects focused on energy innovation, spread over the seven themes of the top sector Energy: Energy saving in industry, Energy conservation in the built environment, Gas, Bio-energy, Smart grids, Offshore Wind, Solar PV. This provides insight into the follow-up activities and lessons of some EOS (Energy Research Subsidy) completed projects with the aim to inspire, connect and strengthen the TKIs (Topconsortia for Knowledge and Innovation) and individual companies and researchers working on energy innovation. This report concerns the research on Smart Grids [Dutch] Er is een kwalitatief onderzoek uitgevoerd naar de resultaten van afgeronde projecten gericht op energie-innovatie, verdeeld over de zeven thema's van de topsector Energie: Energiebesparing in de industrie; Energiebesparing in de gebouwde omgeving; Gas; Bio-energie; Smart grids; Wind op zee; Zon-pv. Daarmee wordt inzicht gegeven in de vervolgactiviteiten en lessen van een aantal afgesloten EOS-projecten (Energie Onderzoek Subsidie) met het oog op het inspireren, verbinden en versterken van de TKI's (Topconsortia voor Kennis en Innovatie) en individuele bedrijven en onderzoekers die werken aan energie-innovatie. Dit rapport betreft het onderzoek naar Smart Grids.

Smart Grids. Innovators talking; Smart Grids. Innovators aan het woord

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-02-15

Qualitative studies have been conducted of the results of completed projects focused on energy innovation, spread over the seven themes of the top sector Energy: Energy saving in industry, Energy conservation in the built environment, Gas, Bio-energy, Smart grids, Offshore Wind, Solar PV. This provides insight into the follow-up activities and lessons of some EOS (Energy Research Subsidy) completed projects with the aim to inspire, connect and strengthen the TKIs (Topconsortia for Knowledge and Innovation) and individual companies and researchers working on energy innovation. This report concerns the research on Smart Grids [Dutch] Er is een kwalitatief onderzoek uitgevoerd naar de resultaten van afgeronde projecten gericht op energie-innovatie, verdeeld over de zeven thema's van de topsector Energie: Energiebesparing in de industrie; Energiebesparing in de gebouwde omgeving; Gas; Bio-energie; Smart grids; Wind op zee; Zon-pv. Daarmee wordt inzicht gegeven in de vervolgactiviteiten en lessen van een aantal afgesloten EOS-projecten (Energie Onderzoek Subsidie) met het oog op het inspireren, verbinden en versterken van de TKI's (Topconsortia voor Kennis en Innovatie) en individuele bedrijven en onderzoekers die werken aan energie-innovatie. Dit rapport betreft het onderzoek naar Smart Grids.

Distribution Grid Integration of Photovoltaic Systems in Germany – Implications on Grid Planning and Grid Operation

International Nuclear Information System (INIS)

Stetz, Thomas

2017-01-01

Photovoltaic is the most dispersed renewable energy source in Germany, typically interconnected to low and medium voltage systems. In recent years, cost-intensive grid reinforcements had to be undertaken all across Germany’s distribution grids in order to increase their hosting capacity for these photovoltaic installations. This paper presents an overview on research results which show that photovoltaic itself can provide ancillary services to reduce its cost of interconnection. Especially the provision of reactive power turned out to be a technically effective and economically efficient method to increase a grid’s hosting capacity for photovoltaic capacity. Different reactive power control methods were investigated, revealing significant differences with regards to their grid operation implications. Business cases for residential-scale photovoltaic applications have shifted from feed-in-tariff based active power feed-in to self-consumption. However, increasing the photovoltaic self-consumption by additional battery-storage systems is still not economically reliable in Germany. (author)

Household Coverage of Fortified Staple Food Commodities in Rajasthan, India.

Directory of Open Access Journals (Sweden)

Grant J Aaron

Full Text Available A spatially representative statewide survey was conducted in Rajasthan, India to assess household coverage of atta wheat flour, edible oil, and salt. An even distribution of primary sampling units were selected based on their proximity to centroids on a hexagonal grid laid over the survey area. A sample of n = 18 households from each of m = 252 primary sampling units PSUs was taken. Demographic data on all members of these households were collected, and a broader dataset was collected about a single caregiver and a child in the first 2 years of life. Data were collected on demographic and socioeconomic status; education; housing conditions; recent infant and child mortality; water, sanitation, and hygiene practices; food security; child health; infant and young child feeding practices; maternal dietary diversity; coverage of fortified staples; and maternal and child anthropometry. Data were collected from 4,627 households and the same number of caregiver/child pairs. Atta wheat flour was widely consumed across the state (83%; however, only about 7% of the atta wheat flour was classified as fortifiable, and only about 6% was actually fortified (mostly inadequately. For oil, almost 90% of edible oil consumed by households in the survey was classified as fortifiable, but only about 24% was fortified. For salt, coverage was high, with almost 85% of households using fortified salt and 66% of households using adequately fortified salt. Iodized salt coverage was also high; however, rural and poor population groups were less likely to be reached by the intervention. Voluntary fortification of atta wheat flour and edible oil lacked sufficient industry consolidation to cover significant portions of the population. It is crucial that appropriate delivery channels are utilized to effectively deliver essential micronutrients to at-risk population groups. Government distribution systems are likely the best means to accomplish this goal.

Synchronization in single-phase grid-connected photovoltaic systems under grid faults

DEFF Research Database (Denmark)

Yang, Yongheng; Blaabjerg, Frede

2012-01-01

The highly increasing penetration of single-phase photovoltaic (PV) systems pushes the grid requirements related to the integration of PV power systems to be updated. These upcoming regulations are expected to direct the grid-connected renewable generators to support the grid operation and stabil......The highly increasing penetration of single-phase photovoltaic (PV) systems pushes the grid requirements related to the integration of PV power systems to be updated. These upcoming regulations are expected to direct the grid-connected renewable generators to support the grid operation...

Grid generation methods

CERN Document Server

Liseikin, Vladimir D

2010-01-01

This book is an introduction to structured and unstructured grid methods in scientific computing, addressing graduate students, scientists as well as practitioners. Basic local and integral grid quality measures are formulated and new approaches to mesh generation are reviewed. In addition to the content of the successful first edition, a more detailed and practice oriented description of monitor metrics in Beltrami and diffusion equations is given for generating adaptive numerical grids. Also, new techniques developed by the author are presented, in particular a technique based on the inverted form of Beltrami’s partial differential equations with respect to control metrics. This technique allows the generation of adaptive grids for a wide variety of computational physics problems, including grid clustering to given function values and gradients, grid alignment with given vector fields, and combinations thereof. Applications of geometric methods to the analysis of numerical grid behavior as well as grid ge...

Grid-cell-based crop water accounting for the famine early warning system

Science.gov (United States)

Verdin, James; Klaver, Robert

2002-06-01

Rainfall monitoring is a regular activity of food security analysts for sub-Saharan Africa due to the potentially disastrous impact of drought. Crop water accounting schemes are used to track rainfall timing and amounts relative to phenological requirements, to infer water limitation impacts on yield. Unfortunately, many rain gauge reports are available only after significant delays, and the gauge locations leave large gaps in coverage. As an alternative, a grid-cell-based formulation for the water requirement satisfaction index (WRSI) was tested for maize in Southern Africa. Grids of input variables were obtained from remote sensing estimates of rainfall, meteorological models, and digital soil maps. The spatial WRSI was computed for the 1996-97 and 1997-98 growing seasons. Maize yields were estimated by regression and compared with a limited number of reports from the field for the 1996-97 season in Zimbabwe. Agreement at a useful level (r = 0·80) was observed. This is comparable to results from traditional analysis with station data. The findings demonstrate the complementary role that remote sensing, modelling, and geospatial analysis can play in an era when field data collection in sub-Saharan Africa is suffering an unfortunate decline. Published in 2002 by John Wiley & Sons, Ltd.

Smart grid technologies in local electric grids

Science.gov (United States)

Lezhniuk, Petro D.; Pijarski, Paweł; Buslavets, Olga A.

2017-08-01

The research is devoted to the creation of favorable conditions for the integration of renewable sources of energy into electric grids, which were designed to be supplied from centralized generation at large electric power stations. Development of distributed generation in electric grids influences the conditions of their operation - conflict of interests arises. The possibility of optimal functioning of electric grids and renewable sources of energy, when complex criterion of the optimality is balance reliability of electric energy in local electric system and minimum losses of electric energy in it. Multilevel automated system for power flows control in electric grids by means of change of distributed generation of power is developed. Optimization of power flows is performed by local systems of automatic control of small hydropower stations and, if possible, solar power plants.

Parallel Sn Sweeps on Unstructured Grids: Algorithms for Prioritization, Grid Partitioning, and Cycle Detection

International Nuclear Information System (INIS)

Plimpton, Steven J.; Hendrickson, Bruce; Burns, Shawn P.; McLendon, William III; Rauchwerger, Lawrence

2005-01-01

The method of discrete ordinates is commonly used to solve the Boltzmann transport equation. The solution in each ordinate direction is most efficiently computed by sweeping the radiation flux across the computational grid. For unstructured grids this poses many challenges, particularly when implemented on distributed-memory parallel machines where the grid geometry is spread across processors. We present several algorithms relevant to this approach: (a) an asynchronous message-passing algorithm that performs sweeps simultaneously in multiple ordinate directions, (b) a simple geometric heuristic to prioritize the computational tasks that a processor works on, (c) a partitioning algorithm that creates columnar-style decompositions for unstructured grids, and (d) an algorithm for detecting and eliminating cycles that sometimes exist in unstructured grids and can prevent sweeps from successfully completing. Algorithms (a) and (d) are fully parallel; algorithms (b) and (c) can be used in conjunction with (a) to achieve higher parallel efficiencies. We describe our message-passing implementations of these algorithms within a radiation transport package. Performance and scalability results are given for unstructured grids with up to 3 million elements (500 million unknowns) running on thousands of processors of Sandia National Laboratories' Intel Tflops machine and DEC-Alpha CPlant cluster

Greening the Grid - Advancing Solar, Wind, and Smart Grid Technologies (Spanish Version)

Energy Technology Data Exchange (ETDEWEB)

2016-04-01

This is the Spanish version of 'Greening the Grid - Advancing Solar, Wind, and Smart Grid Technologies'. 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.

The use and abuse of radiographic grids

International Nuclear Information System (INIS)

Brough, P.D.

1981-01-01

It is generally accepted that scattered radiation degrades the quality of the radiographic image. When this problem occurs, a radiographic grid may be applied which necessitates an increase in exposure. Investigations are reported in the following areas: reasons for the introduction of a radiographic grid; the ratio between kilovoltage and grid ratio; techniques resulting in higher contrast and resolution at low patient dose and the abuse of grids

Micro grids toward the smart grid

International Nuclear Information System (INIS)

Guerrero, J.

2011-01-01

Worldwide electrical grids are expecting to become smarter in the near future, with interest in Microgrids likely to grow. A microgrid can be defined as a part of the grid with elements of prime energy movers, power electronics converters, distributed energy storage systems and local loads, that can operate autonomously but also interacting with main grid. Thus, the ability of intelligent Microgrids to operate in island mode or connected to the grid will be a keypoint to cope with new functionalities and the integration of renewable energy resources. The functionalities expected for these small grids are: black start operation, frequency and voltage stability, active and reactive power flow control, active power filter capabilities, and storage energy management. In this presentation, a review of the main concepts related to flexible Microgrids will be introduced, with examples of real Microgrids. AC and DC Microgrids to integrate renewable and distributed energy resources will also be presented, as well as distributed energy storage systems, and standardization issues of these Microgrids. Finally, Microgrid hierarchical control will be analyzed looking at three different levels: i) a primary control based on the droop method, including an output impedance virtual loop; ii) a secondary control, which enables restoring any deviations produced by the primary control; and iii) a tertiary control to manage the power flow between the microgrid and the external electrical distribution system.

Smart grid security

CERN Document Server

Goel, Sanjay; Papakonstantinou, Vagelis; Kloza, Dariusz

2015-01-01

This book on smart grid security is meant for a broad audience from managers to technical experts. It highlights security challenges that are faced in the smart grid as we widely deploy it across the landscape. It starts with a brief overview of the smart grid and then discusses some of the reported attacks on the grid. It covers network threats, cyber physical threats, smart metering threats, as well as privacy issues in the smart grid. Along with the threats the book discusses the means to improve smart grid security and the standards that are emerging in the field. The second part of the b

Mapping of grid faults and grid codes

DEFF Research Database (Denmark)

Iov, F.; Hansen, Anca Daniela; Sørensen, Poul Ejnar

loads of wind turbines. The goal is also to clarify and define possible new directions in the certification process of power plant wind turbines, namely wind turbines, which participate actively in the stabilisation of power systems. Practical experience shows that there is a need...... challenges for the design of both the electrical system and the mechanical structure of wind turbines. An overview over the frequency of grid faults and the grid connection requirements in different relevant countries is done in this report. The most relevant study cases for the quantification of the loads......The present report is a part of the research project ''Grid fault and designbasis for wind turbine'' supported by Energinet.dk through the grant PSO F&U 6319. The objective of this project is to investigate into the consequences of the new grid connection requirements for the fatigue and extreme...

A Stationary Reference Frame Grid Synchronization System for Three-Phase Grid-Connected Power Converters Under Adverse Grid Conditions

DEFF Research Database (Denmark)

Rodríguez, P.; Luna, A.; Muñoz-Aguilar, R. S.

2012-01-01

synchronization method for three-phase three-wire networks, namely dual second-order generalized integrator (SOGI) frequency-locked loop. The method is based on two adaptive filters, implemented by using a SOGI on the stationary αβ reference frame, and it is able to perform an excellent estimation......Grid synchronization algorithms are of great importance in the control of grid-connected power converters, as fast and accurate detection of the grid voltage parameters is crucial in order to implement stable control strategies under generic grid conditions. This paper presents a new grid...

Vehicle-to-Grid Automatic Load Sharing with Driver Preference in Micro-Grids

Energy Technology Data Exchange (ETDEWEB)

Wang, Yubo; Nazaripouya, Hamidreza; Chu, Chi-Cheng; Gadh, Rajit; Pota, Hemanshu R.

2014-10-15

Integration of Electrical Vehicles (EVs) with power grid not only brings new challenges for load management, but also opportunities for distributed storage and generation. This paper comprehensively models and analyzes distributed Vehicle-to-Grid (V2G) for automatic load sharing with driver preference. In a micro-grid with limited communications, V2G EVs need to decide load sharing based on their own power and voltage profile. A droop based controller taking into account driver preference is proposed in this paper to address the distributed control of EVs. Simulations are designed for three fundamental V2G automatic load sharing scenarios that include all system dynamics of such applications. Simulation results demonstrate that active power sharing is achieved proportionally among V2G EVs with consideration of driver preference. In additional, the results also verify the system stability and reactive power sharing analysis in system modelling, which sheds light on large scale V2G automatic load sharing in more complicated cases.

Smart grids opportunities, developments, and trends

CERN Document Server

Ali, A B M Shawkat

2013-01-01

This book provides up to date knowledge, research results, and innovations in smart grids spanning design, implementation, analysis and evaluation of smart grid solutions to the challenging problems in all areas of the power industry.

GridICE: monitoring the user/application activities on the grid

International Nuclear Information System (INIS)

Aiftimiei, C; Pra, S D; Andreozzi, S; Fattibene, E; Misurelli, G; Cuscela, G; Donvito, G; Dudhalkar, V; Maggi, G; Pierro, A; Fantinel, S

2008-01-01

The monitoring of the grid user activity and application performance is extremely useful to plan resource usage strategies particularly in cases of complex applications. Large VOs, such as the LHC VOs, do their monitoring by means of dashboards. Other VOs or communities, like for example the BioinfoGRID one, are characterized by a greater diversification of the application types: so the effort to provide a dashboard like monitor is particularly heavy. The main theme of this paper is to show the improvements introduced in GridICE, a web tool built to provides an almost complete grid monitoring. These recent improvements allows GridICE to provide new reports on the resources usage with details of the VOMS groups, roles and users. By accessing the GridICE web pages, the grid user can get all information that is relevant to keep track of his activity on the grid. In the same way, the activity of a VOMS group can be distinguished from the activity of the entire VO. In this paper we briefly talk about the features and advantages of this approach and, after discussing the requirements, we describe the software solutions, middleware and prerequisite to manage and retrieve the user's credentials

Providing Universal Health Insurance Coverage in Nigeria.

Science.gov (United States)

Okebukola, Peter O; Brieger, William R

2016-07-07

Despite a stated goal of achieving universal coverage, the National Health Insurance Scheme of Nigeria had achieved only 4% coverage 12 years after it was launched. This study assessed the plans of the National Health Insurance Scheme to achieve universal health insurance coverage in Nigeria by 2015 and discusses the challenges facing the scheme in achieving insurance coverage. In-depth interviews from various levels of the health-care system in the country, including providers, were conducted. The results of the analysis suggest that challenges to extending coverage include the difficulty in convincing autonomous state governments to buy into the scheme and an inadequate health workforce that might not be able to meet increased demand. Recommendations for increasing the scheme's coverage include increasing decentralization and strengthening human resources for health in the service delivery systems. Strong political will is needed as a catalyst to achieving these goals. © The Author(s) 2016.

Mapping of grid faults and grid codes

DEFF Research Database (Denmark)

Iov, Florin; Hansen, A.D.; Sørensen, P.

loads of wind turbines. The goal is also to clarify and define possible new directions in the certification process of power plant wind turbines, namely wind turbines, which participate actively in the stabilisation of power systems. Practical experience shows that there is a need...... challenges for the design of both the electrical system and the mechanical structure of wind turbines. An overview over the frequency of grid faults and the grid connection requirements in different relevant countries is done in this report. The most relevant study cases for the quantification of the loads......The present report is a part of the research project "Grid fault and design basis for wind turbine" supported by Energinet.dk through the grant PSO F&U 6319. The objective of this project is to investigate into the consequences of the new grid connection requirements for the fatigue and extreme...

Computing Flows Using Chimera and Unstructured Grids

Science.gov (United States)

Liou, Meng-Sing; Zheng, Yao

2006-01-01

DRAGONFLOW is a computer program that solves the Navier-Stokes equations of flows in complexly shaped three-dimensional regions discretized by use of a direct replacement of arbitrary grid overlapping by nonstructured (DRAGON) grid. A DRAGON grid (see figure) is a combination of a chimera grid (a composite of structured subgrids) and a collection of unstructured subgrids. DRAGONFLOW incorporates modified versions of two prior Navier-Stokes-equation-solving programs: OVERFLOW, which is designed to solve on chimera grids; and USM3D, which is used to solve on unstructured grids. A master module controls the invocation of individual modules in the libraries. At each time step of a simulated flow, DRAGONFLOW is invoked on the chimera portion of the DRAGON grid in alternation with USM3D, which is invoked on the unstructured subgrids of the DRAGON grid. The USM3D and OVERFLOW modules then immediately exchange their solutions and other data. As a result, USM3D and OVERFLOW are coupled seamlessly.

Grid-Voltage-Feedforward Active Damping for Grid-Connected Inverter with LCL Filter

DEFF Research Database (Denmark)

Lu, Minghui; Wang, Xiongfei; Blaabjerg, Frede

2016-01-01

For the grid-connected voltage source inverters, the feedforward scheme of grid voltage is commonly adopted to mitigate the current distortion caused by grid background voltages harmonics. This paper investigates the grid-voltage-feedforward active damping for grid connected inverter with LCL...... filter. It reveals that proportional feedforward control can not only fulfill the mitigation of grid disturbance, but also offer damping effects on the LCL filter resonance. Digital delays are intrinsic to digital controlled inverters; with these delays, the feedforward control can be equivalent...

Coupling mechanism of electric vehicle and grid under the background of smart grid

Science.gov (United States)

Dong, Mingyu; Li, Dezhi; Chen, Rongjun; Shu, Han; He, Yongxiu

2018-02-01

With the development of smart distribution technology in the future, electric vehicle users can not only charge reasonably based on peak-valley price, they can also discharge electricity into the power grid to realize their economic benefit when it’s necessary and thus promote peak load shifting. According to the characteristic that future electric vehicles can discharge, this paper studies the interaction effect between electric vehicles and the grid based on TOU (time of use) Price Strategy. In this paper, four scenarios are used to compare the change of grid load after implementing TOU Price Strategy. The results show that the wide access of electric vehicles can effectively reduce peak and valley difference.

A roadmap for caGrid, an enterprise Grid architecture for biomedical research.

Science.gov (United States)

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.

Fiber-wireless for smart grid: A survey

Science.gov (United States)

Radzi, NAM; Ridwan, MA; Din, NM; Abdullah, F.; Mustafa, IS; l-Mansoori, MH

2017-11-01

Smart grid allows two-way communication between power utility companies and their customers while having the ability to sense along the transmission lines. However, the downside is such, when the smart devices are transmitting data simultaneously, it results in network congestion. Fiber wireless (FiWi) network is one of the best congestion solutions for smart grid up to date. In this paper, a survey of current literature on FiWi for smart grid will be reviewed and a testbed to test the protocols and algorithms for FiWi in smart grid will be proposed. The results of number of packets received and delay vs packet transmitted obtained via the testbed are compared with the results obtained via simulation and they show that they are in line with each other, validating the accuracy of the testbed.

Numerical study of a gridded E-GUN with a very small cathode-grid distance (150 {mu}m) using EGN2

Energy Technology Data Exchange (ETDEWEB)

Ronsivalle, C. [ENEA, Centro Ricerche Frascati, Rome (Italy). Dip. Innovazione

1997-01-01

A numerical study of a triode gun with a very small cathode-grid distance (150 {mu}m) which allows to evaluate with great accuracy the effect of the grid and of the temperature on the final beam emittance is presented. The simulation uses a modified version of the bidimensional code EGUN for PC that simulates the grid with a set of concentric rings and allows to define several regions of different mesh size, providing the way to connect results between adjacent regions. The calculation procedure is described in detail together with the results of the simulation for different values of the grid potential.

AQUAGRID: The subsurface hydrology Grid service of the Sardinian regional Grid infrastructure

International Nuclear Information System (INIS)

Lecca, G.; Murgia, F.; Maggi, P.; Perias, A.

2007-01-01

AQUAGRID is the subsurface hydrology service of the Sardinian regional Grid infrastructure, designed to deliver complex environmental applications via a user-friendly Web portal. The service is oriented towards the needs of water professionals providing them a flexible and powerful tool to solve water resources management problems and aid decision between different remediation options for contaminated soil and groundwater. In this paper, the AQUAGRID application concept and the enabling technologies are illustrated. The heart of the service is the CODESA-3D hydrogeological model to simulate complex and large groundwater flow and contaminant transport problems. The relevant experience gained from the porting of the CODESA-3D application on the EGEE infrastructure, via the GILDA test bed (https://gilda.ct.infn.it), has contributed to the service prototype. AQUAGRID is built on top of compute-Grid technologies by means of the EnginFrame Grid portal. The portal enables the interaction with the underlying Grid infrastructure and manages the computational requirements of the whole application system. Data management, distribution and visualization mechanisms are based on the tools provided by the DatacroSSing Decision Support System (http://datacrossing.crs4.it). The DSS, built on top of the SRB data-Grid middleware, is based on Web-GIS and relational database technologies. The resulting production environment allows the end-user to visualize and interact with the results of the performed analyses, using graphs, annotated maps and 3D objects. Such a set of graphical widgets increases enormously the number of AQUAGRID potential users because it does not require any specific expertise of the physical model and technological background to be understood. (Author)

Media Coverage of Nuclear Energy after Fukushima

International Nuclear Information System (INIS)

Oltra, C.; Roman, P.; Prades, A.

2013-01-01

This report presents the main findings of a content analysis of printed media coverage of nuclear energy in Spain before and after the Fukushima accident. Our main objective is to understand the changes in the presentation of nuclear fission and nuclear fusion as a result of the accident in Japan. We specifically analyze the volume of coverage and thematic content in the media coverage for nuclear fusion from a sample of Spanish print articles in more than 20 newspapers from 2008 to 2012. We also analyze the media coverage of nuclear energy (fission) in three main Spanish newspapers one year before and one year after the accident. The results illustrate how the media contributed to the presentation of nuclear power in the months before and after the accident. This could have implications for the public understanding of nuclear power. (Author)

Media Coverage of Nuclear Energy after Fukushima

Energy Technology Data Exchange (ETDEWEB)

Oltra, C.; Roman, P.; Prades, A.

2013-07-01

This report presents the main findings of a content analysis of printed media coverage of nuclear energy in Spain before and after the Fukushima accident. Our main objective is to understand the changes in the presentation of nuclear fission and nuclear fusion as a result of the accident in Japan. We specifically analyze the volume of coverage and thematic content in the media coverage for nuclear fusion from a sample of Spanish print articles in more than 20 newspapers from 2008 to 2012. We also analyze the media coverage of nuclear energy (fission) in three main Spanish newspapers one year before and one year after the accident. The results illustrate how the media contributed to the presentation of nuclear power in the months before and after the accident. This could have implications for the public understanding of nuclear power. (Author)

Grid computing in high-energy physics

International Nuclear Information System (INIS)

Bischof, R.; Kuhn, D.; Kneringer, E.

2003-01-01

Full text: The future high energy physics experiments are characterized by an enormous amount of data delivered by the large detectors presently under construction e.g. at the Large Hadron Collider and by a large number of scientists (several thousands) requiring simultaneous access to the resulting experimental data. Since it seems unrealistic to provide the necessary computing and storage resources at one single place, (e.g. CERN), the concept of grid computing i.e. the use of distributed resources, will be chosen. The DataGrid project (under the leadership of CERN) develops, based on the Globus toolkit, the software necessary for computation and analysis of shared large-scale databases in a grid structure. The high energy physics group Innsbruck participates with several resources in the DataGrid test bed. In this presentation our experience as grid users and resource provider is summarized. In cooperation with the local IT-center (ZID) we installed a flexible grid system which uses PCs (at the moment 162) in student's labs during nights, weekends and holidays, which is especially used to compare different systems (local resource managers, other grid software e.g. from the Nordugrid project) and to supply a test bed for the future Austrian Grid (AGrid). (author)

Grid Architecture 2

Energy Technology Data Exchange (ETDEWEB)

Taft, Jeffrey D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

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.

GridOrbit public display

DEFF Research Database (Denmark)

Ramos, Juan David Hincapie; Tabard, Aurélien; Bardram, Jakob

2010-01-01

We introduce GridOrbit, a public awareness display that visualizes the activity of a community grid used in a biology laboratory. This community grid executes bioin-formatics algorithms and relies on users to donate CPU cycles to the grid. The goal of GridOrbit is to create a shared awareness about...

Smart Grid: Network simulator for smart grid test-bed

International Nuclear Information System (INIS)

Lai, L C; Ong, H S; Che, Y X; Do, N Q; Ong, X J

2013-01-01

Smart Grid become more popular, a smaller scale of smart grid test-bed is set up at UNITEN to investigate the performance and to find out future enhancement of smart grid in Malaysia. The fundamental requirement in this project is design a network with low delay, no packet drop and with high data rate. Different type of traffic has its own characteristic and is suitable for different type of network and requirement. However no one understands the natural of traffic in smart grid. This paper presents the comparison between different types of traffic to find out the most suitable traffic for the optimal network performance.

Examples of grid generation with implicitly specified surfaces using GridPro (TM)/az3000. 1: Filleted multi-tube configurations

Science.gov (United States)

Cheng, Zheming; Eiseman, Peter R.

1995-01-01

With examples, we illustrate how implicitly specified surfaces can be used for grid generation with GridPro/az3000. The particular examples address two questions: (1) How do you model intersecting tubes with fillets? and (2) How do you generate grids inside the intersected tubes? The implication is much more general. With the results in a forthcoming paper which develops an easy-to-follow procedure for implicit surface modeling, we provide a powerful means for rapid prototyping in grid generation.

Grid Voltage Modulated Control of Grid-Connected Voltage Source Inverters under Unbalanced Grid Conditions

DEFF Research Database (Denmark)

Li, Mingshen; Gui, Yonghao; Quintero, Juan Carlos Vasquez

2017-01-01

In this paper, an improved grid voltage modulated control (GVM) with power compensation is proposed for grid-connected voltage inverters when the grid voltage is unbalanced. The objective of the proposed control is to remove the power ripple and to improve current quality. Three power compensation...... objectives are selected to eliminate the negative sequence components of currents. The modified GVM method is designed to obtain two separate second-order systems for not only the fast convergence rate of the instantaneous active and reactive powers but also the robust performance. In addition, this method...

Particle simulation of grid system for krypton ion thrusters

Directory of Open Access Journals (Sweden)

Maolin CHEN

2018-04-01

Full Text Available The transport processes of plasmas in grid systems of krypton (Kr ion thrusters at different acceleration voltages were simulated with a 3D-PIC model, and the result was compared with xenon (Xe ion thrusters. The variation of the screen grid transparency, the accelerator grid current ratio and the divergence loss were explored. It is found that the screen grid transparency increases with the acceleration voltage and decreases with the beam current, while the accelerator grid current ratio and divergence loss decrease first and then increase with the beam current. This result is the same with Xe ion thrusters. Simulation results also show that Kr ion thrusters have more advantages than Xe ion thrusters, such as higher screen grid transparency, smaller accelerator grid current ratio, larger cut-off current threshold, and better divergence loss characteristic. These advantages mean that Kr ion thrusters have the ability of operating in a wide range of current. Through comprehensive analyses, it can be concluded that using Kr as propellant is very suitable for a multi-mode ion thruster design. Keywords: Grid system, Ion thrusters, Krypton, Particle in cell method, Plasma

EASE-Grid 2.0: Incremental but Significant Improvements for Earth-Gridded Data Sets

Directory of Open Access Journals (Sweden)

Matthew H. Savoie

2012-03-01

Full Text Available Defined in the early 1990s for use with gridded satellite passive microwave data, the Equal-Area Scalable Earth Grid (EASE-Grid was quickly adopted and used for distribution of a variety of satellite and in situ data sets. Conceptually easy to understand, EASE-Grid suffers from limitations that make it impossible to format in the widely popular GeoTIFF convention without reprojection. Importing EASE-Grid data into standard mapping software packages is nontrivial and error-prone. This article defines a standard for an improved EASE-Grid 2.0 definition, addressing how the changes rectify issues with the original grid definition. Data distributed using the EASE-Grid 2.0 standard will be easier for users to import into standard software packages and will minimize common reprojection errors that users had encountered with the original EASE-Grid definition.

Smart Grid Integration Laboratory

Energy Technology Data Exchange (ETDEWEB)

Troxell, Wade [Colorado State Univ., Fort Collins, CO (United States)

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

Grid enablement of OpenGeospatial Web Services: the G-OWS Working Group

Science.gov (United States)

Mazzetti, Paolo

2010-05-01

In last decades two main paradigms for resource sharing emerged and reached maturity: the Web and the Grid. They both demonstrate suitable for building Distributed Computing Infrastructures (DCIs) supporting the coordinated sharing of resources (i.e. data, information, services, etc) on the Internet. Grid and Web DCIs have much in common as a result of their underlying Internet technology (protocols, models and specifications). However, being based on different requirements and architectural approaches, they show some differences as well. The Web's "major goal was to be a shared information space through which people and machines could communicate" [Berners-Lee 1996]. The success of the Web, and its consequent pervasiveness, made it appealing for building specialized systems like the Spatial Data Infrastructures (SDIs). In this systems the introduction of Web-based geo-information technologies enables specialized services for geospatial data sharing and processing. The Grid was born to achieve "flexible, secure, coordinated resource sharing among dynamic collections of individuals, institutions, and resources" [Foster 2001]. It specifically focuses on large-scale resource sharing, innovative applications, and, in some cases, high-performance orientation. In the Earth and Space Sciences (ESS) the most part of handled information is geo-referred (geo-information) since spatial and temporal meta-information is of primary importance in many application domains: Earth Sciences, Disasters Management, Environmental Sciences, etc. On the other hand, in several application areas there is the need of running complex models which require the large processing and storage capabilities that the Grids are able to provide. Therefore the integration of geo-information and Grid technologies might be a valuable approach in order to enable advanced ESS applications. Currently both geo-information and Grid technologies have reached a high level of maturity, allowing to build such an

Adult vaccination coverage levels among users of complementary/alternative medicine – results from the 2002 National Health Interview Survey (NHIS

Directory of Open Access Journals (Sweden)

Bardenheier Barbara H

2008-02-01

Full Text Available Abstract Background While many Complementary/Alternative Medicine (CAM practitioners do not object to immunization, some discourage or even actively oppose vaccination among their patients. However, previous studies in this area have focused on childhood immunizations, and it is unknown whether and to what extent CAM practitioners may influence the vaccination behavior of their adult patients. The purpose of this study was to describe vaccination coverage levels of adults aged ≥ 18 years according to their CAM use status and determine if there is an association between CAM use and adult vaccination coverage. Methods Data from the 2002 National Health Interview Survey, limited to 30,617 adults that provided at least one valid answer to the CAM supplement, were analyzed. Receipt of influenza vaccine during the past 12 months, pneumococcal vaccine (ever, and ≥ 1 dose of hepatitis B vaccine was self-reported. Coverage levels for each vaccine by CAM use status were determined for adults who were considered high priority for vaccination because of the presence of a high risk condition and for non-priority adults. Multivariable analyses were conducted to evaluate the association between CAM users and vaccination status, adjusting for demographic and healthcare utilization characteristics. Results Overall, 36% were recent CAM users. Among priority adults, adjusted vaccination coverage levels were significantly different between recent and non-CAM users for influenza (44% vs 38%; p-value Conclusion Vaccination coverage levels among recent CAM users were found to be higher than non-CAM users. Because CAM use has been increasing over time in the U.S., it is important to continue monitoring CAM use and its possible influence on receipt of immunizations among adults. Since adult vaccination coverage levels remain below Healthy People 2010 goals, it may be beneficial to work with CAM practitioners to promote adult vaccines as preventive services in

Grid pulser

International Nuclear Information System (INIS)

Jansweijer, P.P.M.; Es, J.T. van.

1990-01-01

This report describes a fast pulse generator. This generator delivers a high-voltage pulse of at most 6000 V with a rise time being smaller than 50 nS. this results in a slew rate of more than 120.000 volts per μS. The pulse generator is used to control the grid of the injector of the electron accelerator MEA. The capacity of this grid is about 60 pF. In order to charge this capacity up to 6000 volts in 50 nS a current of 8 ampere is needed. The maximal pulse length is 50 μS with a repeat frequency of 500 Hz. During this 50 μS the stability of the pulse amplitude is better than 0.1%. (author). 20 figs

Auction Mechanism of Micro-Grid Project Transfer

Directory of Open Access Journals (Sweden)

Yong Long

2017-10-01

Full Text Available Micro-grid project transfer is the primary issue of micro-grid development. The efficiency and quality of the micro-grid project transfer directly affect the quality of micro-grid project construction and development, which is very important for the sustainable development of micro-grid. This paper constructs a multi-attribute auction model of micro-grid project transfer, which reflects the characteristics of micro-grid system and the interests of stakeholders, calculates the optimal bidding strategy and analyzes the influence of relevant factors on auction equilibrium by multi-stage dynamic game with complete information, and makes a numerical simulation analysis. Results indicate that the optimal strategy of auction mechanism is positively related to power quality, energy storage quality, and carbon emissions. Different from the previous lowest price winning mechanism, the auction mechanism formed in this paper emphasizes that the energy suppliers which provide the comprehensive optimization of power quality, energy storage quality, carbon emissions, and price will win the auction, when both the project owners and energy suppliers maximize their benefits under this auction mechanism. The auction mechanism is effective because it is in line with the principle of individual rationality and incentive compatibility. In addition, the number of energy suppliers participating in the auction and the cost of the previous auction are positively related to the auction equilibrium, both of which are adjusting the equilibrium results of the auction. At the same time, the utilization rate of renewable energy and the comprehensive utilization of energy also have a positive impact on the auction equilibrium. In the end, this paper puts forward a series of policy suggestions about micro-grid project auction. The research in this paper is of great significance to improve the auction quality of micro-grid projects and promote the sustainable development of micro-grid.

Direct numerical simulation of turbulent mixing in grid-generated turbulence

International Nuclear Information System (INIS)

Nagata, Kouji; Suzuki, Hiroki; Sakai, Yasuhiko; Kubo, Takashi; Hayase, Toshiyuki

2008-01-01

Turbulent mixing of passive scalar (heat) in grid-generated turbulence (GGT) is simulated by means of direct numerical simulation (DNS). A turbulence-generating grid, on which the velocity components are set to zero, is located downstream of the channel entrance, and it is numerically constructed on the staggered mesh arrangement using the immersed boundary method. The grid types constructed are: (a) square-mesh biplane grid, (b) square-mesh single-plane grid, (c) composite grid consisting of parallel square-bars and (d) fractal grid. Two fluids with different temperatures are provided separately in the upper and lower streams upstream of the turbulence-generating grids, generating the thermal mixing layer behind the grids. For the grid (a), simulations for two different Prandtl numbers of 0.71 and 7.1, corresponding to air and water flows, are conducted to investigate the effect of the Prandtl number. The results show that the typical grid turbulence and shearless mixing layer are generated downstream of the grids. The results of the scalar field show that a typical thermal mixing layer is generated as well, and the effects of the Prandtl numbers on turbulent heat transfer are observed.

Direct numerical simulation of turbulent mixing in grid-generated turbulence

Energy Technology Data Exchange (ETDEWEB)

Nagata, Kouji; Suzuki, Hiroki; Sakai, Yasuhiko; Kubo, Takashi [Department of Mechanical Science and Engineering, Nagoya University, Nagoya 464-8603 (Japan); Hayase, Toshiyuki [Institute of Fluid Science, Tohoku University, Sendai 980-8577 (Japan)], E-mail: nagata@nagoya-u.jp, E-mail: hsuzuki@nagoya-u.jp, E-mail: ysakai@mech.nagoya-u.ac.jp, E-mail: t-kubo@nagoya-u.jp, E-mail: hayase@ifs.tohoku.ac.jp

2008-12-15

Turbulent mixing of passive scalar (heat) in grid-generated turbulence (GGT) is simulated by means of direct numerical simulation (DNS). A turbulence-generating grid, on which the velocity components are set to zero, is located downstream of the channel entrance, and it is numerically constructed on the staggered mesh arrangement using the immersed boundary method. The grid types constructed are: (a) square-mesh biplane grid, (b) square-mesh single-plane grid, (c) composite grid consisting of parallel square-bars and (d) fractal grid. Two fluids with different temperatures are provided separately in the upper and lower streams upstream of the turbulence-generating grids, generating the thermal mixing layer behind the grids. For the grid (a), simulations for two different Prandtl numbers of 0.71 and 7.1, corresponding to air and water flows, are conducted to investigate the effect of the Prandtl number. The results show that the typical grid turbulence and shearless mixing layer are generated downstream of the grids. The results of the scalar field show that a typical thermal mixing layer is generated as well, and the effects of the Prandtl numbers on turbulent heat transfer are observed.

Ion extraction capabilities of closely spaced grids

Science.gov (United States)

Rovang, D. C.; Wilbur, P. J.

1982-01-01

The ion extraction capabilities of accelerator systems with small screen hole diameters (less than 2.0 mm) are investigated at net-accelerating voltages of 100, 300, and 500 V. Results show that the impingement-limited perveance is not dramatically affected by reductions in screen hole diameter to 1.0 mm, but impingement-limited performance was found to be dependent on the grid separation distance, the discharge-to-total accelerating voltage ratio, and the net-to-total accelerating voltage ratio. Results obtained using small hole diameters and closely spaced grids indicate a new mode of grid operation where high current density operation can be achieved with a specified net acceleration voltage by operating the grids at a high rather than low net-to-total acceleration voltage. Beam current densities as high as 25 mA/sq cm were obtained using grids with 1.0 mm diameter holes operating at a net accelerating voltage of 500 V.

Computer Simulation of the UMER Gridded Gun

CERN Document Server

Haber, Irving; Friedman, Alex; Grote, D P; Kishek, Rami A; Reiser, Martin; Vay, Jean-Luc; Zou, Yun

2005-01-01

The electron source in the University of Maryland Electron Ring (UMER) injector employs a grid 0.15 mm from the cathode to control the current waveform. Under nominal operating conditions, the grid voltage during the current pulse is sufficiently positive relative to the cathode potential to form a virtual cathode downstream of the grid. Three-dimensional computer simulations have been performed that use the mesh refinement capability of the WARP particle-in-cell code to examine a small region near the beam center in order to illustrate some of the complexity that can result from such a gridded structure. These simulations have been found to reproduce the hollowed velocity space that is observed experimentally. The simulations also predict a complicated time-dependent response to the waveform applied to the grid during the current turn-on. This complex temporal behavior appears to result directly from the dynamics of the virtual cathode formation and may therefore be representative of the expected behavior in...

A pressure drop model for PWR grids

Energy Technology Data Exchange (ETDEWEB)

Oh, Dong Seok; In, Wang Ki; Bang, Je Geon; Jung, Youn Ho; Chun, Tae Hyun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1999-12-31

A pressure drop model for the PWR grids with and without mixing device is proposed at single phase based on the fluid mechanistic approach. Total pressure loss is expressed in additive way for form and frictional losses. The general friction factor correlations and form drag coefficients available in the open literatures are used to the model. As the results, the model shows better predictions than the existing ones for the non-mixing grids, and reasonable agreements with the available experimental data for mixing grids. Therefore it is concluded that the proposed model for pressure drop can provide sufficiently good approximation for grid optimization and design calculation in advanced grid development. 7 refs., 3 figs., 3 tabs. (Author)

Design optimization of grid-connected PV inverters

DEFF Research Database (Denmark)

Koutroulis, Eftichios; Blaabjerg, Frede

2011-01-01

The DC/AC inverters are the key elements in grid-connected PV energy production systems. In this paper, new design optimization techniques focused on transformerless (very high efficiency) PV inverters are proposed. They have been developed based on an analysis of the deficiencies of the current......, state-of-the-art PV inverters design technology, which limits the amount of PV energy supplied into the electric grid. The influences of the electric grid regulations and standards and the PV array operational characteristics on the design of grid-connected PV inverters have also been considered....... The simulation results verify that the proposed optimization techniques enable the maximization of the PV energy injected into the electric grid by the optimized PV installation....

A pressure drop model for PWR grids

Energy Technology Data Exchange (ETDEWEB)

Oh, Dong Seok; In, Wang Ki; Bang, Je Geon; Jung, Youn Ho; Chun, Tae Hyun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1998-12-31

A pressure drop model for the PWR grids with and without mixing device is proposed at single phase based on the fluid mechanistic approach. Total pressure loss is expressed in additive way for form and frictional losses. The general friction factor correlations and form drag coefficients available in the open literatures are used to the model. As the results, the model shows better predictions than the existing ones for the non-mixing grids, and reasonable agreements with the available experimental data for mixing grids. Therefore it is concluded that the proposed model for pressure drop can provide sufficiently good approximation for grid optimization and design calculation in advanced grid development. 7 refs., 3 figs., 3 tabs. (Author)

Improving immunization in Afghanistan: results from a cross-sectional community-based survey to assess routine immunization coverage

Directory of Open Access Journals (Sweden)

Raveesha R. Mugali

2017-04-01

Full Text Available Abstract Background Despite progress in recent years, Afghanistan is lagging behind in realizing the full potential of immunization. The country is still endemic for polio transmission and measles outbreaks continue to occur. In spite of significant reductions over the past decade, the mortality rate of children under 5 years of age continues to remain high at 91 per 1000 live births. Methods The study was a descriptive community-based cross sectional household survey. The survey aimed to estimate the levels of immunization coverage at national and province levels. Specific objectives are to: establish valid baseline information to monitor progress of the immunization program; identify reasons why children are not immunized; and make recommendations to enhance access and quality of immunization services in Afghanistan. The survey was carried out in all 34 provinces of the country, with a sample of 6125 mothers of children aged 12–23 months. Results Nationally, 51% of children participating in the survey received all doses of each antigen irrespective of the recommended date of immunization or recommended interval between doses. About 31% of children were found to be partially vaccinated. Reasons for partial vaccination included: place to vaccinate child too far (23%, not aware of the need of vaccination (17%, no faith in vaccination (16%, mother was too busy (15%, and fear of side effects (11%. Conclusion The innovative mechanism of contracting out delivery of primary health care services in Afghanistan, including immunization, to non-governmental organizations is showing some positive results in quickly increasing coverage of essential interventions, including routine immunization. Much ground still needs to be covered with proper planning and management of resources in order to improve the immunization coverage in Afghanistan and increase survival and health status of its children.

Research on the comparison of extension mechanism of cellular automaton based on hexagon grid and rectangular grid

Science.gov (United States)

Zhai, Xiaofang; Zhu, Xinyan; Xiao, Zhifeng; Weng, Jie

2009-10-01

Historically, cellular automata (CA) is a discrete dynamical mathematical structure defined on spatial grid. Research on cellular automata system (CAS) has focused on rule sets and initial condition and has not discussed its adjacency. Thus, the main focus of our study is the effect of adjacency on CA behavior. This paper is to compare rectangular grids with hexagonal grids on their characteristics, strengths and weaknesses. They have great influence on modeling effects and other applications including the role of nearest neighborhood in experimental design. Our researches present that rectangular and hexagonal grids have different characteristics. They are adapted to distinct aspects, and the regular rectangular or square grid is used more often than the hexagonal grid. But their relative merits have not been widely discussed. The rectangular grid is generally preferred because of its symmetry, especially in orthogonal co-ordinate system and the frequent use of raster from Geographic Information System (GIS). However, in terms of complex terrain, uncertain and multidirectional region, we have preferred hexagonal grids and methods to facilitate and simplify the problem. Hexagonal grids can overcome directional warp and have some unique characteristics. For example, hexagonal grids have a simpler and more symmetric nearest neighborhood, which avoids the ambiguities of the rectangular grids. Movement paths or connectivity, the most compact arrangement of pixels, make hexagonal appear great dominance in the process of modeling and analysis. The selection of an appropriate grid should be based on the requirements and objectives of the application. We use rectangular and hexagonal grids respectively for developing city model. At the same time we make use of remote sensing images and acquire 2002 and 2005 land state of Wuhan. On the base of city land state in 2002, we make use of CA to simulate reasonable form of city in 2005. Hereby, these results provide a proof of

Development of structural technology for a high performance spacer grid

International Nuclear Information System (INIS)

Song, Kee Nam; Kim, H. K.; Kang, H. S.

2003-03-01

A spacer grid in a LWR fuel assembly is a key structural component to support fuel rods and to enhance the heat transfer from the fuel rod to the coolant. In this research, the main research items are the development of inherent and high performance spacer grid shapes, the establishment of mechanical/structural analysis and test technology, and the set-up of basic test facilities for the spacer grid. The main research areas and results are as follows. 1. 14 different spacer grid candidates have been invented and applied for domestic and US patents. Among the candidates six are chosen from the patent. 2. Two kinds of spacer grids are finally selected for the advanced LWR fuel after detailed performance tests on the candidates and commercial spacer grids from a mechanical/structural point of view. According to the test results the features of the selected spacer grids are better than those of the commercial spacer grids. 3. Four kinds of basic test facilities are set up and the relevant test technologies are established. 4. Mechanical/structural analysis models and technology for spacer grid performance are developed and the analysis results are compared with the test results to enhance the reliability of the models

Replica consistency in a Data Grid

International Nuclear Information System (INIS)

Domenici, Andrea; Donno, Flavia; Pucciani, Gianni; Stockinger, Heinz; Stockinger, Kurt

2004-01-01

A Data Grid is a wide area computing infrastructure that employs Grid technologies to provide storage capacity and processing power to applications that handle very large quantities of data. Data Grids rely on data replication to achieve better performance and reliability by storing copies of data sets on different Grid nodes. When a data set can be modified by applications, the problem of maintaining consistency among existing copies arises. The consistency problem also concerns metadata, i.e., additional information about application data sets such as indices, directories, or catalogues. This kind of metadata is used both by the applications and by the Grid middleware to manage the data. For instance, the Replica Management Service (the Grid middleware component that controls data replication) uses catalogues to find the replicas of each data set. Such catalogues can also be replicated and their consistency is crucial to the correct operation of the Grid. Therefore, metadata consistency generally poses stricter requirements than data consistency. In this paper we report on the development of a Replica Consistency Service based on the middleware mainly developed by the European Data Grid Project. The paper summarises the main issues in the replica consistency problem, and lays out a high-level architectural design for a Replica Consistency Service. Finally, results from simulations of different consistency models are presented

Demagnifying electron projection with grid masks

International Nuclear Information System (INIS)

Politycki, A.; Meyer, A.

1978-01-01

Tightly toleranced micro- and submicrostructures with smooth edges were realized by using transmission masks with an improved supporting grid (width of traverses 0.8 μm). Local edge shift due to the proximity effect is kept at a minimum. Supporting grids with stil narrower traverses (0.5 μm) were prepared by generating the grid pattern by electron beam writing. Masks of this kind allow projection at a demagnification ratio of 1:4, resulting in large image fields. (orig.) [de

LGBT Coverage in U.S. Dental Schools and Dental Hygiene Programs: Results of a National Survey.

Science.gov (United States)

Hillenburg, Kenneth L; Murdoch-Kinch, Carol A; Kinney, Janet S; Temple, Henry; Inglehart, Marita R

2016-12-01

The aims of this study were to assess curricular coverage of lesbian, gay, bisexual, and transgender (LGBT) content in U.S. and Canadian dental schools and U.S. dental hygiene programs, including hours of LGBT content, pedagogy used, and assessment methods, and to determine whether respondents perceived their institution's coverage as adequate. Data were collected from academic deans at 32 U.S. and two Canadian dental schools and from program directors at 71 U.S. dental hygiene programs (response rates 49%, 20%, 23%, respectively). The results showed that 29% of responding dental schools and 48% of responding dental hygiene programs did not cover LGBT content. Among the respondents, dental schools dedicated on average 3.68 hours and dental hygiene programs 1.25 hours in required settings to LGBT content. Lectures (dental schools 68%, dental hygiene programs 45%) and small group instruction (43%, 25%) were reported as the most common methodology used in teaching this content. Most of the responding dental schools and dental hygiene programs covered HIV (85%, 53%), oral disease risk (63%, 54%), and barriers to accessing health care for LGBT people (58%, 38%). Up to a third reported no need for coverage of topics such as sexual orientation (21%, 32%), coming out (29%, 37%), transitioning (29%, 38%), and sex reassignment surgery (32%, 35%). Assessment was through written examinations (41%, 30%) and faculty-observed patient interactions (21%, 23%); some respondents (20%, 33%) reported no assessment of learning outcomes. The most frequently endorsed strategies for increasing LGBT content were receiving curricular material focusing on LGBT-related health issues and health disparities and having trained faculty to teach LGBT content.

Women's Health Insurance Coverage

Science.gov (United States)

... Women's Health Policy Women’s Health Insurance Coverage Women’s Health Insurance Coverage Published: Oct 31, 2017 Facebook Twitter LinkedIn ... that many women continue to face. Sources of Health Insurance Coverage Employer-Sponsored Insurance: Approximately 57.9 million ...

Grid Databases for Shared Image Analysis in the MammoGrid Project

CERN Document Server

Amendolia, S R; Hauer, T; Manset, D; McClatchey, R; Odeh, M; Reading, T; Rogulin, D; Schottlander, D; Solomonides, T

2004-01-01

The MammoGrid project aims to prove that Grid infrastructures can be used for collaborative clinical analysis of database-resident but geographically distributed medical images. This requires: a) the provision of a clinician-facing front-end workstation and b) the ability to service real-world clinician queries across a distributed and federated database. The MammoGrid project will prove the viability of the Grid by harnessing its power to enable radiologists from geographically dispersed hospitals to share standardized mammograms, to compare diagnoses (with and without computer aided detection of tumours) and to perform sophisticated epidemiological studies across national boundaries. This paper outlines the approach taken in MammoGrid to seamlessly connect radiologist workstations across a Grid using an "information infrastructure" and a DICOM-compliant object model residing in multiple distributed data stores in Italy and the UK

Multigrid on unstructured grids using an auxiliary set of structured grids

Energy Technology Data Exchange (ETDEWEB)

Douglas, C.C.; Malhotra, S.; Schultz, M.H. [Yale Univ., New Haven, CT (United States)

1996-12-31

Unstructured grids do not have a convenient and natural multigrid framework for actually computing and maintaining a high floating point rate on standard computers. In fact, just the coarsening process is expensive for many applications. Since unstructured grids play a vital role in many scientific computing applications, many modifications have been proposed to solve this problem. One suggested solution is to map the original unstructured grid onto a structured grid. This can be used as a fine grid in a standard multigrid algorithm to precondition the original problem on the unstructured grid. We show that unless extreme care is taken, this mapping can lead to a system with a high condition number which eliminates the usefulness of the multigrid method. Theorems with lower and upper bounds are provided. Simple examples show that the upper bounds are sharp.

Asymmetrical Grid Fault Ride-Through Strategy of Three-phase Grid-connected Inverter Considering Network Impedance Impact in Low Voltage Grid

DEFF Research Database (Denmark)

Guo, Xiaoqiang; Zhang, Xue; Wang, Baocheng

2014-01-01

This letter presents a new control strategy of threephase grid-connected inverter for the positive sequence voltage recovery and negative sequence voltage reduction under asymmetrical grid faults. Unlike the conventional control strategy based on an assumption that the network impedance is mainly...... of the proposed solution for the flexible voltage support in a low-voltage grid, where thenetwork impedance is mainly resistive.......This letter presents a new control strategy of threephase grid-connected inverter for the positive sequence voltage recovery and negative sequence voltage reduction under asymmetrical grid faults. Unlike the conventional control strategy based on an assumption that the network impedance is mainly...... inductive, the proposed control strategy is more flexible and effective by considering the network impedance impact, which is of great importance for the high penetration of grid-connected renewable energy systems into low-voltage grids. The experimental tests are carried out to validate the effectiveness...

Nondestructive measurement of the grid ratio using a single image

International Nuclear Information System (INIS)

Pasciak, A. S.; Jones, A. Kyle

2009-01-01

The antiscatter grid is an essential part of modern radiographic systems. Since the introduction of the antiscatter grid, however, there have been few methods proposed for acceptance testing and verification of manufacturer-supplied grid specifications. The grid ratio (r) is an important parameter describing the antiscatter grid because it affects many other grid quality metrics, such as the contrast improvement ratio (K), primary transmission (T p ), and scatter transmission (T s ). Also, the grid ratio in large part determines the primary clinical use of the grid. To this end, the authors present a technique for the nondestructive measurement of the grid ratio of antiscatter grids. They derived an equation that can be used to calculate the grid ratio from a single off-focus flat field image by exploiting the relationship between grid cutoff and off-focus distance. The calculation can be performed by hand or with included analysis software. They calculated the grid ratios of several different grids throughout the institution, and afterward they destructively measured the grid ratio of a nominal r8 grid previously evaluated with the method. They also studied the sensitivity of the method to technical factors and choice of parameters. With one exception, the results for the grids found in the institution were in agreement with the manufacturer's specifications and international standards. The nondestructive evaluation of the r8 grid indicated a ratio of 7.3, while the destructive measurement indicated a ratio of 7.53±0.28. Repeated evaluations of the same grid yielded consistent results. The technique provides the medical physicist with a new tool for quantitative evaluation of the grid ratio, an important grid performance criterion. The method is robust and repeatable when appropriate choices of technical factors and other parameters are made.

The GRID seminar

CERN Multimedia

CERN. Geneva HR-RFA

2006-01-01

The Grid infrastructure is a key part of the computing environment for the simulation, processing and analysis of the data of the LHC experiments. These experiments depend on the availability of a worldwide Grid infrastructure in several aspects of their computing model. The Grid middleware will hide much of the complexity of this environment to the user, organizing all the resources in a coherent virtual computer center. The general description of the elements of the Grid, their interconnections and their use by the experiments will be exposed in this talk. The computational and storage capability of the Grid is attracting other research communities beyond the high energy physics. Examples of these applications will be also exposed during the presentation.

Buckling behavior analysis of spacer grid by lateral impact load

International Nuclear Information System (INIS)

Yoon, Kyung Ho; Kang, Heung Seok; Kim, Hyung Kyu; Song, Kee Nam

2000-05-01

The spacer grid is one of the main structural components in the fuel assembly, Which supports the fuel rods, guides cooling water, and protects the system from an external impact load, such as earthquakes. Therefore, the mechanical and structural properties of the spacer grids must be extensively examined while designing it. In this report, free fall type shock tests on the several kinds of the specimens of the spacer grids were also carried out in order to compare the results among the candidate grids. A free fall carriage on the specimen accomplishes the test. In addition to this, a finite element method for predicting the critical impact strength of the spacer grids is described. FE method on the buckling behavior of the spacer grids are performed for a various array of sizes of the grids considering that the spacer grid is an assembled structure with thin-walled plates and imposing proper boundary conditions by nonlinear dynamic impact analysis using ABAQUS/explicit code. The simulated results results also similarly predicted the local buckling phenomena and were found to give good correspondence with the shock test results

Extending Coverage and Lifetime of K-coverage Wireless Sensor Networks Using Improved Harmony Search

Directory of Open Access Journals (Sweden)

Shohreh Ebrahimnezhad

2011-07-01

Full Text Available K-coverage wireless sensor networks try to provide facilities such that each hotspot region is covered by at least k sensors. Because, the fundamental evaluation metrics of such networks are coverage and lifetime, proposing an approach that extends both of them simultaneously has a lot of interests. In this article, it is supposed that two kinds of nodes are available: static and mobile. The proposed method, at first, tries to balance energy among sensor nodes using Improved Harmony Search (IHS algorithm in a k-coverage and connected wireless sensor network in order to achieve a sensor node deployment. Also, this method proposes a suitable place for a gateway node (Sink that collects data from all sensors. Second, in order to prolong the network lifetime, some of the high energy-consuming mobile nodes are moved to the closest positions of low energy-consuming ones and vice versa after a while. This leads increasing the lifetime of network while connectivity and k-coverage are preserved. Through computer simulations, experimental results verified that the proposed IHS-based algorithm found better solution compared to some related methods.

Calculation approaches for grid usage fees to influence the load curve in the distribution grid level; Berechnungsansaetze fuer Netznutzungsentgelte zur Beeinflussung des Lastverlaufs in der Verteilernetzebene

Energy Technology Data Exchange (ETDEWEB)

Illing, Bjoern

2014-09-08

Dominated by the energy policy the decentralized German energy market is changing. One mature target of the government is to increase the contribution of renewable generation to the gross electricity consumption. In order to achieve this target disadvantages like an increased need for capacity management occurs. Load reduction and variable grid fees offer the grid operator solutions to realize capacity management by influencing the load profile. The evolution of the current grid fees towards more causality is required to adapt these approaches. Two calculation approaches are developed in this assignment. On the one hand multivariable grid fees keeping the current components demand and energy charge. Additional to the grid costs grid load dependent parameters like the amount of decentralized feed-ins, time and local circumstances as well as grid capacities are considered. On the other hand the grid fee flat-rate which represents a demand based model on a monthly level. Both approaches are designed to meet the criteria for future grid fees. By means of a case study the effects of the grid fees on the load profile at the low voltage grid is simulated. Thereby the consumption is represented by different behaviour models and the results are scaled at the benchmark grid area. The resulting load curve is analyzed concerning the effects of peak load reduction as well as the integration of renewable energy sources. Additionally the combined effect of grid fees and electricity tariffs is evaluated. Finally the work discusses the launching of grid fees in the tense atmosphere of politics, legislation and grid operation. Results of this work are two calculation approaches designed for grid operators to define the grid fees. Multivariable grid fees are based on the current calculation scheme. Hereby demand and energy charges are weighted by time, locational and load related dependencies. The grid fee flat-rate defines a limitation in demand extraction. Different demand levels

How should grid operators govern smart grid innovation projects? An embedded case study approach

International Nuclear Information System (INIS)

Reuver, Mark de; Lei, Telli van der; Lukszo, Zofia

2016-01-01

Grid operators increasingly have to collaborate with other actors in order to realize smart grid innovations. For routine maintenance, grid operators typically acquire technologies in one-off transactions, but the innovative nature of smart grid projects may require more collaborate relationships. This paper studies how a transactional versus relational approach to governing smart grid innovation projects affects incentives for other actors to collaborate. We analyse 34 cases of smart grid innovation projects based on extensive archival data as well as interviews. We find that projects relying on relational governance are more likely to provide incentives for collaboration. Especially non-financial incentives such as reputational benefits and shared intellectual property rights are more likely to be found in projects relying on relational governance. Policy makers that wish to stimulate smart grid innovation projects should consider stimulating long-term relationships between grid operators and third parties, because such relationships are more likely to produce incentives for collaboration. - Highlights: • Smart grids require collaboration between grid operators and other actors. • We contrast transactional and relational governance of smart grid projects. • Long-term relations produce more incentives for smart grid collaboration. • Non-financial incentives are more important in long-term relations. • Policy makers should stimulate long-term relations to stimulate smart grids.

Investigation of thick grid plasma switches for thermionic system output voltage

International Nuclear Information System (INIS)

Alekseev, N.I.; Kaplan, V.B.; Martsinovski, A.M.

1992-01-01

Plasma switches (Cs and Cs-Ba tacitrons PS) with thick grid have grid with thickness more than mesh aperture size. These grids have some advantages as compared with small-scale/1.2/ones. For instance, much more electrical strength. This paper contains the thick-grid investigation results: the grid controls efficiency, the plasma parameters, probe researches of these parameters at conductive state and their variety during the process of quenching. The results showed the thick-grid PS plasma differed from the thin-grid PS significantly at the stationary state as well as by quenching dynamic features

Characterization of Slosh Damping for Ortho-Grid and Iso-Grid Internal Tank Structures

Science.gov (United States)

Westra, Douglas G.; Sansone, Marco D.; Eberhart, Chad J.; West, Jeffrey S.

2016-01-01

Grid stiffened tank structures such as Ortho-Grid and Iso-Grid are widely used in cryogenic tanks for providing stiffening to the tank while reducing mass, compared to tank walls of constant cross-section. If the structure is internal to the tank, it will positively affect the fluid dynamic behavior of the liquid propellant, in regard to fluid slosh damping. As NASA and commercial companies endeavor to explore the solar system, vehicles will by necessity become more mass efficient, and design margin will be reduced where possible. Therefore, if the damping characteristics of the Ortho-Grid and Iso-Grid structure is understood, their positive damping effect can be taken into account in the systems design process. Historically, damping by internal structures has been characterized by rules of thumb and for Ortho-Grid, empirical design tools intended for slosh baffles of much larger cross-section have been used. There is little or no information available to characterize the slosh behavior of Iso-Grid internal structure. Therefore, to take advantage of these structures for their positive damping effects, there is much need for obtaining additional data and tools to characterize them. Recently, the NASA Marshall Space Flight Center conducted both sub-scale testing and computational fluid dynamics (CFD) simulations of slosh damping for Ortho-Grid and Iso-Grid tanks for cylindrical tanks containing water. Enhanced grid meshing techniques were applied to the geometrically detailed and complex Ortho-Grid and Iso-Grid structures. The Loci-STREAM CFD program with the Volume of Fluid Method module for tracking and locating the water-air fluid interface was used to conduct the simulations. The CFD simulations were validated with the test data and new empirical models for predicting damping and frequency of Ortho-Grid and Iso-Grid structures were generated.

Future electrical distribution grids: Smart Grids

International Nuclear Information System (INIS)

Hadjsaid, N.; Sabonnadiere, J.C.; Angelier, J.P.

2010-01-01

The new energy paradigm faced by distribution network represents a real scientific challenge. Thus, national and EU objectives in terms of environment and energy efficiency with resulted regulatory incentives for renewable energies, the deployment of smart meters and the need to respond to changing needs including new uses related to electric and plug-in hybrid vehicles introduce more complexity and favour the evolution towards a smarter grid. The economic interest group in Grenoble IDEA in connection with the power laboratory G2ELab at Grenoble Institute of technology, EDF and Schneider Electric are conducting research on the electrical distribution of the future in presence of distributed generation for ten years.Thus, several innovations emerged in terms of flexibility and intelligence of the distribution network. One can notice the intelligence solutions for voltage control, the tools of network optimization, the self-healing techniques, the innovative strategies for connecting distributed and intermittent generation or load control possibilities for the distributor. All these innovations are firmly in the context of intelligent networks of tomorrow 'Smart Grids'. (authors)

Robust Grid-Current-Feedback Resonance Suppression Method for LCL-Type Grid-Connected Inverter Connected to Weak Grid

DEFF Research Database (Denmark)

Zhou, Xiaoping; Zhou, Leming; Chen, Yandong

2018-01-01

In this paper, a robust grid-current-feedback reso-nance suppression (GCFRS) method for LCL-type grid-connected inverter is proposed to enhance the system damping without introducing the switching noise and eliminate the impact of control delay on system robustness against grid-impedance variation....... It is composed of GCFRS method, the full duty-ratio and zero-beat-lag PWM method, and the lead-grid-current-feedback-resonance-suppression (LGCFRS) method. Firstly, the GCFRS is used to suppress the LCL-resonant peak well and avoid introducing the switching noise. Secondly, the proposed full duty-ratio and zero......-beat-lag PWM method is used to elimi-nate the one-beat-lag computation delay without introducing duty cycle limitations. Moreover, it can also realize the smooth switching from positive to negative half-wave of the grid current and improve the waveform quality. Thirdly, the proposed LGCFRS is used to further...

Grid connectivity issues and the importance of GCC. [GCC - Grid Code Compliance

Energy Technology Data Exchange (ETDEWEB)

Das, A.; Schwartz, M.-K. [GL Renewable Certification, Malleswaram, Bangalore (India)

2012-07-01

In India, the wind energy is concentrated in rural areas with a very high penetration. In these cases, the wind power has an increasing influence on the power quality on the grids. Another aspect is the influence of weak grids on the operation of wind turbines. Hence it becomes very much essential to introduce such a strong grid code which is particularly applicable to wind sector and suitable for Indian environmental grid conditions. This paper focuses on different international grid codes and their requirement with regard to the connection of wind farms to the electric power systems to mitigate the grid connectivity issues. The requirements include the ways to achieve voltage and frequency stability in the grid-tied wind power system. In this paper, comparative overview and analysis of the main grid connecting requirements will be conducted, comprising several national and regional codes from many countries where high wind penetration levels have been achieved or are expected in the future. The objective of these requirements is to provide wind farms with the control and regulation capabilities encountered in conventional power plants and are necessary for the safe, reliable and economic operation of the power system. This paper also provides a brief idea on the Grid Code Compliance (GCC) certification procedure implemented by the leading accredited certifying body like Germanischer Lloyd Renewables Certification (GL RC), who checks the conformity of the wind turbines as per region specific grid codes. (Author)

Results from Operational Testing of the Siemens Smart Grid-Capable Electric Vehicle Supply Equipment

Energy Technology Data Exchange (ETDEWEB)

Bennett, Brion [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-05-01

The Idaho National Laboratory conducted testing and analysis of the Siemens smart grid capable electric vehicle supply equipment (EVSE), which was a deliverable from Siemens for the U.S. Department of Energy FOA-554. The Idaho National Laboratory has extensive knowledge and experience in testing advanced conductive and wireless charging systems though INL’s support of the U.S. Department of Energy’s Advanced Vehicle Testing Activity. This document details the findings from the EVSE operational testing conducted at the Idaho National Laboratory on the Siemens smart grid capable EVSE. The testing conducted on the EVSE included energy efficiency testing, SAE J1772 functionality testing, abnormal conditions testing, and charging of a plug-in vehicle.

84-KILOMETER RADIOLOGICAL MONITORING GRID

International Nuclear Information System (INIS)

L. Roe

2000-01-01

The purpose of this calculation is to document the development of a radial grid that is suitable for evaluating the pathways and potential impacts of a release of radioactive materials to the environment within a distance of 84 kilometers (km). The center of the grid represents an approximate location from which a potential release of radioactive materials could originate. The center is located on Nevada State Plane coordinates Northing 765621.5, and Easting 570433.6, which is on the eastern side of Exile Hill at the Yucca Mountain site. The North Portal Pad is located over this point. The grid resulting from this calculation is intended for use primarily in the Radiological Monitoring Program (RadMP). This grid also is suitable for use in Biosphere Modeling and other Yucca Mountain Site Characteristic Project (YMP) activities that require the evaluation of data referenced by spatial or geographic coordinates

The GridShare solution: a smart grid approach to improve service provision on a renewable energy mini-grid in Bhutan

International Nuclear Information System (INIS)

Quetchenbach, T G; Harper, M J; Jacobson, A E; Robinson IV, J; Hervin, K K; Chase, N A; Dorji, C

2013-01-01

This letter reports on the design and pilot installation of GridShares, devices intended to alleviate brownouts caused by peak power use on isolated, village-scale mini-grids. A team consisting of the authors and partner organizations designed, built and field-tested GridShares in the village of Rukubji, Bhutan. The GridShare takes an innovative approach to reducing brownouts by using a low cost device that communicates the state of the grid to its users and regulates usage before severe brownouts occur. This demand-side solution encourages users to distribute the use of large appliances more evenly throughout the day, allowing power-limited systems to provide reliable, long-term renewable electricity to these communities. In the summer of 2011, GridShares were installed in every household and business connected to the Rukubji micro-hydro mini-grid, which serves approximately 90 households with a 40 kW nominal capacity micro-hydro system. The installation was accompanied by an extensive education program. Following the installation of the GridShares, the occurrence and average length of severe brownouts, which had been caused primarily by the use of electric cooking appliances during meal preparation, decreased by over 92%. Additionally, the majority of residents surveyed stated that now they are more certain that their rice will cook well and that they would recommend installing GridShares in other villages facing similar problems. (letter)

Bayesian grid matching

DEFF Research Database (Denmark)

Hartelius, Karsten; Carstensen, Jens Michael

2003-01-01

A method for locating distorted grid structures in images is presented. The method is based on the theories of template matching and Bayesian image restoration. The grid is modeled as a deformable template. Prior knowledge of the grid is described through a Markov random field (MRF) model which r...

Techniques for grid manipulation and adaptation. [computational fluid dynamics

Science.gov (United States)

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.

Survey results show that adults are willing to pay higher insurance premiums for generous coverage of specialty drugs.

Science.gov (United States)

Romley, John A; Sanchez, Yuri; Penrod, John R; Goldman, Dana P

2012-04-01

Generous coverage of specialty drugs for cancer and other diseases may be valuable not only for sick patients currently using these drugs, but also for healthy people who recognize the potential need for them in the future. This study estimated how healthy people value insurance coverage of specialty drugs, defined as high-cost drugs that treat cancer and other serious health conditions like multiple sclerosis, by quantifying willingness to pay via a survey. US adults were estimated to be willing to pay an extra $12.94 on average in insurance premiums per month for generous specialty-drug coverage--in effect, $2.58 for every dollar in out-of-pocket costs that they would expect to pay with a less generous insurance plan. Given the value that people assign to generous coverage of specialty drugs, having high cost sharing on these drugs seemingly runs contrary to what people value in their health insurance.

The LHCb Grid Simulation

CERN Multimedia

Baranov, Alexander

2016-01-01

The LHCb Grid access if based on the LHCbDirac system. It provides access to data and computational resources to researchers with different geographical locations. The Grid has a hierarchical topology with multiple sites distributed over the world. The sites differ from each other by their number of CPUs, amount of disk storage and connection bandwidth. These parameters are essential for the Grid work. Moreover, job scheduling and data distribution strategy have a great impact on the grid performance. However, it is hard to choose an appropriate algorithm and strategies as they need a lot of time to be tested on the real grid. In this study, we describe the LHCb Grid simulator. The simulator reproduces the LHCb Grid structure with its sites and their number of CPUs, amount of disk storage and bandwidth connection. We demonstrate how well the simulator reproduces the grid work, show its advantages and limitations. We show how well the simulator reproduces job scheduling and network anomalies, consider methods ...

Smart grid in Denmark 2.0. Implementing three key recommendations from the Smart Grid Network. [DanGrid]; Smart Grid i Danmark 2.0. Implementering af tre centrale anbefalinger fra Smart Grid netvaerket

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-11-01

In 2011 the Smart Grid Network, established by the Danish Climate and Energy minister in 2010, published a report which identifies 35 recommendations for implementing smart grid in Denmark. The present report was prepared by the Danish Energy Association and Energinet.dk and elaborates three of these recommendations: Concept for controlling the power system; Information model for the dissemination of data; Roadmap for deployment of smart grid. Concept of Smart Grid: The concept mobilizes and enables electric power demand response and production from smaller customers. This is done by customers or devices connected to the power system modify their behavior to meet the needs of the power system. The concept basically distinguishes between two different mechanisms to enable flexibility. One is the use of price signals (variable network tariffs and electricity prices), which gives customers a financial incentive to move their electricity consumption and production to times when it is of less inconvenience to the power system. The second is flexibility products, where a pre-arranged and well-specified performance - for example, a load reduction in a defined network area - can be activated as required by grid operators and / or Energinet.dk at an agreed price. Information Model for Disseminating Data: The future power system is complex with a large number of physical units, companies and individuals are actively involved in the power system. Similarly, the amount of information needed to be collected, communicated and processed grows explosively, and it is therefore essential to ensure a well-functioning IT infrastructure. A crucial element is a standardized information model in the Danish power system. The concept therefore indicates to use international standards to define an information model. Roadmap Focusing on Grid Companies' Role: There is a need to remove two key barriers. The first barrier is that the existing regulation does not support the grid using

Synchronization method for grid integrated battery storage systems during asymmetrical grid faults

Directory of Open Access Journals (Sweden)

Popadić Bane

2017-01-01

Full Text Available This paper aims at presenting a robust and reliable synchronization method for battery storage systems during asymmetrical grid faults. For this purpose, a Matlab/Simulink based model for testing of the power electronic interface between the grid and the battery storage systems has been developed. The synchronization method proposed in the paper is based on the proportional integral resonant controller with the delay signal cancellation. The validity of the synchronization method has been verified using the advanced laboratory station for the control of grid connected distributed energy sources. The proposed synchronization method has eliminated unfavourable components from the estimated grid angular frequency, leading to the more accurate and reliable tracking of the grid voltage vector positive sequence during both the normal operation and the operation during asymmetrical grid faults. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 042004: Integrated and Interdisciplinary Research entitled: Smart Electricity Distribution Grids Based on Distribution Management System and Distributed Generation

European electricity grid. Status and perspective

International Nuclear Information System (INIS)

Maillard, Dominique

2010-01-01

There is no doubt about the need to expand and modernize the European electricity grid, especially in order to allow renewable energies to be fed stochastically into existing systems. As it is hardly possible at the present time and also in the near future to store electricity on a major scale and at adequate prices, electricity must be transmitted from the point of generation to the point of consumption directly and in real time. The development of grid systems, including cross-border transmission systems, is still behind expectations. This is not due to a shortage of projects or a lack of interest on the part of grid operators; the necessary political support is available as well, and investments at present are covered by the feed tariffs. The problem is the lack of acceptance. It is difficult to obtain new permits or commission new grids. This problem of the licensing authorities often results in considerable delays. Consequently, it is up to the grid operators to handle this situation and promote new, intelligent grid systems in an effort to achieve acceptance of a technical-scale infrastructure. This includes transparency in grid expansion, exchange with the public in order to reach mutual understanding and trust and also find compromises as well as the willingness to discuss various approaches to solutions (underground routing, upgrading of existing grid systems, smart systems, and intelligent designs) so as to optimize the use of the existing infrastructure. (orig.)

Increased Observability in Electric Distribution Grids

DEFF Research Database (Denmark)

Prostejovsky, Alexander Maria

infrastructure in distribution grids. Strong emphasis is placed on experimental verifications of the investigated concepts wherever applicable. Electric grids are changing, and so are the roles of system operators. The interest in sustainable energy and the rapidly increasing number of Distributed Energy...... that DSO areas are not necessarily self-sufficient. Missing power is covered by neighbouring areas to confine problems in a small region, which is demonstrated in SYSLAB on a two-area, grid-connected setup. The results highlight the advantages of harnessing the information obtained directly from...

Smart-Grid Investments, Regulation and Organization

DEFF Research Database (Denmark)

Agrell, Per J.; Bogetoft, Peter

on the network tasks, assets and costs and contrast this with the assumptions implicit or explicit in current economic network regulation. The resulting challenge is identified as the change in the direction of higher asymmetry of information and higher capital intensity, combined with ambiguities in terms......Worldwide, but in particular in North America and Europe, the grid infrastructure managers are facing demands for reinvestments in new assets with higher on-grid and off-grid functionality in order to promote energy efficiency and low-carbon conversion of the energy sector. To meet societal policy...

A Micro-Grid Battery Storage Management

DEFF Research Database (Denmark)

Mahat, Pukar; Escribano Jiménez, Jorge; Moldes, Eloy Rodríguez

2013-01-01

An increase in number of distributed generation (DG) units in power system allows the possibility of setting-up and operating micro-grids. In addition to a number of technical advantages, micro-grid operation can also reduce running costs by optimally scheduling the generation and/or storage...... systems under its administration. This paper presents an optimized scheduling of a micro-grid battery storage system that takes into account the next-day forecasted load and generation profiles and spot electricity prices. Simulation results show that the battery system can be scheduled close to optimal...

Flexible operation of parallel grid-connecting converters under unbalanced grid voltage

DEFF Research Database (Denmark)

Lu, Jinghang; Savaghebi, Mehdi; Guerrero, Josep M.

2017-01-01

-link voltage ripple, and overloading. Moreover, under grid voltage unbalance, the active power delivery ability is decreased due to the converter's current rating limitation. In this paper, a thorough study on the current limitation of the grid-connecting converter under grid voltage unbalance is conducted....... In addition, based on the principle that total output active power should be oscillation free, a coordinated control strategy is proposed for the parallel grid-connecting converters. The case study has been conducted to demonstrate the effectiveness of this proposed control strategy....

Battery Storage Systems as Grid-Balancing Measure in Low-Voltage Distribution Grids with Distributed Generation

Directory of Open Access Journals (Sweden)

Bernhard Faessler

2017-12-01

Full Text Available Due to the promoted integration of renewable sources, a further growth of strongly transient, distributed generation is expected. Thus, the existing electrical grid may reach its physical limits. To counteract this, and to fully exploit the viable potential of renewables, grid-balancing measures are crucial. In this work, battery storage systems are embedded in a grid simulation to evaluate their potential for grid balancing. The overall setup is based on a real, low-voltage distribution grid topology, real smart meter household load profiles, and real photovoltaics load data. An autonomous optimization routine, driven by a one-way communicated incentive, determines the prospective battery operation mode. Different battery positions and incentives are compared to evaluate their impact. The configurations incorporate a baseline simulation without storage, a single, central battery storage or multiple, distributed battery storages which together have the same power and capacity. The incentives address either market conditions, grid balancing, optimal photovoltaic utilization, load shifting, or self-consumption. Simulations show that grid-balancing incentives result in lowest peak-to-average power ratios, while maintaining negligible voltage changes in comparison to a reference case. Incentives reflecting market conditions for electricity generation, such as real-time pricing, negatively influence the power quality, especially with respect to the peak-to-average power ratio. A central, feed-in-tied storage performs better in terms of minimizing the voltage drop/rise and shows lower distribution losses, while distributed storages attached at nodes with electricity generation by photovoltaics achieve lower peak-to-average power ratios.

Phase-lock loop of Grid-connected Voltage Source Converter under non-ideal grid condition

DEFF Research Database (Denmark)

Wang, Haojie; Sun, Hai; Han, Minxiao

2015-01-01

It is a normal practice that the DC micro-grid is connected to AC main grid through Grid-connected Voltage Source Converter (G-VSC) for voltage support. Accurate control of DC micro-grid voltage is difficult for G-VSC under unbalanced grid condition as the fundamental positive-sequence component...... and distorted system voltage the proposed PLL can accurately detect the fundamental positive-sequence component of grid voltage thus accurate control of DC micro-grid voltage can be realized....... phase information cannot be accurately tracked. Based on analysis of the cause of double-frequency ripple when unbalance exists in main grid, a phase-locked loop (PLL) detection technique is proposed. Under the conditions of unsymmetrical system voltage, varying system frequency, single-phase system...

Terrorism and nuclear damage coverage

International Nuclear Information System (INIS)

Horbach, N. L. J. T.; Brown, O. F.; Vanden Borre, T.

2004-01-01

This paper deals with nuclear terrorism and the manner in which nuclear operators can insure themselves against it, based on the international nuclear liability conventions. It concludes that terrorism is currently not covered under the treaty exoneration provisions on 'war-like events' based on an analysis of the concept on 'terrorism' and travaux preparatoires. Consequently, operators remain liable for nuclear damage resulting from terrorist acts, for which mandatory insurance is applicable. Since nuclear insurance industry looks at excluding such insurance coverage from their policies in the near future, this article aims to suggest alternative means for insurance, in order to ensure adequate compensation for innocent victims. The September 11, 2001 attacks at the World Trade Center in New York City and the Pentagon in Washington, DC resulted in the largest loss in the history of insurance, inevitably leading to concerns about nuclear damage coverage, should future such assaults target a nuclear power plant or other nuclear installation. Since the attacks, some insurers have signalled their intentions to exclude coverage for terrorism from their nuclear liability and property insurance policies. Other insurers are maintaining coverage for terrorism, but are establishing aggregate limits or sublimits and are increasing premiums. Additional changes by insurers are likely to occur. Highlighted by the September 11th events, and most recently by those in Madrid on 11 March 2004, are questions about how to define acts of terrorism and the extent to which such are covered under the international nuclear liability conventions and various domestic nuclear liability laws. Of particular concern to insurers is the possibility of coordinated simultaneous attacks on multiple nuclear facilities. This paper provides a survey of the issues, and recommendations for future clarifications and coverage options.(author)

Smart grid security innovative solutions for a modernized grid

CERN Document Server

Skopik, Florian

2015-01-01

The Smart Grid security ecosystem is complex and multi-disciplinary, and relatively under-researched compared to the traditional information and network security disciplines. While the Smart Grid has provided increased efficiencies in monitoring power usage, directing power supplies to serve peak power needs and improving efficiency of power delivery, the Smart Grid has also opened the way for information security breaches and other types of security breaches. Potential threats range from meter manipulation to directed, high-impact attacks on critical infrastructure that could bring down regi

Impact of network topology on synchrony of oscillatory power grids

Energy Technology Data Exchange (ETDEWEB)

Rohden, Martin; Sorge, Andreas; Witthaut, Dirk [Network Dynamics, Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen (Germany); Timme, Marc [Network Dynamics, Max Planck Institute for Dynamics and Self-Organization (MPIDS), 37077 Göttingen (Germany); Faculty of Physics, Georg August Universität Göttingen, Göttingen (Germany)

2014-03-15

Replacing conventional power sources by renewable sources in current power grids drastically alters their structure and functionality. In particular, power generation in the resulting grid will be far more decentralized, with a distinctly different topology. Here, we analyze the impact of grid topologies on spontaneous synchronization, considering regular, random, and small-world topologies and focusing on the influence of decentralization. We model the consumers and sources of the power grid as second order oscillators. First, we analyze the global dynamics of the simplest non-trivial (two-node) network that exhibit a synchronous (normal operation) state, a limit cycle (power outage), and coexistence of both. Second, we estimate stability thresholds for the collective dynamics of small network motifs, in particular, star-like networks and regular grid motifs. For larger networks, we numerically investigate decentralization scenarios finding that decentralization itself may support power grids in exhibiting a stable state for lower transmission line capacities. Decentralization may thus be beneficial for power grids, regardless of the details of their resulting topology. Regular grids show a specific sharper transition not found for random or small-world grids.

Macedonian transmission grid capability and development

International Nuclear Information System (INIS)

Naumoski, K.; Achkoska, E.; Paunoski, A.

2015-01-01

The main task of the transmission grid is to guarantee evacuation of electricity from production facilities and, at the same time, supply the electricity to all customers, in a secure, reliable and qualitative manner. During the last years, transmission grid goes through the period of fast and important development, as a result of implementation of renewable and new technologies and creation of internal European electricity market. Due to these reasons, capacity of the existing grid needs to be upgraded either with optimization of existing infrastructure or constructing the new transmission projects. Among the various solutions for strengthening the grid, the one with the minimal investment expenses for construction is selected. While planning the national transmission grid, MEPSO planners apply multi-scenarios analyses, in order to handle all uncertainties, particularly in the forecasts on loads, production and exchange of electricity, location and size of the new power plants, hydrological conditions, integration of renewable sources and the evolution of the electricity market. Visions for development of European transmission grid are also considered. Special attention in the development plan is paid to modelling of power systems in the region of South-Eastern Europe and covering a wider area of the regional transmission grid with simulations of various market transactions. Macedonian transmission grid is developed to satisfy all requirements for electricity production/supply and transits, irrespective which scenario will be realized on long-term basis. Transmission development plan gives the road map for grid evolution from short-term and mid-term period towards long-term horizons (15-20 years ahead). While creating long-term visions, a big challenge in front of transmission planners is implementation of NPP. The paper gives overview of the planning process of Macedonian transmission grid,comprising: definition of scenarios,planning methodology and assessment of

Grid Integration Research | Wind | NREL

Science.gov (United States)

Grid Integration Research Grid Integration Research Researchers study grid integration of wind three wind turbines with transmission lines in the background. Capabilities NREL's grid integration electric power system operators to more efficiently manage wind grid system integration. A photo of

EASE-Grid 2.0: Incremental but Significant Improvements for Earth-Gridded Data Sets

OpenAIRE

Brodzik, Mary J.; Billingsley, Brendan; Haran, Terry; Raup, Bruce; Savoie, Matthew H.

2012-01-01

Defined in the early 1990s for use with gridded satellite passive microwave data, the Equal-Area Scalable Earth Grid (EASE-Grid) was quickly adopted and used for distribution of a variety of satellite and in situ data sets. Conceptually easy to understand, EASE-Grid suffers from limitations that make it impossible to format in the widely popular GeoTIFF convention without reprojection. Importing EASE-Grid data into standard mapping software packages is nontrivial and error-prone. This article...

Grid-supported Medical Digital Library.

Science.gov (United States)

Kosiedowski, Michal; Mazurek, Cezary; Stroinski, Maciej; Weglarz, Jan

2007-01-01

Secure, flexible and efficient storing and accessing digital medical data is one of the key elements for delivering successful telemedical systems. To this end grid technologies designed and developed over the recent years and grid infrastructures deployed with their use seem to provide an excellent opportunity for the creation of a powerful environment capable of delivering tools and services for medical data storage, access and processing. In this paper we present the early results of our work towards establishing a Medical Digital Library supported by grid technologies and discuss future directions of its development. These works are part of the "Telemedycyna Wielkopolska" project aiming to develop a telemedical system for the support of the regional healthcare.

SuperGrid or SmartGrid: Competing strategies for large-scale integration of intermittent renewables?

International Nuclear Information System (INIS)

Blarke, Morten B.; Jenkins, Bryan M.

2013-01-01

This paper defines and compares two strategies for integrating intermittent renewables: SuperGrid and SmartGrid. While conventional energy policy suggests that these strategies may be implemented alongside each other, the paper identifies significant technological and socio-economic conflicts of interest between the two. The article identifies differences between a domestic strategy for the integration of intermittent renewables, vis-à-vis the SmartGrid, and a cross-system strategy, vis-à-vis the SuperGrid. Policy makers and transmission system operators must understand the need for both strategies to evolve in parallel, but in different territories, or with strategic integration, avoiding for one strategy to undermine the feasibility of the other. A strategic zoning strategy is introduced from which attentive societies as well as the global community stand to benefit. The analysis includes a paradigmatic case study from West Denmark which supports the hypothesis that these strategies are mutually exclusive. The case study shows that increasing cross-system transmission capacity jeopardizes the feasibility of SmartGrid technology investments. A political effort is required for establishing dedicated SmartGrid innovation zones, while also redefining infrastructure to avoid the narrow focus on grids and cables. SmartGrid Investment Trusts could be supported from reallocation of planned transmission grid investments to provide for the equitable development of SmartGrid strategies. - Highlights: • Compares SuperGrid and SmartGrid strategies for integrating intermittent renewables. • Identifies technological and socio-economic conflicts of interest between the two. • Proposes a strategic zoning strategy allowing for both strategies to evolve. • Presents a paradigmatic case study showing that strategies are mutually exclusive. • Proposes dedicated SmartGrid innovation zones and SmartGrid investment trusts

Mapping of grid faults and grid codes[Wind turbines

Energy Technology Data Exchange (ETDEWEB)

Iov, F. [Aalborg Univ., Inst. of Energy Technology (Denmark); Hansen, Anca D.; Soerensen, Poul; Cutululis, N.A. [Risoe National Lab. - DTU, Wind Enegy Dept., Roskilde (Denmark)

2007-06-15

The objective of this project is to investigate into the consequences of the new grid connection requirements for the fatigue and extreme loads of wind turbines. The goal is also to clarify and define possible new directions in the certification process of power plant wind turbines, namely wind turbines, which participate actively in the stabilisation of power systems. Practical experience shows that there is a need for such investigations. The grid connection requirements for wind turbines have increased significantly during the last 5-10 years. Especially the requirements for wind turbines to stay connected to the grid during and after voltage sags, imply potential challenges in the design of wind turbines. These requirements pose challenges for the design of both the electrical system and the mechanical structure of wind turbines. An overview over the frequency of grid faults and the grid connection requirements in different relevant countries is done in this report. The most relevant study cases for the quantification of the loads' impact on the wind turbines' lifetime are defined. The goal of this report is to present a mapping of different grid fault types and their frequency in different countries. The report provides also a detailed overview of the Low Voltage Ride-Through Capabilities for wind turbines in different relevant countries. The most relevant study cases for the quantification of the loads' impact on the wind turbines' lifetime are defined. (au)

Bus.py: A GridLAB-D Communication Interface for Smart Distribution Grid Simulations

Energy Technology Data Exchange (ETDEWEB)

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.

Profitability of smart grid solutions applied in power grid

Directory of Open Access Journals (Sweden)

Katić Nenad A.

2016-01-01

Full Text Available The idea of a Smart Grid solution has been developing for years, as complete solution for a power utility, consisting of different advanced technologies aimed at improving of the efficiency of operation. The trend of implementing various smart systems continues, e.g. Energy Management Systems, Grid Automation Systems, Advanced Metering Infrastructure, Smart power equipment, Distributed Energy Resources, Demand Response systems, etc. Futhermore, emerging technologies, such as energy storages, electrical vehicles or distributed generators, become integrated in distribution networks and systems. Nowadays, the idea of a Smart Grid solution becomes more realistic by full integration of all advanced operation technologies (OT within IT environment, providing the complete digitalization of an Utility (IT/OT integration. The overview of smart grid solutions, estimation of investments, operation costs and possible benefits are presented in this article, with discusison about profitability of such systems.

Application of synchronous grid-connected controller in the wind-solar-storage micro grid

OpenAIRE

Li, Hua; Ren, Yongfeng; Li, Le; Luo, Zhenpeng

2016-01-01

Recently, there has been an increasing interest in using distributed generators (DG) not only to inject power into the grid, but also to enhance the power quality. In this study, a space voltage pulse width modulation (SVPWM) control method is proposed for a synchronous grid-connected controller in a wind-solar-storage micro grid. This method is based on the appropriate topology of the synchronous controller. The wind-solar-storage micro grid is controlled to reconnect to the grid synchronous...

Ion extraction capabilities of two-grid accelerator systems

International Nuclear Information System (INIS)

Rovang, D.C.; Wilbur, P.J.

1984-02-01

An experimental investigation into the ion extraction capabilities of two-grid accelerator systems common to electrostatic ion thrusters is described. This work resulted in a large body of experimental data which facilitates the selection of the accelerator system geometries and operating parameters necessary to maximize the extracted ion current. Results suggest that the impingement-limited perveance is not dramatically affected by reductions in screen hole diameter to 0.5 mm. Impingement-limited performance is shown to depend most strongly on grid separation distance, accelerator hole diameter ratio, the discharge-to-total accelerating voltage ratio, and the net-to-total accelerating voltage ratio. Results obtained at small grid separation ratios suggest a new grid operating condition where high beam current per hole levels are achieved at a specified net accelerating voltage. It is shown that this operating condition is realized at an optimum ratio of net-to-total accelerating voltage ratio which is typically quite high. The apparatus developed for this study is also shown to be well suited measuring the electron backstreaming and electrical breakdown characteristics of two-grid accelerator systems

Analysis of turbine-grid interaction of grid-connected wind turbine using HHT

Science.gov (United States)

Chen, A.; Wu, W.; Miao, J.; Xie, D.

2018-05-01

This paper processes the output power of the grid-connected wind turbine with the denoising and extracting method based on Hilbert Huang transform (HHT) to discuss the turbine-grid interaction. At first, the detailed Empirical Mode Decomposition (EMD) and the Hilbert Transform (HT) are introduced. Then, on the premise of decomposing the output power of the grid-connected wind turbine into a series of Intrinsic Mode Functions (IMFs), energy ratio and power volatility are calculated to detect the unessential components. Meanwhile, combined with vibration function of turbine-grid interaction, data fitting of instantaneous amplitude and phase of each IMF is implemented to extract characteristic parameters of different interactions. Finally, utilizing measured data of actual parallel-operated wind turbines in China, this work accurately obtains the characteristic parameters of turbine-grid interaction of grid-connected wind turbine.

Grid generation methods

CERN Document Server

Liseikin, Vladimir D

2017-01-01

This new edition provides a description of current developments relating to grid methods, grid codes, and their applications to actual problems. Grid generation methods are indispensable for the numerical solution of differential equations. Adaptive grid-mapping techniques, in particular, are the main focus and represent a promising tool to deal with systems with singularities. This 3rd edition includes three new chapters on numerical implementations (10), control of grid properties (11), and applications to mechanical, fluid, and plasma related problems (13). Also the other chapters have been updated including new topics, such as curvatures of discrete surfaces (3). Concise descriptions of hybrid mesh generation, drag and sweeping methods, parallel algorithms for mesh generation have been included too. This new edition addresses a broad range of readers: students, researchers, and practitioners in applied mathematics, mechanics, engineering, physics and other areas of applications.

A Framework for Counterfeit Smart Grid Device Detection

Energy Technology Data Exchange (ETDEWEB)

Babun, Leonardo [Florida Intl Univ., Miami, FL (United States); Aksu, Hidayet [Florida Intl Univ., Miami, FL (United States); Uluagac, A. Selcuk [Florida Intl Univ., Miami, FL (United States)

2016-10-19

The core vision of the smart grid concept is the realization of reliable two-­way communications between smart devices (e.g., IEDs, PLCs, PMUs). The benefits of the smart grid also come with tremendous security risks and new challenges in protecting the smart grid systems from cyber threats. Particularly, the use of untrusted counterfeit smart grid devices represents a real problem. Consequences of propagating false or malicious data, as well as stealing valuable user or smart grid state information from counterfeit devices are costly. Hence, early detection of counterfeit devices is critical for protecting smart grid’s components and users. To address these concerns, in this poster, we introduce our initial design of a configurable framework that utilize system call tracing, library interposition, and statistical techniques for monitoring and detection of counterfeit smart grid devices. In our framework, we consider six different counterfeit device scenarios with different smart grid devices and adversarial seZings. Our initial results on a realistic testbed utilizing actual smart-­grid GOOSE messages with IEC-­61850 communication protocol are very promising. Our framework is showing excellent rates on detection of smart grid counterfeit devices from impostors.

Evaluation of load flow and grid expansion in a unit-commitment and expansion optimization model SciGRID International Conference on Power Grid Modelling

Science.gov (United States)

Senkpiel, Charlotte; Biener, Wolfgang; Shammugam, Shivenes; Längle, Sven

2018-02-01

Energy system models serve as a basis for long term system planning. Joint optimization of electricity generating technologies, storage systems and the electricity grid leads to lower total system cost compared to an approach in which the grid expansion follows a given technology portfolio and their distribution. Modelers often face the problem of finding a good tradeoff between computational time and the level of detail that can be modeled. This paper analyses the differences between a transport model and a DC load flow model to evaluate the validity of using a simple but faster transport model within the system optimization model in terms of system reliability. The main findings in this paper are that a higher regional resolution of a system leads to better results compared to an approach in which regions are clustered as more overloads can be detected. An aggregation of lines between two model regions compared to a line sharp representation has little influence on grid expansion within a system optimizer. In a DC load flow model overloads can be detected in a line sharp case, which is therefore preferred. Overall the regions that need to reinforce the grid are identified within the system optimizer. Finally the paper recommends the usage of a load-flow model to test the validity of the model results.

Desain Pengisian Optimal Kendaraan Listrik Berdasarkan Kebutuhan Daya Grid dan Kondisi Grid pada Stasiun Pengisian Kendaraan Listrik Menggunakan Kontroler Logika Fuzzy

Directory of Open Access Journals (Sweden)

Onang Surya Nugroho

2017-01-01

Full Text Available Electric vehicles has become one of alternatives in addressing energy crisis in the field of transportation. Increasing the number of electric vehicles that are not accompanied by a proper charging station management would give negative impact either to the distribution system on the network such as voltage fluctuation, voltage drop, voltage stress, lack of continuity of the power system, and even cause the blackout. Energy management design is needed for electric vehicles charging stations to obtain optimal power flow model between charging station and grid. This research will be designed an analysis and design of optimal charging by considering estimated power flow between charging station with the grid and load conditions on the grid (off-peak / peak using fuzzy logic controller. This charging management uses the concept vehicle to vehicle (V2V, vehicle to grid (V2G, and the grid to vehicle (G2V which adjust by charging index and charging rate results from rule fuzzy scoring result. The simulation results show that the fuzzy-based system can flatten the load curve peak of electric vehicle, reducing the impact of peak load to the grid, and can provide cost advantages in the form of cost saving.

Grid sleeve bulge tool

International Nuclear Information System (INIS)

Phillips, W.D.; Vaill, R.E.

1980-01-01

An improved grid sleeve bulge tool is designed for securing control rod guide tubes to sleeves brazed in a fuel assembly grid. The tool includes a cylinder having an outer diameter less than the internal diameter of the control rod guide tubes. The walls of the cylinder are cut in an axial direction along its length to provide several flexible tines or ligaments. These tines are similar to a fork except they are spaced in a circumferential direction. The end of each alternate tine is equipped with a semispherical projection which extends radially outwardly from the tine surface. A ram or plunger of generally cylindrical configuration and about the same length as the cylinder is designed to fit in and move axially of the cylinder and thereby force the tined projections outwardly when the ram is pulled into the cylinder. The ram surface includes axially extending grooves and plane surfaces which are complimentary to the inner surfaces formed on the tines on the cylinder. As the cylinder is inserted into a control rod guide tube, and the projections on the cylinder placed in a position just below or above a grid strap, the ram is pulled into the cylinder, thus moving the tines and the projections thereon outwardly into contact with the sleeve, to plastically deform both the sleeve and the control rod guide tube, and thereby form four bulges which extend outwardly from the sleeve surface and beyond the outer periphery of the grid peripheral strap. This process is then repeated at the points above the grid to also provide for outwardly projecting surfaces, the result being that the grid is accurately positioned on and mechanically secured to the control rod guide tubes which extend the length of a fuel assembly

Reliability analysis in interdependent smart grid systems

Science.gov (United States)

Peng, Hao; Kan, Zhe; Zhao, Dandan; Han, Jianmin; Lu, Jianfeng; Hu, Zhaolong

2018-06-01

Complex network theory is a useful way to study many real complex systems. In this paper, a reliability analysis model based on complex network theory is introduced in interdependent smart grid systems. In this paper, we focus on understanding the structure of smart grid systems and studying the underlying network model, their interactions, and relationships and how cascading failures occur in the interdependent smart grid systems. We propose a practical model for interdependent smart grid systems using complex theory. Besides, based on percolation theory, we also study the effect of cascading failures effect and reveal detailed mathematical analysis of failure propagation in such systems. We analyze the reliability of our proposed model caused by random attacks or failures by calculating the size of giant functioning components in interdependent smart grid systems. Our simulation results also show that there exists a threshold for the proportion of faulty nodes, beyond which the smart grid systems collapse. Also we determine the critical values for different system parameters. In this way, the reliability analysis model based on complex network theory can be effectively utilized for anti-attack and protection purposes in interdependent smart grid systems.

Insurance premiums and insurance coverage of near-poor children.

Science.gov (United States)

Hadley, Jack; Reschovsky, James D; Cunningham, Peter; Kenney, Genevieve; Dubay, Lisa

States increasingly are using premiums for near-poor children in their public insurance programs (Medicaid/SCHIP) to limit private insurance crowd-out and constrain program costs. Using national data from four rounds of the Community Tracking Study Household Surveys spanning the seven years from 1996 to 2003, this study estimates a multinomial logistic regression model examining how public and private insurance premiums affect insurance coverage outcomes (Medicaid/SCHIP coverage, private coverage, and no coverage). Higher public premiums are significantly associated with a lower probability of public coverage and higher probabilities of private coverage and uninsurance; higher private premiums are significantly related to a lower probability of private coverage and higher probabilities of public coverage and uninsurance. The results imply that uninsurance rates will rise if both public and private premiums increase, and suggest that states that impose or increase public insurance premiums for near-poor children will succeed in discouraging crowd-out of private insurance, but at the expense of higher rates of uninsurance. Sustained increases in private insurance premiums will continue to create enrollment pressures on state insurance programs for children.

Optimal moving grids for time-dependent partial differential equations

Science.gov (United States)

Wathen, A. J.

1992-01-01

Various adaptive moving grid techniques for the numerical solution of time-dependent partial differential equations were proposed. The precise criterion for grid motion varies, but most techniques will attempt to give grids on which the solution of the partial differential equation can be well represented. Moving grids are investigated on which the solutions of the linear heat conduction and viscous Burgers' equation in one space dimension are optimally approximated. Precisely, the results of numerical calculations of optimal moving grids for piecewise linear finite element approximation of PDE solutions in the least-squares norm are reported.

Conducted Electromagnetic Interference (EMI) in Smart Grids

CERN Document Server

Smolenski, Robert

2012-01-01

As power systems develop to incorporate renewable energy sources, the delivery systems may be disrupted by the changes involved. The grid’s technology and management must be developed to form Smart Grids between consumers, suppliers and producers. Conducted Electromagnetic Interference (EMI) in Smart Grids considers the specific side effects related to electromagnetic interference (EMI) generated by the application of these Smart Grids. Conducted Electromagnetic Interference (EMI) in Smart Grids presents specific EMI conducted phenomena as well as effective methods to filter and handle them once identified. After introduction to Smart Grids, the following sections cover dedicated methods for EMI reduction and potential avenues for future development including chapters dedicated to: •potential system services, •descriptions of the EMI spectra shaping methods, •methods of interference voltage compensation, and theoretical analysis of experimental results.  By focusing on these key aspects, Conducted El...

Beyond grid security

International Nuclear Information System (INIS)

Hoeft, B; Epting, U; Koenig, T

2008-01-01

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

Results from Evaluations of Gridded CrIS/ATMS Visualization for Operational Forecasting

Science.gov (United States)

Stevens, E.; Zavodsky, B.; Dostalek, J.; Berndt, E.; Hoese, D.; White, K.; Bowlan, M.; Gambacorta, A.; Wheeler, A.; Haisley, C.; Smith, N.

2017-12-01

For forecast challenges which require diagnosis of the three-dimensional atmosphere, current observations, such as radiosondes, may not offer enough information. Satellite data can help fill the spatial and temporal gaps between soundings. In particular, temperature and moisture retrievals from the NOAA-Unique Combined Atmospheric Processing System (NUCAPS), which combines infrared soundings from the Cross-track Infrared Sounder (CrIS) with the Advanced Technology Microwave Sounder (ATMS) to retrieve profiles of temperature and moisture. NUCAPS retrievals are available in a wide swath with approximately 45-km spatial resolution at nadir and a local Equator crossing time of 1:30 A.M./P.M. enabling three-dimensional observations at asynoptic times. This abstract focuses on evaluation of a new visualization for NUCAPS within the operational National Weather Service Advanced Weather Interactive Processing System (AWIPS) decision support system that allows these data to be viewed in gridded horizontal maps or vertical cross sections. Two testbed evaluations have occurred in 2017: a Cold Air Aloft (CAA) evaluation at the Alaska Center Weather Service Unit and a Convective Potential evaluation at the NOAA Hazardous Weather Testbed. For CAA, at high latitudes during the winter months, the air at altitudes used by passenger and cargo aircraft can reach temperatures cold enough (-65°C) to begin to freeze jet fuel, and Gridded NUCAPS visualization was shown to help fill in the spatial and temporal gaps in data-sparse areas across the Alaskan airspace by identifying the 3D spatial extent of cold air features. For convective potential, understanding the vertical distribution of temperature and moisture is also very important for forecasting the potential for convection related to severe weather such as lightning, large hail, and tornadoes. The Gridded NUCAPS visualization was shown to aid forecasters in understanding temperature and moisture characteristics at critical levels

Grid Frequency Extreme Event Analysis and Modeling: Preprint

Energy Technology Data Exchange (ETDEWEB)

Florita, Anthony R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Clark, Kara [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Gevorgian, Vahan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Folgueras, Maria [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wenger, Erin [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-11-01

Sudden losses of generation or load can lead to instantaneous changes in electric grid frequency and voltage. Extreme frequency events pose a major threat to grid stability. As renewable energy sources supply power to grids in increasing proportions, it becomes increasingly important to examine when and why extreme events occur to prevent destabilization of the grid. To better understand frequency events, including extrema, historic data were analyzed to fit probability distribution functions to various frequency metrics. Results showed that a standard Cauchy distribution fit the difference between the frequency nadir and prefault frequency (f_(C-A)) metric well, a standard Cauchy distribution fit the settling frequency (f_B) metric well, and a standard normal distribution fit the difference between the settling frequency and frequency nadir (f_(B-C)) metric very well. Results were inconclusive for the frequency nadir (f_C) metric, meaning it likely has a more complex distribution than those tested. This probabilistic modeling should facilitate more realistic modeling of grid faults.

Power grid complex network evolutions for the smart grid

NARCIS (Netherlands)

Pagani, Giuliano Andrea; Aiello, Marco

2014-01-01

The shift towards an energy grid dominated by prosumers (consumers and producers of energy) will inevitably have repercussions on the electricity distribution infrastructure. Today the grid is a hierarchical one delivering energy from large scale facilities to end-users. Tomorrow it will be a

Demand response evaluation and forecasting — Methods and results from the EcoGrid EU experiment

DEFF Research Database (Denmark)

Larsen, Emil Mahler; Pinson, Pierre; Leimgruber, Fabian

2017-01-01

Understanding electricity consumers participating in new demand response schemes is important for investment decisions and the design and operation of electricity markets. Important metrics include peak response, time to peak response, energy delivered, ramping, and how the response changes...... with respect to external conditions. Such characteristics dictate the services DR is capable of offering, like primary frequency reserves, peak load shaving, and system balancing. In this paper, we develop methods to characterise price-responsive demand from the EcoGrid EU demonstration in a way that was bid...... into a real-time market. EcoGrid EU is a smart grid experiment with 1900 residential customers who are equipped with smart meters and automated devices reacting to five-minute electricity pricing. Customers are grouped and analysed according to the manufacturer that controlled devices. A number of advanced...

National power grid simulation capability : need and issues

Energy Technology Data Exchange (ETDEWEB)

Petri, Mark C. [Argonne National Lab. (ANL), Argonne, IL (United States)

2009-06-02

On December 9 and 10, 2008, the Department of Homeland Security (DHS) Science and Technology Directorate sponsored a national workshop at Argonne National Laboratory to explore the need for a comprehensive modeling and simulation capability for the national electric power grid system. The workshop brought together leading electric power grid experts from federal agencies, the national laboratories, and academia to discuss the current state of power grid science and engineering and to assess if important challenges are being met. The workshop helped delineate gaps between grid needs and current capabilities and identify issues that must be addressed if a solution is to be implemented. This report is a result of the workshop and highlights power grid modeling and simulation needs, the barriers that must be overcome to address them, and the benefits of a national power grid simulation capability.

Smart Grid Information Clearinghouse (SGIC)

Energy Technology Data Exchange (ETDEWEB)

Rahman, Saifur [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

2014-08-31

Since the Energy Independence and Security Act of 2007 was enacted, there has been a large number of websites that discusses smart grid and relevant information, including those from government, academia, industry, private sector and regulatory. These websites collect information independently. Therefore, smart grid information was quite scattered and dispersed. The objective of this work was to develop, populate, manage and maintain the public Smart Grid Information Clearinghouse (SGIC) web portal. The information in the SGIC website is comprehensive that includes smart grid information, research & development, demonstration projects, technical standards, costs & benefit analyses, business cases, legislation, policy & regulation, and other information on lesson learned and best practices. The content in the SGIC website is logically grouped to allow easily browse, search and sort. In addition to providing the browse and search feature, the SGIC web portal also allow users to share their smart grid information with others though our online content submission platform. The Clearinghouse web portal, therefore, serves as the first stop shop for smart grid information that collects smart grid information in a non-bias, non-promotional manner and can provide a missing link from information sources to end users and better serve users’ needs. The web portal is available at www.sgiclearinghouse.org. This report summarizes the work performed during the course of the project (September 2009 – August 2014). Section 2.0 lists SGIC Advisory Committee and User Group members. Section 3.0 discusses SGIC information architecture and web-based database application functionalities. Section 4.0 summarizes SGIC features and functionalities, including its search, browse and sort capabilities, web portal social networking, online content submission platform and security measures implemented. Section 5.0 discusses SGIC web portal contents, including smart grid 101, smart grid projects

Socioeconomic assessment of smart grids. Summary

International Nuclear Information System (INIS)

2015-07-01

range of regional situations and advanced functions to yield an initial estimate of the gains their deployment could generate, and made it possible to start ranking the solutions based on their potential economic viability. On the other hand, the methodologies, scopes of evaluation and hypotheses applied were not uniform. Indeed, each demonstration project tested and assessed one or more smart grid solutions applying specific objectives and evaluation methods. As a result, they could not be used to compare the benefits of different advanced functions. The methodology defined under action item 5 in the 'Smart Grids' plan, and the related assessments, should make it possible to better identify the solutions that offer the highest returns for the community and thus enable a targeted and streamlined deployment of smart grid solutions. This document summarises the conclusions drawn under action item 5 in the 'Smart Grids' plan

Socioeconomic assessment of smart grids - Summary

International Nuclear Information System (INIS)

Janssen, Tanguy

2015-07-01

range of regional situations and advanced functions to yield an initial estimate of the gains their deployment could generate, and made it possible to start ranking the solutions based on their potential economic viability. On the other hand, the methodologies, scopes of evaluation and hypotheses applied were not uniform. Indeed, each demonstration project tested and assessed one or more smart grid solutions applying specific objectives and evaluation methods. As a result, they could not be used to compare the benefits of different advanced functions. The methodology defined under action item 5 in the 'Smart Grids' plan, and the related assessments, should make it possible to better identify the solutions that offer the highest returns for the community and thus enable a targeted and streamlined deployment of smart grid solutions. This document details the conclusions drawn under action item 5 in the 'Smart Grids' plan

Grid interoperability: the interoperations cookbook

Energy Technology Data Exchange (ETDEWEB)

Field, L; Schulz, M [CERN (Switzerland)], E-mail: Laurence.Field@cern.ch, E-mail: Markus.Schulz@cern.ch

2008-07-01

Over recent years a number of grid projects have emerged which have built grid infrastructures that are now the computing backbones for various user communities. A significant number of these communities are limited to one grid infrastructure due to the different middleware and procedures used in each grid. Grid interoperation is trying to bridge these differences and enable virtual organizations to access resources independent of the grid project affiliation. This paper gives an overview of grid interoperation and describes the current methods used to bridge the differences between grids. Actual use cases encountered during the last three years are discussed and the most important interfaces required for interoperability are highlighted. A summary of the standardisation efforts in these areas is given and we argue for moving more aggressively towards standards.

Grid interoperability: the interoperations cookbook

International Nuclear Information System (INIS)

Field, L; Schulz, M

2008-01-01

Over recent years a number of grid projects have emerged which have built grid infrastructures that are now the computing backbones for various user communities. A significant number of these communities are limited to one grid infrastructure due to the different middleware and procedures used in each grid. Grid interoperation is trying to bridge these differences and enable virtual organizations to access resources independent of the grid project affiliation. This paper gives an overview of grid interoperation and describes the current methods used to bridge the differences between grids. Actual use cases encountered during the last three years are discussed and the most important interfaces required for interoperability are highlighted. A summary of the standardisation efforts in these areas is given and we argue for moving more aggressively towards standards

Improved control strategy for the three-phase grid-connected inverter

DEFF Research Database (Denmark)

Yao, Zhilei; Xiao, Lan; Guerrero, Josep M.

2015-01-01

An improved control strategy for the three-phase grid-connected inverter with space vector pulse width modulation (SVPWM) is proposed. When the grid current contains harmonics, the d- and q-axis grid currents will be interacted, and then the waveform quality of the grid current will be poorer....... As the reference output voltage cannot directly reflect the change of the reference grid current, the dynamic response of the grid-connected inverter is slow. In order to solve the aforementioned problems, the d- and q-axis grid currents in the decoupled components of the grid current controller can be substituted...... by the d- and q-axis reference grid currents, respectively. The operating principles of the traditional and proposed control methods are illustrated. Experimental results for a 15-kVA three-phase grid-connected inverter with SVPWM verify the theoretical analysis. Compared with the traditional control...

Grid Security

CERN Multimedia

CERN. Geneva

2004-01-01

The aim of Grid computing is to enable the easy and open sharing of resources between large and highly distributed communities of scientists and institutes across many independent administrative domains. Convincing site security officers and computer centre managers to allow this to happen in view of today's ever-increasing Internet security problems is a major challenge. Convincing users and application developers to take security seriously is equally difficult. This paper will describe the main Grid security issues, both in terms of technology and policy, that have been tackled over recent years in LCG and related Grid projects. Achievements to date will be described and opportunities for future improvements will be addressed.

Emissions & Generation Resource Integrated Database (eGRID), eGRID2012

Data.gov (United States)

U.S. Environmental Protection Agency — The Emissions emissions rates; net generation; resource mix; and many other attributes. eGRID2012 Version 1.0 is the eighth edition of eGRID, which contains the...

Integrated Multi-Scale Data Analytics and Machine Learning for the Distribution Grid and Building-to-Grid Interface

Energy Technology Data Exchange (ETDEWEB)

Stewart, Emma M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Hendrix, Val [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chertkov, Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Deka, Deepjyoti [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-03-16

This white paper introduces the application of advanced data analytics to the modernized grid. In particular, we consider the field of machine learning and where it is both useful, and not useful, for the particular field of the distribution grid and buildings interface. While analytics, in general, is a growing field of interest, and often seen as the golden goose in the burgeoning distribution grid industry, its application is often limited by communications infrastructure, or lack of a focused technical application. Overall, the linkage of analytics to purposeful application in the grid space has been limited. In this paper we consider the field of machine learning as a subset of analytical techniques, and discuss its ability and limitations to enable the future distribution grid and the building-to-grid interface. To that end, we also consider the potential for mixing distributed and centralized analytics and the pros and cons of these approaches. Machine learning is a subfield of computer science that studies and constructs algorithms that can learn from data and make predictions and improve forecasts. Incorporation of machine learning in grid monitoring and analysis tools may have the potential to solve data and operational challenges that result from increasing penetration of distributed and behind-the-meter energy resources. There is an exponentially expanding volume of measured data being generated on the distribution grid, which, with appropriate application of analytics, may be transformed into intelligible, actionable information that can be provided to the right actors – such as grid and building operators, at the appropriate time to enhance grid or building resilience, efficiency, and operations against various metrics or goals – such as total carbon reduction or other economic benefit to customers. While some basic analysis into these data streams can provide a wealth of information, computational and human boundaries on performing the analysis

Integrating renewables in distribution grids. Storage, regulation and the interaction of different stakeholders in future grids

Energy Technology Data Exchange (ETDEWEB)

Nykamp, S.

2013-10-18

In recent years, the transition of the power supply chain towards a sustainable system based on 'green' electricity generation out of renewable energy sources (RES-E) has become a main challenge for grid operators and further stakeholders in the power system. To enable the evaluation of new concepts for the integration of RES-E, first the feed-in characteristics of photovoltaic, wind and biomass generators located in a distribution grid area and based on numerous measured feed-in data are studied in this thesis. The achieved insights from the feed-in profiles can be used for the dimensioning of grid assets. Furthermore, the results are useful for the evaluation of congestion management or for the dimensioning of storage assets in distribution grids. The latter aspect is analyzed in detail such that suitable storage characteristics for an introduction in the grid are determined. An economic approach is presented to derive break-even points for storage assets as a substitute to conventional reinforcements. For a case study from a real world low voltage grid with reinforcement needs, these break-even points are determined and the main influencing parameters are evaluated. A further important question in this context concerns the role DSOs (distribution system operators) may play with the operation of decentralized storage assets since several stakeholders may be interested in using the flexibility provided by these assets. This unclear responsibility also applies to the steering of adjustable consumption devices such as electric heat pumps or electric cars. For decentralized storage assets as well as heat pump appliances, optimal operation modes based on the optimization objectives for a DSO and a trader are derived. It is shown based on real world data that choosing a 'copperplate' scenario is not only technically insufficient for a global balance of the consumption and generation. It may even be harmful for the society from a welfare economic

Resistance Fluctuations in GaAs Nanowire Grids

Directory of Open Access Journals (Sweden)

Ivan Marasović

2014-01-01

Full Text Available We present a numerical study on resistance fluctuations in a series of nanowire-based grids. Each grid is made of GaAs nanowires arranged in parallel with metallic contacts crossing all nanowires perpendicularly. Electrical properties of GaAs nanowires known from previous experimental research are used as input parameters in the simulation procedure. Due to the nonhomogeneous doping, the resistivity changes along nanowire. Allowing two possible nanowire orientations (“upwards” or “downwards”, the resulting grid is partially disordered in vertical direction which causes resistance fluctuations. The system is modeled using a two-dimensional random resistor network. Transfer-matrix computation algorithm is used to calculate the total network resistance. It is found that probability density function (PDF of resistance fluctuations for a series of nanowire grids changes from Gaussian behavior towards the Bramwell-Holdsworth-Pinton distribution when both nanowire orientations are equally represented in the grid.

Adaptive grid generation in a patient-specific cerebral aneurysm

Science.gov (United States)

Hodis, Simona; Kallmes, David F.; Dragomir-Daescu, Dan

2013-11-01

Adapting grid density to flow behavior provides the advantage of increasing solution accuracy while decreasing the number of grid elements in the simulation domain, therefore reducing the computational time. One method for grid adaptation requires successive refinement of grid density based on observed solution behavior until the numerical errors between successive grids are negligible. However, such an approach is time consuming and it is often neglected by the researchers. We present a technique to calculate the grid size distribution of an adaptive grid for computational fluid dynamics (CFD) simulations in a complex cerebral aneurysm geometry based on the kinematic curvature and torsion calculated from the velocity field. The relationship between the kinematic characteristics of the flow and the element size of the adaptive grid leads to a mathematical equation to calculate the grid size in different regions of the flow. The adaptive grid density is obtained such that it captures the more complex details of the flow with locally smaller grid size, while less complex flow characteristics are calculated on locally larger grid size. The current study shows that kinematic curvature and torsion calculated from the velocity field in a cerebral aneurysm can be used to find the locations of complex flow where the computational grid needs to be refined in order to obtain an accurate solution. We found that the complexity of the flow can be adequately described by velocity and vorticity and the angle between the two vectors. For example, inside the aneurysm bleb, at the bifurcation, and at the major arterial turns the element size in the lumen needs to be less than 10% of the artery radius, while at the boundary layer, the element size should be smaller than 1% of the artery radius, for accurate results within a 0.5% relative approximation error. This technique of quantifying flow complexity and adaptive remeshing has the potential to improve results accuracy and reduce

Grid Cell Relaxation Effects on the High Frequency Vibration Characteristics

International Nuclear Information System (INIS)

Ryu, Joo-Young; Eom, Kyong-Bo; Jeon, Sang-Youn; Kim, Jae-Ik

2015-01-01

The plate structure of the grid of fuel assembly is always exposed to serious vortex induced vibration. Also, High Frequency flow induced Vibration (HFV) is primarily generated by vortex-shedding effect. When it comes to grid design as a fuel assembly component, HFV should be considered in advance since it is one of the critical factors. Excessive HFV has a possibility of making degradation of the fuel reliability that is directly related to the fuel robustness and operating performance. KEPCO NF (KNF) has performed HFV tests with various grid designs. While studying the HFV characteristics through the HFV tests, it has been observed that HFV amplitudes show different levels according to grid cell relaxation. It means that the testing could give different interpretations due to the condition of grid cell. Since the amount of relaxation is different under operating conditions and environments in a reactor, test specimens should be modified as much as possible to the real state of the fuel. Therefore, in order to consider the grid cell relaxation effects on the HFV tests, it is important to use cell sized or non-cell sized grids. The main focus of this study is to find out how the HFV characteristics such as amplitude and frequency are affected by grid cell relaxation. Three cases of the grid cell sized specimen which is nickel alloy were prepared and tested. Through the comparison of the test results, it could be concluded that HFV amplitudes show decreasing trend according to the grid cell relaxation in the case of nickel alloy grid. It is also possible to expect the tendency of grid cell relaxation of a zirconium alloy grid based on test results

The smart grid research network: Road map for Smart Grid research, development and demonstration up to 2020

Energy Technology Data Exchange (ETDEWEB)

Troi, A. [Technical Univ. of Denmark. DTU Electrical Engineering, DTU Risoe Campus, Roskilde (Denmark); Noerregaard Joergensen, B. [Syddansk Univ. (SDU), Odense (Denmark); Mahler Larsen, E. [Technical Univ. of Denmark. DTU Electrical Engineering, Kgs. Lyngby (Denmark)] [and others

2013-01-15

This road map is a result of part-recommendation no. 25 in 'MAIN REPORT - The Smart Grid Network's recommendations', written by the Smart Grid Network for the Danish Ministry of Climate, Energy and Building in October 2011. This part-recommendation states: ''Part-recommendation 25 - A road map for Smart Grid research, development and demonstration It is recommended that the electricity sector invite the Ministry to participate in the creation of a road map to ensure that solutions are implemented and coordinated with related policy areas. The sector should also establish a fast-acting working group with representatives from universities, distribution companies and the electric industry, in order to produce a mutual, binding schedule for the RDD of the Smart Grid in Denmark. Time prioritisation of part-recommendation: 2011-2012 Responsibility for implementation of part-recommendation: Universities, along with relevant electric-industry actors, should establish a working group for the completion of a consolidated road map by the end of 2012.'' In its work on this report, the Smart Grid Research Network has focused particularly on part-recommendations 26, 27 and 28 in 'MAIN REPORT - The Smart Grid Network's recommendations', which relate to strengthening and marketing the research infrastructure that will position Denmark as the global hub for Smart Grid development; strengthening basic research into the complex relationships in electric systems with large quantities of independent parties; and improved understanding of consumer behaviour and social economics. Naturally the work has spread to related areas along the way. The work has been conducted by the Smart Grid Research Network. (Author)

LHC computing grid

International Nuclear Information System (INIS)

Novaes, Sergio

2011-01-01

Full text: We give an overview of the grid computing initiatives in the Americas. High-Energy Physics has played a very important role in the development of grid computing in the world and in Latin America it has not been different. Lately, the grid concept has expanded its reach across all branches of e-Science, and we have witnessed the birth of the first nationwide infrastructures and its use in the private sector. (author)

High density grids

Energy Technology Data Exchange (ETDEWEB)

Cohen, Aina E.; Baxter, Elizabeth L.

2018-01-16

An X-ray data collection grid device is provided that includes a magnetic base that is compatible with robotic sample mounting systems used at synchrotron beamlines, a grid element fixedly attached to the magnetic base, where the grid element includes at least one sealable sample window disposed through a planar synchrotron-compatible material, where the planar synchrotron-compatible material includes at least one automated X-ray positioning and fluid handling robot fiducial mark.

Results from the Operational Testing of the Eaton Smart Grid Capable Electric Vehicle Supply Equipment

Energy Technology Data Exchange (ETDEWEB)

Bennett, Brion [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2014-10-01

The Idaho National Laboratory conducted testing and analysis of the Eaton smart grid capable electric vehicle supply equipment (EVSE), which was a deliverable from Eaton for the U.S. Department of Energy FOA-554. The Idaho National Laboratory has extensive knowledge and experience in testing advanced conductive and wireless charging systems though INL’s support of the U.S. Department of Energy’s Advanced Vehicle Testing Activity. This document details the findings from the EVSE operational testing conducted at the Idaho National Laboratory on the Eaton smart grid capable EVSE. The testing conducted on the EVSE included energy efficiency testing, SAE J1772 functionality testing, abnormal conditions testing, and charging of a plug-in vehicle.

Global Time Tomography of Finite Frequency Waves with Optimized Tetrahedral Grids.

Science.gov (United States)

Montelli, R.; Montelli, R.; Nolet, G.; Dahlen, F. A.; Masters, G.; Hung, S.

2001-12-01

Besides true velocity heterogeneities, tomographic images reflect the effect of data errors, model parametrization, linearization, uncertainties involved with the solution of the forward problem and the greatly inadequate sampling of the earth by seismic rays. These influences cannot be easily separated and often produce artefacts in the final image with amplitudes comparable to those of the velocity heterogeneities. In practice, the tomographer uses some form of damping of the ill-resolved aspects of the model to get a unique solution and reduce the influence of the errors. However damping is not fully adequate, and may reveal a strong influence of the ray path coverage in tomographic images. If some cells are ill determinated regularization techniques may lead to heterogeneity because these cells are damped towards zero. Thus we want a uniform resolution of the parameters in our model. This can be obtained by using an irregular grid with variable length scales. We have introduced an irregular parametrization of the velocity structure by using a Delaunay triangulation. Extensively work on error analysis of tomographic images together with mesh optimization has shown that both resolution and ray density can provide the critical informations needed to re-design grids. However, criteria based on resolution are preferred in the presence of narrow ray beams coming from the same direction. This can be understood if we realise that resolution is not only determined by the number of rays crossing a region, but also by their azimutal coverage. We shall discuss various strategies for grid optimization. In general the computation of the travel times is restricted to ray theory, the infinite frequency approximation of the elastodynamic equation of motion. This simplifies the mathematic and is therefore widely applied in seismic tomography. But ray theory does not account for scattering, wavefront healing and other diffraction effects that render the traveltime of a finite

Framing the grid: effect of boundaries on grid cells and navigation.

Science.gov (United States)

Krupic, Julija; Bauza, Marius; Burton, Stephen; O'Keefe, John

2016-11-15

Cells in the mammalian hippocampal formation subserve neuronal representations of environmental location and support navigation in familiar environments. Grid cells constitute one of the main cell types in the hippocampal formation and are widely believed to represent a universal metric of space independent of external stimuli. Recent evidence showing that grid symmetry is distorted in non-symmetrical environments suggests that a re-examination of this hypothesis is warranted. In this review we will discuss behavioural and physiological evidence for how environmental shape and in particular enclosure boundaries influence grid cell firing properties. We propose that grid cells encode the geometric layout of enclosures. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

The Smart Grid Impact on the Danish DSOs’ Business Model

DEFF Research Database (Denmark)

Ma, Zheng; Sommer, Simon; Jørgensen, Bo Nørregaard

2016-01-01

The transformation progress of the smart grid challenges the market players' business models. One of those market players is the Distribution System Operators (DSOs). This paper aims to elaborate how smart grid influences the DSOs' business models with case studies of two Danish DSOs — Energi......Fyn and TREFOR. The main findings indicate that the Danish smart grid transformation process influences the Danish DSOs' business models via four smart grid related factors: (1) smart meters, (2) Distributed Energy Resources (DERs), (3) Bidirectional electricity flow, and (4) R&D. Therefore, the results show...... that the smart grid incrementally not revolutionary influences the Danish DSOs' business models, and the smart grid transformation of the Danish electricity grid is slower than the agenda of the official Danish smart grid development strategy....

The open science grid

International Nuclear Information System (INIS)

Pordes, R.

2004-01-01

The U.S. LHC Tier-1 and Tier-2 laboratories and universities are developing production Grids to support LHC applications running across a worldwide Grid computing system. Together with partners in computer science, physics grid projects and active experiments, we will build a common national production grid infrastructure which is open in its architecture, implementation and use. The Open Science Grid (OSG) model builds upon the successful approach of last year's joint Grid2003 project. The Grid3 shared infrastructure has for over eight months provided significant computational resources and throughput to a range of applications, including ATLAS and CMS data challenges, SDSS, LIGO, and biology analyses, and computer science demonstrators and experiments. To move towards LHC-scale data management, access and analysis capabilities, we must increase the scale, services, and sustainability of the current infrastructure by an order of magnitude or more. Thus, we must achieve a significant upgrade in its functionalities and technologies. The initial OSG partners will build upon a fully usable, sustainable and robust grid. Initial partners include the US LHC collaborations, DOE and NSF Laboratories and Universities and Trillium Grid projects. The approach is to federate with other application communities in the U.S. to build a shared infrastructure open to other sciences and capable of being modified and improved to respond to needs of other applications, including CDF, D0, BaBar, and RHIC experiments. We describe the application-driven, engineered services of the OSG, short term plans and status, and the roadmap for a consortium, its partnerships and national focus

Porting of Scientific Applications to Grid Computing on GridWay

Directory of Open Access Journals (Sweden)

J. Herrera

2005-01-01

Full Text Available The expansion and adoption of Grid technologies is prevented by the lack of a standard programming paradigm to port existing applications among different environments. The Distributed Resource Management Application API has been proposed to aid the rapid development and distribution of these applications across different Distributed Resource Management Systems. In this paper we describe an implementation of the DRMAA standard on a Globus-based testbed, and show its suitability to express typical scientific applications, like High-Throughput and Master-Worker applications. The DRMAA routines are supported by the functionality offered by the GridWay2 framework, which provides the runtime mechanisms needed for transparently executing jobs on a dynamic Grid environment based on Globus. As cases of study, we consider the implementation with DRMAA of a bioinformatics application, a genetic algorithm and the NAS Grid Benchmarks.

FermiGrid - experience and future plans

International Nuclear Information System (INIS)

Chadwick, K.; Berman, E.; Canal, P.; Hesselroth, T.; Garzoglio, G.; Levshina, T.; Sergeev, V.; Sfiligoi, I.; Timm, S.; Yocum, D.

2007-01-01

Fermilab supports a scientific program that includes experiments and scientists located across the globe. In order to better serve this community, Fermilab has placed its production computer resources in a Campus Grid infrastructure called 'FermiGrid'. The FermiGrid infrastructure allows the large experiments at Fermilab to have priority access to their own resources, enables sharing of these resources in an opportunistic fashion, and movement of work (jobs, data) between the Campus Grid and National Grids such as Open Science Grid and the WLCG. FermiGrid resources support multiple Virtual Organizations (VOs), including VOs from the Open Science Grid (OSG), EGEE and the Worldwide LHC Computing Grid Collaboration (WLCG). Fermilab also makes leading contributions to the Open Science Grid in the areas of accounting, batch computing, grid security, job management, resource selection, site infrastructure, storage management, and VO services. Through the FermiGrid interfaces, authenticated and authorized VOs and individuals may access our core grid services, the 10,000+ Fermilab resident CPUs, near-petabyte (including CMS) online disk pools and the multi-petabyte Fermilab Mass Storage System. These core grid services include a site wide Globus gatekeeper, VO management services for several VOs, Fermilab site authorization services, grid user mapping services, as well as job accounting and monitoring, resource selection and data movement services. Access to these services is via standard and well-supported grid interfaces. We will report on the user experience of using the FermiGrid campus infrastructure interfaced to a national cyberinfrastructure--the successes and the problems

Smart grid in China

DEFF Research Database (Denmark)

Sommer, Simon; Ma, Zheng; Jørgensen, Bo Nørregaard

2015-01-01

China is planning to transform its traditional power grid in favour of a smart grid, since it allows a more economically efficient and a more environmentally friendly transmission and distribution of electricity. Thus, a nationwide smart grid is likely to save tremendous amounts of resources...

Power-electronic asset characteristics for HVDC-connected offshore grids

Energy Technology Data Exchange (ETDEWEB)

Heising, C.; Meyer, D.; Bartelt, R. [Avasition GmbH, Dortmund (Germany); Koochack Zadeh, M.; Lebioda, T.J.; Jung, J. [TenneT Offshore GmbH, Bayreuth (Germany)

2012-07-01

Analysing offshore wind-farm applications as well as other converter-dominated grids, two key differences can be identified compared to conventional configurations: No relevant short-circuit power is available and no inertia is directly coupled to the AC grid. Within this paper, power-electronic asset characteristics for HVDC-connected offshore grids are presented which apply new principles allowing for better dynamic operation in the weak grids introduced. The capability is demonstrated using simulation results of an AC-multi-terminal system. (orig.)

GRID computing for experimental high energy physics

International Nuclear Information System (INIS)

Moloney, G.R.; Martin, L.; Seviour, E.; Taylor, G.N.; Moorhead, G.F.

2002-01-01

Full text: The Large Hadron Collider (LHC), to be completed at the CERN laboratory in 2006, will generate 11 petabytes of data per year. The processing of this large data stream requires a large, distributed computing infrastructure. A recent innovation in high performance distributed computing, the GRID, has been identified as an important tool in data analysis for the LHC. GRID computing has actual and potential application in many fields which require computationally intensive analysis of large, shared data sets. The Australian experimental High Energy Physics community has formed partnerships with the High Performance Computing community to establish a GRID node at the University of Melbourne. Through Australian membership of the ATLAS experiment at the LHC, Australian researchers have an opportunity to be involved in the European DataGRID project. This presentation will include an introduction to the GRID, and it's application to experimental High Energy Physics. We will present the results of our studies, including participation in the first LHC data challenge

The Hel Peninsula – Smart Grid Pilot Project

Directory of Open Access Journals (Sweden)

Sławomir Noske

2014-12-01

Full Text Available The paper presents the scope and results of engineering, and the scope of Smart Grid deployment in the Hel Peninsula. The following functionalities will be described: Fault Detection, Isolation & Recovery – FDIR function, Integrated Volt/Var Control (IVVC function, advanced supervision of LV grid, including distributed energy resources. The paper contains implementation results and research findings, as well as preliminary cost-benefit analysis of the project. Moreover, since Smart Metering and Smart Grid projects are being deployed in the same region – the Hel Peninisula – the benefit achieved by merging the two projects will be explained.

Grid today, clouds on the horizon

Science.gov (United States)

Shiers, Jamie

2009-04-01

By the time of CCP 2008, the largest scientific machine in the world - the Large Hadron Collider - had been cooled down as scheduled to its operational temperature of below 2 degrees Kelvin and injection tests were starting. Collisions of proton beams at 5+5 TeV were expected within one to two months of the initial tests, with data taking at design energy ( 7+7 TeV) foreseen for 2009. In order to process the data from this world machine, we have put our "Higgs in one basket" - that of Grid computing [The Worldwide LHC Computing Grid (WLCG), in: Proceedings of the Conference on Computational Physics 2006 (CCP 2006), vol. 177, 2007, pp. 219-223]. After many years of preparation, 2008 saw a final "Common Computing Readiness Challenge" (CCRC'08) - aimed at demonstrating full readiness for 2008 data taking, processing and analysis. By definition, this relied on a world-wide production Grid infrastructure. But change - as always - is on the horizon. The current funding model for Grids - which in Europe has been through 3 generations of EGEE projects, together with related projects in other parts of the world, including South America - is evolving towards a long-term, sustainable e-infrastructure, like the European Grid Initiative (EGI) [The European Grid Initiative Design Study, website at http://web.eu-egi.eu/]. At the same time, potentially new paradigms, such as that of "Cloud Computing" are emerging. This paper summarizes the results of CCRC'08 and discusses the potential impact of future Grid funding on both regional and international application communities. It contrasts Grid and Cloud computing models from both technical and sociological points of view. Finally, it discusses the requirements from production application communities, in terms of stability and continuity in the medium to long term.

Maturity grids as tools for change management

DEFF Research Database (Denmark)

Maier, Anja; Moultrie, James; Clarkson, P John

2011-01-01

A maturity grid is a change management tool. Levels of maturity are assigned against aspects of an area under study, thus creating a grid. Text descriptions at the resulting intersections describe the typical behaviour exhibited by a firm for each area under study and from the basis...... for the assessment scale. It is a flexible assessment technique that is used by practitioners in industry, consultants and researchers in academia for diagnostic, reflective and improvement purposes. A large number of maturity grids have been proposed to assess a range of capabilities including quality management...

A Grid Voltage Measurement Method for Wind Power Systems during Grid Fault Conditions

OpenAIRE

Yoo, Cheol-Hee; Chung, Il-Yop; Yoo, Hyun-Jae; Hong, Sung-Soo

2014-01-01

Grid codes in many countries require low-voltage ride-through (LVRT) capability to maintain power system stability and reliability during grid fault conditions. To meet the LVRT requirement, wind power systems must stay connected to the grid and also supply reactive currents to the grid to support the recovery from fault voltages. This paper presents a new fault detection method and inverter control scheme to improve the LVRT capability for full-scale permanent magnet synchronous generator (P...

Parametric analysis of protective grid flow induced vibration

Energy Technology Data Exchange (ETDEWEB)

Ryu, Jooyoung; Eom, Kyongbo; Jeon, Sangyoun; Suh, Jungmin [KEPCO NF Co., Daejeon (Korea, Republic of)

2012-10-15

Protective grid (P-grid) flow-induced vibration in a nuclear power reactor is one of the critical factors for the mechanical integrity of a nuclear fuel. The P-grid is located at the lower most position above the bottom nozzle of the nuclear fuel as shown in Fig. 1, and it is required for not only filtering debris, but also supporting fuel rods. On the other hand, P-grid working conditions installed in a nuclear fuel in a reactor are severe in terms of flow speed, temperature and pressure. Considering such a severe condition of P-grid's functional performance in working environment, excessive vibration could be developed. Furthermore, if the P-grid is exposed to high levels of excessive vibration over a long period of time, fatigue failure could be unavoidable. Therefore, it is important to reduce excessive vibration while maintaining P-grid's own functional performance. KEPCO Nuclear Fuel has developed a test facility - Investigation Flow-induced Vibration (INFINIT) - to study flow-induced vibration caused by flowing coolant at various flow rates. To investigate specific relationships between configuration of P-grid and flow-induced vibration characteristics, several types of the P-grids were tested in INFINIT facility. And, based on the test results through parametric studies, the flow-induced vibration characteristics could be analyzed, and critical design parameters were found.

Comprehensive Smart Grid Planning in a Regulated Utility Environment

Science.gov (United States)

Turner, Matthew; Liao, Yuan; Du, Yan

2015-06-01

This paper presents the tools and exercises used during the Kentucky Smart Grid Roadmap Initiative in a collaborative electric grid planning process involving state regulators, public utilities, academic institutions, and private interest groups. The mandate of the initiative was to assess the existing condition of smart grid deployments in Kentucky, to enhance understanding of smart grid concepts by stakeholders, and to develop a roadmap for the deployment of smart grid technologies by the jurisdictional utilities of Kentucky. Through involvement of many important stakeholder groups, the resultant Smart Grid Deployment Roadmap proposes an aggressive yet achievable strategy and timetable designed to promote enhanced availability, security, efficiency, reliability, affordability, sustainability and safety of the electricity supply throughout the state while maintaining Kentucky's nationally competitive electricity rates. The models and methods developed for this exercise can be utilized as a systematic process for the planning of coordinated smart grid deployments.

Smart-grid investments, regulation and organization

International Nuclear Information System (INIS)

Agrell, Per J.; Bogetoft, Peter; Mikkers, Misja

2013-01-01

Grid infrastructure managers worldwide are facing demands for reinvestments in new assets with higher on-grid and off-grid functionality in order to meet new environmental targets. The roles of the current actors will change as the vertical interfaces between regulated and unregulated tasks become blurred. In this paper, we characterize some of the effects of new asset investments policy on the network tasks, assets and costs and contrast this with the assumptions of the current economic network regulation. To provide structure, we present a model of investment provision under regulation between a distribution system operator and a potential investor–generator. The results from the model confirm the hypothesis that network regulation should find a focal point, should integrate externalities in the performance assessment and should avoid wide delegation of contracting-billing for smart-grid investments. - Highlights: ► We review regulatory solutions for smart-grid and DER investments. ► What matters more than upfront incentives is organization and delegation. ► We model regulated investment under private information by a generator or a DSO. ► Highest welfare for high-powered incentives and centralized information. ► Market approaches likely to give poor outcomes for this case.

Benchmarking of Grid Fault Modes in Single-Phase Grid-Connected Photovoltaic Systems

DEFF Research Database (Denmark)

Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang

2013-01-01

Pushed by the booming installations of singlephase photovoltaic (PV) systems, the grid demands regarding the integration of PV systems are expected to be modified. Hence, the future PV systems should become more active with functionalities of Low Voltage Ride-Through (LVRT) and grid support...... phase systems under grid faults. The intent of this paper is to present a benchmarking of grid fault modes that might come in future single-phase PV systems. In order to map future challenges, the relevant synchronization and control strategies are discussed. Some faulty modes are studied experimentally...... and provided at the end of this paper. It is concluded that there are extensive control possibilities in single-phase PV systems under grid faults. The Second Order General Integral based PLL technique might be the most promising candidate for future single-phase PV systems because of its fast adaptive...

Determining Maximum Photovoltaic Penetration in a Distribution Grid considering Grid Operation Limits

DEFF Research Database (Denmark)

Kordheili, Reza Ahmadi; Bak-Jensen, Birgitte; Pillai, Jayakrishnan Radhakrishna

2014-01-01

High penetration of photovoltaic panels in distribution grid can bring the grid to its operation limits. The main focus of the paper is to determine maximum photovoltaic penetration level in the grid. Three main criteria were investigated for determining maximum penetration level of PV panels...... for this grid: even distribution of PV panels, aggregation of panels at the beginning of each feeder, and aggregation of panels at the end of each feeder. Load modeling is done using Velander formula. Since PV generation is highest in the summer due to irradiation, a summer day was chosen to determine maximum......; maximum voltage deviation of customers, cables current limits, and transformer nominal value. Voltage deviation of different buses was investigated for different penetration levels. The proposed model was simulated on a Danish distribution grid. Three different PV location scenarios were investigated...

Data Compression of Hydrocarbon Reservoir Simulation Grids

KAUST Repository

Chavez, Gustavo Ivan

2015-05-28

A dense volumetric grid coming from an oil/gas reservoir simulation output is translated into a compact representation that supports desired features such as interactive visualization, geometric continuity, color mapping and quad representation. A set of four control curves per layer results from processing the grid data, and a complete set of these 3-dimensional surfaces represents the complete volume data and can map reservoir properties of interest to analysts. The processing results yield a representation of reservoir simulation results which has reduced data storage requirements and permits quick performance interaction between reservoir analysts and the simulation data. The degree of reservoir grid compression can be selected according to the quality required, by adjusting for different thresholds, such as approximation error and level of detail. The processions results are of potential benefit in applications such as interactive rendering, data compression, and in-situ visualization of large-scale oil/gas reservoir simulations.

Study of the integration of distributed generation systems in the grid: application in micro-grids

International Nuclear Information System (INIS)

Gaztanaga Arantzamendi, H.

2006-12-01

The present PhD deals with an original micro-grid concept and its application as a Renewable Energy Source's (RES) grid integration scheme. This micro-grid is composed of RES generators as well as support systems that incorporate additional functionalities in order to improve RES integration into the grid. According to this concept, two practical micro-grid applications have been studied in detail: a residential micro-grid and a wind farm supported by DFACTS systems (STATCOM and DVR). In both applications, the control structures which are implemented at different levels and applied to the different micro-grid elements have been developed, analyzed by means of off-line simulations and finally validated in real-time conditions with physical reduced-scale prototypes. (author)

Electric arc discharge damage to ion thruster grids

Science.gov (United States)

Beebe, D. D.; Nakanishi, S.; Finke, R. C.

1974-01-01

Arcs representative of those occurring between the grids of a mercury ion thruster were simulated. Parameters affecting an arc and the resulting damage were studied. The parameters investigated were arc energy, arc duration, and grid geometry. Arc attenuation techniques were also investigated. Potentially serious damage occurred at all energy levels representative of actual thruster operating conditions. Of the grids tested, the lowest open-area configuration sustained the least damage for given conditions. At a fixed energy level a long duration discharge caused greater damage than a short discharge. Attenuation of arc current using various impedances proved to be effective in reducing arc damage. Faults were also deliberately caused using chips of sputtered materials formed during the operation of an actual thruster. These faults were cleared with no serious grid damage resulting using the principles and methods developed in this study.

Coverage Metrics for Model Checking

Science.gov (United States)

Penix, John; Visser, Willem; Norvig, Peter (Technical Monitor)

2001-01-01

When using model checking to verify programs in practice, it is not usually possible to achieve complete coverage of the system. In this position paper we describe ongoing research within the Automated Software Engineering group at NASA Ames on the use of test coverage metrics to measure partial coverage and provide heuristic guidance for program model checking. We are specifically interested in applying and developing coverage metrics for concurrent programs that might be used to support certification of next generation avionics software.

FermiGrid-experience and future plans

International Nuclear Information System (INIS)

Chadwick, K; Berman, E; Canal, P; Hesselroth, T; Garzoglio, G; Levshina, T; Sergeev, V; Sfiligoi, I; Sharma, N; Timm, S; Yocum, D R

2008-01-01

Fermilab supports a scientific program that includes experiments and scientists located across the globe. In order to better serve this community, Fermilab has placed its production computer resources in a Campus Grid infrastructure called 'FermiGrid'. The FermiGrid infrastructure allows the large experiments at Fermilab to have priority access to their own resources, enables sharing of these resources in an opportunistic fashion, and movement of work (jobs, data) between the Campus Grid and National Grids such as Open Science Grid (OSG) and the Worldwide LHC Computing Grid Collaboration (WLCG). FermiGrid resources support multiple Virtual Organizations (VOs), including VOs from the OSG, EGEE, and the WLCG. Fermilab also makes leading contributions to the Open Science Grid in the areas of accounting, batch computing, grid security, job management, resource selection, site infrastructure, storage management, and VO services. Through the FermiGrid interfaces, authenticated and authorized VOs and individuals may access our core grid services, the 10,000+ Fermilab resident CPUs, near-petabyte (including CMS) online disk pools and the multi-petabyte Fermilab Mass Storage System. These core grid services include a site wide Globus gatekeeper, VO management services for several VOs, Fermilab site authorization services, grid user mapping services, as well as job accounting and monitoring, resource selection and data movement services. Access to these services is via standard and well-supported grid interfaces. We will report on the user experience of using the FermiGrid campus infrastructure interfaced to a national cyberinfrastructure - the successes and the problems

Dosimetric characteristics with spatial fractionation using electron grid therapy.

Science.gov (United States)

Meigooni, A S; Parker, S A; Zheng, J; Kalbaugh, K J; Regine, W F; Mohiuddin, M

2002-01-01

Recently, promising clinical results have been shown in the delivery of palliative treatments using megavoltage photon grid therapy. However, the use of megavoltage photon grid therapy is limited in the treatment of bulky superficial lesions where critical radiosensitive anatomical structures are present beyond tumor volumes. As a result, spatially fractionated electron grid therapy was investigated in this project. Dose distributions of 1.4-cm-thick cerrobend grid blocks were experimentally determined for electron beams ranging from 6 to 20 MeV. These blocks were designed and fabricated at out institution to fit into a 20 x 20-cm(2) electron cone of a commercially available linear accelerator. Beam profiles and percentage depth dose (PDD) curves were measured in Solid Water phantom material using radiographic film, LiF TLD, and ionometric techniques. Open-field PDD curves were compared with those of single holes grid with diameters of 1.5, 2.0, 2.5, 3.0, and 3.5 cm to find the optimum diameter. A 2.5-cm hole diameter was found to be the optimal size for all electron energies between 6 and 20 MeV. The results indicate peak-to-valley ratios decrease with depth and the largest ratio is found at Dmax. Also, the TLD measurements show that the dose under the blocked regions of the grid ranged from 9.7% to 39% of the dose beneath the grid holes, depending on the measurement location and beam energy.

Strategic Energy Management (SEM) in a micro grid with modern grid interactive electric vehicle

International Nuclear Information System (INIS)

Panwar, Lokesh Kumar; Reddy, K. Srikanth; Kumar, Rajesh; Panigrahi, B.K.; Vyas, Shashank

2015-01-01

Highlights: • System: Modelling of energy and storage systems for micro grid. • Target: Co-ordination of unitized regenerative fuel cell (URFC) and electric vehicle (EV). • Energy management strategies: Only URFC, URFC–EV charging, URFC-V2G with enabled. • Multi-objective approach: loss, cost minimization, maximization of stored energy. • Proposed Solution: Intelligent co-ordination of URFC and EV with V2G with most effective strategy. - Abstract: In this paper, strategic energy management in a micro grid is proposed incorporating two types of storage elements viz. unitised regenerative fuel cell (URFC) and electric vehicle (EV). Rather than a simple approach of optimizing micro grid operation to minimize line loss in the micro grid, this paper deals with multi objective optimization to minimize line loss, operational cost and maximize the value of stored energy of URFC and EV simultaneously. Apart from URFC, two operation strategies are proposed for EV enabling V2G operation to reduce overall system cost of operation. To address the complexity, non-linearity and multi dimensionality of the objective function, particle swarm optimization-a heuristic approach based solution methodology along with forward and back sweep algorithm based load flow solution technique is developed. Combined with particle swarm optimization (PSO), forward and backward sweep algorithm resolves the complexity and multi dimensionality of the load flow analysis and optimizes the operational cost of micro grid. The simulation results are presented and discussed which are promising with regard to reduction in line loss as well as cost of operation. Scheduling strategy of the micro grid with both URFC and EV enabling V2G operation presents a promising approach to minimize line loss and cost of operation.

Aspects of coverage in medical DNA sequencing

Directory of Open Access Journals (Sweden)

Wilson Richard K

2008-05-01

Full Text Available Abstract Background DNA sequencing is now emerging as an important component in biomedical studies of diseases like cancer. Short-read, highly parallel sequencing instruments are expected to be used heavily for such projects, but many design specifications have yet to be conclusively established. Perhaps the most fundamental of these is the redundancy required to detect sequence variations, which bears directly upon genomic coverage and the consequent resolving power for discerning somatic mutations. Results We address the medical sequencing coverage problem via an extension of the standard mathematical theory of haploid coverage. The expected diploid multi-fold coverage, as well as its generalization for aneuploidy are derived and these expressions can be readily evaluated for any project. The resulting theory is used as a scaling law to calibrate performance to that of standard BAC sequencing at 8× to 10× redundancy, i.e. for expected coverages that exceed 99% of the unique sequence. A differential strategy is formalized for tumor/normal studies wherein tumor samples are sequenced more deeply than normal ones. In particular, both tumor alleles should be detected at least twice, while both normal alleles are detected at least once. Our theory predicts these requirements can be met for tumor and normal redundancies of approximately 26× and 21×, respectively. We explain why these values do not differ by a factor of 2, as might intuitively be expected. Future technology developments should prompt even deeper sequencing of tumors, but the 21× value for normal samples is essentially a constant. Conclusion Given the assumptions of standard coverage theory, our model gives pragmatic estimates for required redundancy. The differential strategy should be an efficient means of identifying potential somatic mutations for further study.

Security Challenges in Smart-Grid Metering and Control Systems

Directory of Open Access Journals (Sweden)

Xinxin Fan

2013-07-01

Full Text Available The smart grid is a next-generation power system that is increasingly attracting the attention of government, industry, and academia. It is an upgraded electricity network that depends on two-way digital communications between supplier and consumer that in turn give support to intelligent metering and monitoring systems. Considering that energy utilities play an increasingly important role in our daily life, smart-grid technology introduces new security challenges that must be addressed. Deploying a smart grid without adequate security might result in serious consequences such as grid instability, utility fraud, and loss of user information and energy-consumption data. Due to the heterogeneous communication architecture of smart grids, it is quite a challenge to design sophisticated and robust security mechanisms that can be easily deployed to protect communications among different layers of the smart grid-infrastructure. In this article, we focus on the communication-security aspect of a smart-grid metering and control system from the perspective of cryptographic techniques, and we discuss different mechanisms to enhance cybersecurity of the emerging smart grid. We aim to provide a comprehensive vulnerability analysis as well as novel insights on the cybersecurity of a smart grid.

Numerical analysis of the spacer grids' compression strength

International Nuclear Information System (INIS)

Schettino, C.F.M.; Gouvea, J.P.; Medeiros, N.

2013-01-01

Among the components of the fuel assembly, the spacer grids play an important structural role during the energy generation process, mainly for their requirement to have enough structural strength to withstand lateral impact loads, due to fuel assembly shipping/handling and due to forces outcome from postulated accidents (earthquake and LOCA). This requirement ensures a proper geometry for cooling and for guide thimble straightness in the fuel assembly. In this way, the understanding of the macroscopic mechanical behavior of this component becomes essential even to any subsequent geometrical modifications to optimize the flue assemblies' structural behavior. In the present work, three-dimensional finite element models destined to provide consistent predictions of 16X16-type spacer grids lateral strength were proposed. Firstly, buckling tests based on results available in the literature were performed to establish a methodology for spacer grid finite element-based modeling. The, by considering a spacer grid interesting geometry and some possible variations associated to its fabrication, tolerance, the proposed numerical models were submitted to compression conditions to calculate the buckling force. Also, these models were validated for comparison with experimental buckling load results. Comparison of buckling predictions combined to observations of actual and simulated deformed spacer grids geometries permitted to verify the consistency and applicability of the proposed models. Thus, these numerical results show a good agreement between the and the experimental results. (author)

Study of Control Grid Thermionic Cathode RF Gun

CERN Document Server

Xiao, Jin; Ming, Li; Xinfan, Yang; Xumin, Shen; Yanan, Chen; Zhou, Xu

2004-01-01

In this paper, the beam loading effect of RF Gun was analyzed. To minimize the energy spread, the grid control RF Gun was introduced. The result shows that the grid congrol RF Gun can increase electron beam within 1% energy spread.

Adult vaccination coverage levels among users of complementary/alternative medicine - results from the 2002 National Health Interview Survey (NHIS).

Science.gov (United States)

Stokley, Shannon; Cullen, Karen A; Kennedy, Allison; Bardenheier, Barbara H

2008-02-22

While many Complementary/Alternative Medicine (CAM) practitioners do not object to immunization, some discourage or even actively oppose vaccination among their patients. However, previous studies in this area have focused on childhood immunizations, and it is unknown whether and to what extent CAM practitioners may influence the vaccination behavior of their adult patients. The purpose of this study was to describe vaccination coverage levels of adults aged > or = 18 years according to their CAM use status and determine if there is an association between CAM use and adult vaccination coverage. Data from the 2002 National Health Interview Survey, limited to 30,617 adults that provided at least one valid answer to the CAM supplement, were analyzed. Receipt of influenza vaccine during the past 12 months, pneumococcal vaccine (ever), and > or = 1 dose of hepatitis B vaccine was self-reported. Coverage levels for each vaccine by CAM use status were determined for adults who were considered high priority for vaccination because of the presence of a high risk condition and for non-priority adults. Multivariable analyses were conducted to evaluate the association between CAM users and vaccination status, adjusting for demographic and healthcare utilization characteristics. Overall, 36% were recent CAM users. Among priority adults, adjusted vaccination coverage levels were significantly different between recent and non-CAM users for influenza (44% vs 38%; p-value < 0.001) and pneumococcal (40% vs 33%; p-value < 0.001) vaccines but were not significantly different for hepatitis B (60% vs 56%; p-value = 0.36). Among non-priority adults, recent CAM users had significantly higher unadjusted and adjusted vaccination coverage levels compared to non-CAM users for all three vaccines (p-values < 0.001). Vaccination coverage levels among recent CAM users were found to be higher than non-CAM users. Because CAM use has been increasing over time in the U.S., it is important to continue

Mini-grid Policy Tool-kit. Policy and business frameworks for successful mini-grid roll-outs

International Nuclear Information System (INIS)

Franz, Michael; Hayek, Niklas; Peterschmidt, Nico; Rohrer, Michael; Kondev, Bozhil; Adib, Rana; Cader, Catherina; Carter, Andrew; George, Peter; Gichungi, Henry; Hankins, Mark; Kappiah, Mahama; Mangwengwende, Simbarashe E.

2014-01-01

The Mini-grid Policy Tool-kit is for policy makers to navigate the mini-grid policy design process. It contains information on mini-grid operator models, the economics of mini-grids, and necessary policy and regulation that must be considered for successful implementation. The publication specifically focuses on Africa. Progress on extending the electricity grid in many countries has remained slow because of high costs of gird-extension and limited utility/state budgets for electrification. Mini-grids provide an affordable and cost-effective option to extend needed electricity services. Putting in place the right policy for min-grid deployment requires considerable effort but can yield significant improvement in electricity access rates as examples from Kenya, Senegal and Tanzania illustrate. The tool-kit is available in English, French and Portuguese

SAGE - MULTIDIMENSIONAL SELF-ADAPTIVE GRID CODE

Science.gov (United States)

Davies, C. B.

1994-01-01

SAGE, Self Adaptive Grid codE, is a flexible tool for adapting and restructuring both 2D and 3D grids. Solution-adaptive grid methods are useful tools for efficient and accurate flow predictions. In supersonic and hypersonic flows, strong gradient regions such as shocks, contact discontinuities, shear layers, etc., require careful distribution of grid points to minimize grid error and produce accurate flow-field predictions. SAGE helps the user obtain more accurate solutions by intelligently redistributing (i.e. adapting) the original grid points based on an initial or interim flow-field solution. The user then computes a new solution using the adapted grid as input to the flow solver. The adaptive-grid methodology poses the problem in an algebraic, unidirectional manner for multi-dimensional adaptations. The procedure is analogous to applying tension and torsion spring forces proportional to the local flow gradient at every grid point and finding the equilibrium position of the resulting system of grid points. The multi-dimensional problem of grid adaption is split into a series of one-dimensional problems along the computational coordinate lines. The reduced one dimensional problem then requires a tridiagonal solver to find the location of grid points along a coordinate line. Multi-directional adaption is achieved by the sequential application of the method in each coordinate direction. The tension forces direct the redistribution of points to the strong gradient region. To maintain smoothness and a measure of orthogonality of grid lines, torsional forces are introduced that relate information between the family of lines adjacent to one another. The smoothness and orthogonality constraints are direction-dependent, since they relate only the coordinate lines that are being adapted to the neighboring lines that have already been adapted. Therefore the solutions are non-unique and depend on the order and direction of adaption. Non-uniqueness of the adapted grid is

Smart grid communication-enabled intelligence for the electric power grid

CERN Document Server

Bush, Stephen F

2014-01-01

This book bridges the divide between the fields of power systems engineering and computer communication through the new field of power system information theory. Written by an expert with vast experience in the field, this book explores the smart grid from generation to consumption, both as it is planned today and how it will evolve tomorrow. The book focuses upon what differentiates the smart grid from the ""traditional"" power grid as it has been known for the last century. Furthermore, the author provides the reader with a fundamental understanding of both power systems and communication ne

Challenges facing production grids

Energy Technology Data Exchange (ETDEWEB)

Pordes, Ruth; /Fermilab

2007-06-01

Today's global communities of users expect quality of service from distributed Grid systems equivalent to that their local data centers. This must be coupled to ubiquitous access to the ensemble of processing and storage resources across multiple Grid infrastructures. We are still facing significant challenges in meeting these expectations, especially in the underlying security, a sustainable and successful economic model, and smoothing the boundaries between administrative and technical domains. Using the Open Science Grid as an example, I examine the status and challenges of Grids operating in production today.

Online grid impedance estimation for single-phase grid-connected systems using PQ variations

DEFF Research Database (Denmark)

Ciobotaru, Mihai; Teodorescu, Remus; Rodriguez, Pedro

2007-01-01

algorithms are used in order to estimate the value of the grid impedance. The online grid impedance estimation method can be used for compliance with the anti-islanding standard requirements (IEEE1574, IEEE929 and VDE0126) and for adaptive control of the grid-connected converters. The proposed method...

An Evaluation of Information Consistency in Grid Information Systems

CERN Document Server

Field, Laurence

2017-01-01

A Grid information system resolves queries that may need to consider all information sources (Grid services), which are widely distributed geographically, in order to enable efficient Grid functions that may utilise multiple cooperating services. Fundamentally this can be achieved by either moving the query to the data (query shipping) or moving the data to the query (data shipping). Existing Grid information system implementations have adopted one of the two approaches. This paper explores the two approaches in further detail by evaluating them to the best possible extent with respect to Grid information system benchmarking metrics. A Grid information system that follows the data shipping approach based on the replication of information that aims to improve the currency for highly-mutable information is presented. An implementation of this, based on an Enterprise Messaging System, is evaluated using the benchmarking method and the consequence of the results for the design of Grid information systems is discu...

Energy-efficient area coverage for intruder detection in sensor networks

CERN Document Server

He, Shibo; Li, Junkun

2014-01-01

This Springer Brief presents recent research results on area coverage for intruder detection from an energy-efficient perspective. These results cover a variety of topics, including environmental surveillance and security monitoring. The authors also provide the background and range of applications for area coverage and elaborate on system models such as the formal definition of area coverage and sensing models. Several chapters focus on energy-efficient intruder detection and intruder trapping under the well-known binary sensing model, along with intruder trapping under the probabilistic sens

Efficient Pseudorecursive Evaluation Schemes for Non-adaptive Sparse Grids

KAUST Repository

Buse, Gerrit

2014-01-01

In this work we propose novel algorithms for storing and evaluating sparse grid functions, operating on regular (not spatially adaptive), yet potentially dimensionally adaptive grid types. Besides regular sparse grids our approach includes truncated grids, both with and without boundary grid points. Similar to the implicit data structures proposed in Feuersänger (Dünngitterverfahren für hochdimensionale elliptische partielle Differntialgleichungen. Diploma Thesis, Institut für Numerische Simulation, Universität Bonn, 2005) and Murarasu et al. (Proceedings of the 16th ACM Symposium on Principles and Practice of Parallel Programming. Cambridge University Press, New York, 2011, pp. 25–34) we also define a bijective mapping from the multi-dimensional space of grid points to a contiguous index, such that the grid data can be stored in a simple array without overhead. Our approach is especially well-suited to exploit all levels of current commodity hardware, including cache-levels and vector extensions. Furthermore, this kind of data structure is extremely attractive for today’s real-time applications, as it gives direct access to the hierarchical structure of the grids, while outperforming other common sparse grid structures (hash maps, etc.) which do not match with modern compute platforms that well. For dimensionality d ≤ 10 we achieve good speedups on a 12 core Intel Westmere-EP NUMA platform compared to the results presented in Murarasu et al. (Proceedings of the International Conference on Computational Science—ICCS 2012. Procedia Computer Science, 2012). As we show, this also holds for the results obtained on Nvidia Fermi GPUs, for which we observe speedups over our own CPU implementation of up to 4.5 when dealing with moderate dimensionality. In high-dimensional settings, in the order of tens to hundreds of dimensions, our sparse grid evaluation kernels on the CPU outperform any other known implementation.

Measuring coverage in MNCH: a validation study linking population survey derived coverage to maternal, newborn, and child health care records in rural China.

Directory of Open Access Journals (Sweden)

Li Liu

Full Text Available Accurate data on coverage of key maternal, newborn, and child health (MNCH interventions are crucial for monitoring progress toward the Millennium Development Goals 4 and 5. Coverage estimates are primarily obtained from routine population surveys through self-reporting, the validity of which is not well understood. We aimed to examine the validity of the coverage of selected MNCH interventions in Gongcheng County, China.We conducted a validation study by comparing women's self-reported coverage of MNCH interventions relating to antenatal and postnatal care, mode of delivery, and child vaccinations in a community survey with their paper- and electronic-based health care records, treating the health care records as the reference standard. Of 936 women recruited, 914 (97.6% completed the survey. Results show that self-reported coverage of these interventions had moderate to high sensitivity (0.57 [95% confidence interval (CI: 0.50-0.63] to 0.99 [95% CI: 0.98-1.00] and low to high specificity (0 to 0.83 [95% CI: 0.80-0.86]. Despite varying overall validity, with the area under the receiver operating characteristic curve (AUC ranging between 0.49 [95% CI: 0.39-0.57] and 0.90 [95% CI: 0.88-0.92], bias in the coverage estimates at the population level was small to moderate, with the test to actual positive (TAP ratio ranging between 0.8 and 1.5 for 24 of the 28 indicators examined. Our ability to accurately estimate validity was affected by several caveats associated with the reference standard. Caution should be exercised when generalizing the results to other settings.The overall validity of self-reported coverage was moderate across selected MNCH indicators. However, at the population level, self-reported coverage appears to have small to moderate degree of bias. Accuracy of the coverage was particularly high for indicators with high recorded coverage or low recorded coverage but high specificity. The study provides insights into the accuracy of

The Benefits of Grid Networks

Science.gov (United States)

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.

On Connected Target k-Coverage in Heterogeneous Wireless Sensor Networks.

Science.gov (United States)

Yu, Jiguo; Chen, Ying; Ma, Liran; Huang, Baogui; Cheng, Xiuzhen

2016-01-15

Coverage and connectivity are two important performance evaluation indices for wireless sensor networks (WSNs). In this paper, we focus on the connected target k-coverage (CTC k) problem in heterogeneous wireless sensor networks (HWSNs). A centralized connected target k-coverage algorithm (CCTC k) and a distributed connected target k-coverage algorithm (DCTC k) are proposed so as to generate connected cover sets for energy-efficient connectivity and coverage maintenance. To be specific, our proposed algorithms aim at achieving minimum connected target k-coverage, where each target in the monitored region is covered by at least k active sensor nodes. In addition, these two algorithms strive to minimize the total number of active sensor nodes and guarantee that each sensor node is connected to a sink, such that the sensed data can be forwarded to the sink. Our theoretical analysis and simulation results show that our proposed algorithms outperform a state-of-art connected k-coverage protocol for HWSNs.

Power grids

International Nuclear Information System (INIS)

Viterbo, J.

2012-01-01

The implementation of renewable energies represents new challenges for electrical systems. The objective: making power grids smarter so they can handle intermittent production. The advent of smart grids will allow flexible operations like distributing energy in a multidirectional manner instead of just one way and it will make electrical systems capable of integrating actions by different users, consumers and producers in order to maintain efficient, sustainable, economical and secure power supplies. Practically speaking, they associate sensors, instrumentation and controls with information processing and communication systems in order to create massively automated networks. Smart grids require huge investments: for example more than 7 billion dollars have been invested in China and in the Usa in 2010 and France is ranked 9. worldwide with 265 million dollars invested. It is expected that smart grids will promote the development of new business models and a change in the value chain for energy. Decentralized production combined with the probable introduction of more or less flexible rates for sales or purchases and of new supplier-customer relationships will open the way to the creation of new businesses. (A.C.)

Improving nuclear generating station response for electrical grid islanding

International Nuclear Information System (INIS)

Chou, Q.B.; Kundur, P.; Acchione, P.N.; Lautsch, B.

1989-01-01

This paper describes problems associated with the performance characteristics of nuclear generating stations which do not have their overall plant control design functions co-ordinated with the other grid controls. The paper presents some design changes to typical nuclear plant controls which result in a significant improvement in both the performance of the grid island and the chances of the nuclear units staying on-line following the disturbance. This paper focuses on four areas of the overall unit controls and turbine governor controls which could be modified to better co-ordinate the control functions of the nuclear units with the electrical grid. Some simulation results are presented to show the performance of a typical electrical grid island containing a nuclear unit with and without the changes

Recent trends in grid computing

International Nuclear Information System (INIS)

Miura, Kenichi

2004-01-01

Grid computing is a technology which allows uniform and transparent access to geographically dispersed computational resources, such as computers, databases, experimental and observational equipment etc. via high-speed, high-bandwidth networking. The commonly used analogy is that of electrical power grid, whereby the household electricity is made available from outlets on the wall, and little thought need to be given to where the electricity is generated and how it is transmitted. The usage of grid also includes distributed parallel computing, high through-put computing, data intensive computing (data grid) and collaborative computing. This paper reviews the historical background, software structure, current status and on-going grid projects, including applications of grid technology to nuclear fusion research. (author)

GRID and FMPhI-UNIBA

International Nuclear Information System (INIS)

Babik, M.; Daranyi, T.; Fekete, V.; Stavina, P.; Zagiba, M.; Zenis, T.

2008-01-01

The word GRID has several meanings, so it is not an abbreviation. All of them have in common description of GRID as a form of hardware and software and software solution for distributive computing. Additionally, word GRID is also used for distributive computing of many computers and not one super computer with several processors. It, of course, does not mean that such a supercomputer cannot be a part of the GRID. Typical task for GRID is computer programs execution and to data storage. (Authors)

Flicker Mitigation of Grid Connected Wind Turbines Using STATCOM

DEFF Research Database (Denmark)

Sun, Tao; Chen, Zhe; Blaabjerg, Frede

2004-01-01

to the point of common coupling (PCC) to relieve the flicker produced by grid connected wind turbines and the corresponding control scheme is described in detail. Simulation results show that STATCOM is an effective measure to mitigate the flicker level during continuous operation of grid connected wind......Grid connected wind turbines may produce flicker during continuous operation. In this paper flicker emission of grid connected wind turbines with doubly fed induction generators is investigated during continuous operation. A STATCOM using PWM voltage source converter (VSC) is connected in shunt...

Calibrated, Enhanced-Resolution Brightness Temperature Earth System Data Record: A New Era for Gridded Passive Microwave Data

Science.gov (United States)

Hardman, M.; Brodzik, M. J.; Long, D. G.

2017-12-01

Since 1978, the satellite passive microwave data record has been a mainstay of remote sensing of the cryosphere, providing twice-daily, near-global spatial coverage for monitoring changes in hydrologic and cryospheric parameters that include precipitation, soil moisture, surface water, vegetation, snow water equivalent, sea ice concentration and sea ice motion. Up until recently, the available global gridded passive microwave data sets have not been produced consistently. Various projections (equal-area, polar stereographic), a number of different gridding techniques were used, along with various temporal sampling as well as a mix of Level 2 source data versions. In addition, not all data from all sensors have been processed completely and they have not been processed in any one consistent way. Furthermore, the original gridding techniques were relatively primitive and were produced on 25 km grids using the original EASE-Grid definition that is not easily accommodated in modern software packages. As part of NASA MEaSUREs, we have re-processed all data from SMMR, all SSM/I-SSMIS and AMSR-E instruments, using the most mature Level 2 data. The Calibrated, Enhanced-Resolution Brightness Temperature (CETB) Earth System Data Record (ESDR) gridded data are now available from the NSIDC DAAC. The data are distributed as netCDF files that comply with CF-1.6 and ACDD-1.3 conventions. The data have been produced on EASE 2.0 projections at smoothed, 25 kilometer resolution and spatially-enhanced resolutions, up to 3.125 km depending on channel frequency, using the radiometer version of the Scatterometer Image Reconstruction (rSIR) method. We expect this newly produced data set to enable scientists to better analyze trends in coastal regions, marginal ice zones and in mountainous terrain that were not possible with the previous gridded passive microwave data. The use of the EASE-Grid 2.0 definition and netCDF-CF formatting allows users to extract compliant geotiff images and

Identification of grid model parameters using synchrophasor measurements

Energy Technology Data Exchange (ETDEWEB)

Boicea, Valentin; Albu, Mihaela [Politehnica University of Bucharest (Romania)

2012-07-01

Presently a critical element of the energy networks is represented by the active distribution grids, where generation intermittency and controllable loads contribute to a stochastic varability of the quantities characterizing the grid operation. The capability of controlling the electrical energy transfer is also limited by the incomplete knowledge of the detailed electrical model of each of the grid components. Asset management in distribution grids has to consider dynamic loads, while high loading of network sections might already have degraded some of the assets. Moreover, in case of functional microgrids, all elements need to be modelled accurately and an appropriate measurement layer enabling online control needs to be deployed. In this paper a method for online identification of the actual parameter values in grid electrical models is proposed. Laboratory results validating the proposed method are presented. (orig.)

Multi-Grid Lanczos

Science.gov (United States)

Clark, M. A.; Jung, Chulwoo; Lehner, Christoph

2018-03-01

We present a Lanczos algorithm utilizing multiple grids that reduces the memory requirements both on disk and in working memory by one order of magnitude for RBC/UKQCD's 48I and 64I ensembles at the physical pion mass. The precision of the resulting eigenvectors is on par with exact deflation.

Pressure Drop of Chamfer on Spacer Grid Strap

Energy Technology Data Exchange (ETDEWEB)

Kim, Euijae; Kim, Kanghoon; Kim, Kyounghong; Nahm, Keeyil [KEPCO Nuclear Fuel Co., Daejeon (Korea, Republic of)

2014-05-15

A swirl flow and cross flow are generated by the spacer grid with mixing vane that enhances the thermal performance and critical heat flux (CHF). The additional pressure drop makes it difficult to meet acceptance criteria for overall pressure drop in fuel assembly depending upon the pump capacity. The chamfer on the end of spacer grid strap is one solution to reduce additional pressure drop without any adverse effect on flow fields. In this research, the pressure drop tests for spacer grid with and without chamfer were carried out at the hydraulic test facility. The result can be applied to develop high performance nuclear fuel assemblies for Pressurized Water Reactor (PWR) plants. The pressure drop tests for 5x5 spacer grid with and without chamfer as well as 6x6 spacer grid with and without chamfer were carried out at the INFINIT test facility. The Reynolds number ranged about from 16000 to 75000. The sweep-up and sweep-down test showed that the direction of sweep did not affect the pressure drop. The chamfer on spacer grid strap reduced the pressure drop due to the decreased in ratio of inlet area to outlet area. The pressure loss coefficient for spacer grid with chamfer was by up to 13.8 % lower than that for spacer grid without chamfer. Hence, the chamfer on spacer grid strap was one of effective ways to reduce the pressure drop.

5 CFR 890.1106 - Coverage.

Science.gov (United States)

2010-01-01

... family member is an individual whose relationship to the enrollee meets the requirements of 5 U.S.C. 8901... EMPLOYEES HEALTH BENEFITS PROGRAM Temporary Continuation of Coverage § 890.1106 Coverage. (a) Type of enrollment. An individual who enrolls under this subpart may elect coverage for self alone or self and family...

Sparse grid techniques for particle-in-cell schemes

Science.gov (United States)

Ricketson, L. F.; Cerfon, A. J.

2017-02-01

We propose the use of sparse grids to accelerate particle-in-cell (PIC) schemes. By using the so-called ‘combination technique’ from the sparse grids literature, we are able to dramatically increase the size of the spatial cells in multi-dimensional PIC schemes while paying only a slight penalty in grid-based error. The resulting increase in cell size allows us to reduce the statistical noise in the simulation without increasing total particle number. We present initial proof-of-principle results from test cases in two and three dimensions that demonstrate the new scheme’s efficiency, both in terms of computation time and memory usage.

Critical Infrastructure Protection: EMP Impacts on the U.S. Electric Grid

Science.gov (United States)

Boston, Edwin J., Jr.

The purpose of this research is to identify the United States electric grid infrastructure systems vulnerabilities to electromagnetic pulse attacks and the cyber-based impacts of those vulnerabilities to the electric grid. Additionally, the research identifies multiple defensive strategies designed to harden the electric grid against electromagnetic pulse attack that include prevention, mitigation and recovery postures. Research results confirm the importance of the electric grid to the United States critical infrastructures system and that an electromagnetic pulse attack against the electric grid could result in electric grid degradation, critical infrastructure(s) damage and the potential for societal collapse. The conclusions of this research indicate that while an electromagnetic pulse attack against the United States electric grid could have catastrophic impacts on American society, there are currently many defensive strategies under consideration designed to prevent, mitigate and or recover from an electromagnetic pulse attack. However, additional research is essential to further identify future target hardening opportunities, efficient implementation strategies and funding resources.

Control and Optimization Methods for Electric Smart Grids

CERN Document Server

Ilić, Marija

2012-01-01

Control and Optimization Methods for Electric Smart Grids brings together leading experts in power, control and communication systems,and consolidates some of the most promising recent research in smart grid modeling,control and optimization in hopes of laying the foundation for future advances in this critical field of study. The contents comprise eighteen essays addressing wide varieties of control-theoretic problems for tomorrow’s power grid. Topics covered include: Control architectures for power system networks with large-scale penetration of renewable energy and plug-in vehicles Optimal demand response New modeling methods for electricity markets Control strategies for data centers Cyber-security Wide-area monitoring and control using synchronized phasor measurements. The authors present theoretical results supported by illustrative examples and practical case studies, making the material comprehensible to a wide audience. The results reflect the exponential transformation that today’s grid is going...

Evaluation of Smart Grid Technologies Employed for System Reliability Improvement: Pacific Northwest Smart Grid Demonstration Experience

Energy Technology Data Exchange (ETDEWEB)

Agalgaonkar, Yashodhan P.; Hammerstrom, Donald J.

2017-06-01

The Pacific Northwest Smart Grid Demonstration (PNWSGD) was a smart grid technology performance evaluation project that included multiple U.S. states and cooperation from multiple electric utilities in the northwest region. One of the local objectives for the project was to achieve improved distribution system reliability. Toward this end, some PNWSGD utilities automated their distribution systems, including the application of fault detection, isolation, and restoration and advanced metering infrastructure. In light of this investment, a major challenge was to establish a correlation between implementation of these smart grid technologies and actual improvements of distribution system reliability. This paper proposes using Welch’s t-test to objectively determine and quantify whether distribution system reliability is improving over time. The proposed methodology is generic, and it can be implemented by any utility after calculation of the standard reliability indices. The effectiveness of the proposed hypothesis testing approach is demonstrated through comprehensive practical results. It is believed that wider adoption of the proposed approach can help utilities to evaluate a realistic long-term performance of smart grid technologies.

On transferring the grid technology to the biomedical community.

Science.gov (United States)

Mohammed, Yassene; Sax, Ulrich; Dickmann, Frank; Lippert, Joerg; Solodenko, Juri; von Voigt, Gabriele; Smith, Matthew; Rienhoff, Otto

2010-01-01

Natural scientists such as physicists pioneered the sharing of computing resources, which resulted in the Grid. The inter domain transfer process of this technology has been an intuitive process. Some difficulties facing the life science community can be understood using the Bozeman's "Effectiveness Model of Technology Transfer". Bozeman's and classical technology transfer approaches deal with technologies that have achieved certain stability. Grid and Cloud solutions are technologies that are still in flux. We illustrate how Grid computing creates new difficulties for the technology transfer process that are not considered in Bozeman's model. We show why the success of health Grids should be measured by the qualified scientific human capital and opportunities created, and not primarily by the market impact. With two examples we show how the Grid technology transfer theory corresponds to the reality. We conclude with recommendations that can help improve the adoption of Grid solutions into the biomedical community. These results give a more concise explanation of the difficulties most life science IT projects are facing in the late funding periods, and show some leveraging steps which can help to overcome the "vale of tears".

A Theorem on Grid Access Control

Institute of Scientific and Technical Information of China (English)

XU ZhiWei(徐志伟); BU GuanYing(卜冠英)

2003-01-01

The current grid security research is mainly focused on the authentication of grid systems. A problem to be solved by grid systems is to ensure consistent access control. This problem is complicated because the hosts in a grid computing environment usually span multiple autonomous administrative domains. This paper presents a grid access control model, based on asynchronous automata theory and the classic Bell-LaPadula model. This model is useful to formally study the confidentiality and integrity problems in a grid computing environment. A theorem is proved, which gives the necessary and sufficient conditions to a grid to maintain confidentiality.These conditions are the formalized descriptions of local (node) relations or relationship between grid subjects and node subjects.

Massachusetts health reform: employer coverage from employees' perspective.

Science.gov (United States)

Long, Sharon K; Stockley, Karen

2009-01-01

The national health reform debate continues to draw on Massachusetts' 2006 reform initiative, with a focus on sustaining employer-sponsored insurance. This study provides an update on employers' responses under health reform in fall 2008, using data from surveys of working-age adults. Results show that concerns about employers' dropping coverage or scaling back benefits under health reform have not been realized. Access to employer coverage has increased, as has the scope and quality of their coverage as assessed by workers. However, premiums and out-of-pocket costs have become more of an issue for employees in small firms.

Transmission grid security

CERN Document Server

Haarla, Liisa; Hirvonen, Ritva; Labeau, Pierre-Etienne

2011-01-01

In response to the growing importance of power system security and reliability, ""Transmission Grid Security"" proposes a systematic and probabilistic approach for transmission grid security analysis. The analysis presented uses probabilistic safety assessment (PSA) and takes into account the power system dynamics after severe faults. In the method shown in this book the power system states (stable, not stable, system breakdown, etc.) are connected with the substation reliability model. In this way it is possible to: estimate the system-wide consequences of grid faults; identify a chain of eve

A policy system for Grid Management and Monitoring

International Nuclear Information System (INIS)

Stagni, Federico; Santinelli, Roberto

2011-01-01

Organizations using a Grid computing model are faced with non-traditional administrative challenges: the heterogeneous nature of the underlying resources requires professionals acting as Grid Administrators. Members of a Virtual Organization (VO) can use a subset of available resources and services in the grid infrastructure and in an ideal world, the more resources are exploited the better. In the real world, the less faulty services, the better: experienced Grid administrators apply procedures for adding and removing services, based on their status, as it is reported by an ever-growing set of monitoring tools. When a procedure is agreed and well-exercised, a formal policy could be derived. For this reason, using the DIRAC framework in the LHCb collaboration, we developed a policy system that can enforce management and operational policies, in a VO-specific fashion. A single policy makes an assessment on the status of a subject, relative to one or more monitoring information. Subjects of the policies are monitored entities of an established Grid ontology. The status of a same entity is evaluated against a number of policies, whose results are then combined by a Policy Decision Point. Such results are enforced in a Policy Enforcing Point, which provides plug-ins for actions, like raising alarms, sending notifications, automatic addition and removal of services and resources from the Grid mask. Policy results are shown in the web portal, and site-specific views are provided also. This innovative system provides advantages in terms of procedures automation, information aggregation and problem solving.

A policy system for Grid Management and Monitoring

Science.gov (United States)

Stagni, Federico; Santinelli, Roberto; LHCb Collaboration

2011-12-01

Organizations using a Grid computing model are faced with non-traditional administrative challenges: the heterogeneous nature of the underlying resources requires professionals acting as Grid Administrators. Members of a Virtual Organization (VO) can use a subset of available resources and services in the grid infrastructure and in an ideal world, the more resoures are exploited the better. In the real world, the less faulty services, the better: experienced Grid administrators apply procedures for adding and removing services, based on their status, as it is reported by an ever-growing set of monitoring tools. When a procedure is agreed and well-exercised, a formal policy could be derived. For this reason, using the DIRAC framework in the LHCb collaboration, we developed a policy system that can enforce management and operational policies, in a VO-specific fashion. A single policy makes an assessment on the status of a subject, relative to one or more monitoring information. Subjects of the policies are monitored entities of an established Grid ontology. The status of a same entity is evaluated against a number of policies, whose results are then combined by a Policy Decision Point. Such results are enforced in a Policy Enforcing Point, which provides plug-ins for actions, like raising alarms, sending notifications, automatic addition and removal of services and resources from the Grid mask. Policy results are shown in the web portal, and site-specific views are provided also. This innovative system provides advantages in terms of procedures automation, information aggregation and problem solving.

29 CFR 801.3 - Coverage.

Science.gov (United States)

2010-07-01

... 29 Labor 3 2010-07-01 2010-07-01 false Coverage. 801.3 Section 801.3 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR OTHER LAWS APPLICATION OF THE EMPLOYEE POLYGRAPH PROTECTION ACT OF 1988 General § 801.3 Coverage. (a) The coverage of the Act extends to “any...

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

Energy Technology Data Exchange (ETDEWEB)

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.

PV-hybrid and mini-grid

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-07-01

photovoltaic - fuel cell - direct storage - power supply units; (11) Djungle power - A more remote AC bus; (12) Quality control tools applied to a PV micro-grid in Ecuador; (13) Integral Evaluation of energy supply systems at Mountain Refuges; (14) Hyress project: Study case of Tunisia. Installation, set-up and first results; (15) PV hybrid systems on Mountain Huts: The experience with the project CAI ENERGIA 2000; (16) Process management in zero-emission communities: Adaptation of consumption and production; (17) TRNSYS simulation of a system consisted of PV panels and H{sub 2} production and storage to feed a Remote Telecom Application (HildrosolarH2); (18) Photovoltaic forecasting: A state of the art; (19) PV*SOL 5.0 standalone - Simulation of a stand-alone AC system; (20) Effect of wind speed and solar irradiation on the optimization of a PV wind battery system to supply a Telecommunications station; (21) Polysun: PV, wind and power-heat cogeneration in one design tool; (22) Comparative study between distributed and centralised PV generation in Island power systems under variable weather conditions; (23) Development of a test facility for PV-wind hybrid energy systems; (24) Evaluation of a micro PV-wind hybrid system in Nordic climate conditions; (25) Prismes: The INES micro-grid platform; (26) Estimation of statistical electric energy demand profiles of non electrified regions in Northern Brazil.

Gridded National Inventory of U.S. Methane Emissions

Science.gov (United States)

Maasakkers, Joannes D.; Jacob, Daniel J.; Sulprizio, Melissa P.; Turner, Alexander J.; Weitz, Melissa; Wirth, Tom; Hight, Cate; DeFigueiredo, Mark; Desai, Mausami; Schmeltz, Rachel;

The more the merrier: grid based modelling of Kepler dwarfs with 5-dimensional stellar grids

Directory of Open Access Journals (Sweden)

Serenelli Aldo

2017-01-01

Full Text Available We present preliminary results of our grid based modelling (GBM of the dwarf/subgiant sample of stars observed with Kepler including global asteroseismic parameters. GBM analysis in this work is based on a large grid of stellar models that is characterized by five independent parameters: model mass and age, initial metallicity (Zini, initial helium (Yini, and mixing length parameter (αMLT. Using this grid relaxes assumptions used in all previous GBM work where the initial composition is determined by a single parameter and that αMLT is fixed to a solar-calibrated value. The new grid allows us to study, for example, the impact of different galactic chemical enrichment models on the determination of stellar parameters such as mass radius and age. Also, it allows to include new results from stellar atmosphere models on αMLT in the GBM analysis in a simple manner. Alternatively, it can be tested if global asteroseismology is a useful tool to constraint our ignorance on quantities such as Yini and αMLT. Initial findings show that mass determination is robust with respect to freedom in the latter quantities, with a 4.4% maximum deviation for extreme assumptions regarding prior information on Yini – Zini relations and aMLT. On the other hand, tests carried out so far seem to indicate that global seismology does not have much power to constrain Yini – Zni relations of αMLT values without resourcing to additional information.

Grid Integration of Wind Farms

Science.gov (United States)

Giæver Tande, John Olav

2003-07-01

This article gives an overview of grid integration of wind farms with respect to impact on voltage quality and power system stability. The recommended procedure for assessing the impact of wind turbines on voltage quality in distribution grids is presented. The procedure uses the power quality characteristic data of wind turbines to determine the impact on slow voltage variations, flicker, voltage dips and harmonics. The detailed assessment allows for substantially more wind power in distribution grids compared with previously used rule-of-thumb guidelines. Power system stability is a concern in conjunction with large wind farms or very weak grids. Assessment requires the use of power system simulation tools, and wind farm models for inclusion in such tools are presently being developed. A fixed-speed wind turbine model is described. The model may be considered a good starting point for development of more advanced models, hereunder the concept of variable-speed wind turbines with a doubly fed induction generator is briefly explained. The use of dynamic wind farm models as part of power system simulation tools allows for detailed studies and development of innovative grid integration techniques. It is demonstrated that the use of reactive compensation may relax the short-term voltage stability limit and allow integration of significantly more wind power, and that application of automatic generation control technology may be an efficient means to circumvent thermal transmission capacity constraints. The continuous development of analysis tools and technology for cost-effective and secure grid integration is an important aid to ensure the increasing use of wind energy. A key factor for success, however, is the communication of results and gained experience, and in this regard it is hoped that this article may contribute.

Prosumers and smart grid technologies in Denmark: developing user competences in smart grid households

DEFF Research Database (Denmark)

Hansen, Meiken; Hauge, Bettina

2017-01-01

This paper explores and describes resident’s experiences from a smart grid project that involved 20 households in a rural area in Denmark and ran from 2014 to 2015. The study is based on qualitative data from the participating households, collected 6, 12 and 18 months after the start...... of the intervention. Drawing on theories of social practice and the three intertwined elements of a practice: competences, images and materials, the paper contributes with an in-depth analysis of a complex intervention, focusing on how the participants changed energy practices as a result of the installed smart grid...

GrEMBOSS: EMBOSS over the EELA GRID

International Nuclear Information System (INIS)

Bonavides-Martinez, C.; Murrieta-Leon, E.; Verleyen, J.; Zayas-Lagunas, R.; Hernandez-Alvarez, A.; Rodriguez-Bahena, R.; Valverde, J. R.; Branger, P. A.; Sarachu, M.

2007-01-01

With the growth of genome databases and the implied complexity for processing such information within bioinformatics research, there is a need for computing power and massive storage facilities which can be provided by Grid infrastructures. EMBOSS is a free Open Source sequence analysis package specially developed for the needs of the bioinformatics and molecular biology user community. This work describes the deployment of EMBOSS over the EELA and EGEE Grids, both gLite middle ware-based infrastructures. This work is focused on rewriting the I/O EMBOSS libraries (AJAX) to use the GFAL from the LCG/EGEE middle ware. This library allows the use of files registered on the catalog service which are contained in the storage elements of a Grid. Submitting a job into a Grid is not an intuitive task. This work also describes an ad hoc mechanism to allow bioinformaticians to concentrate on the EMBOSS command, instead of acquiring advanced knowledge about Grid usage. The results obtained so far demonstrate the functionality of GrEMBOSS, and represent an efficient and viable alternative for gridifying other bioinformatics applications. (Author)

GrEMBOSS: EMBOSS over the EELA GRID

Energy Technology Data Exchange (ETDEWEB)

Bonavides-Martinez, C.; Murrieta-Leon, E.; Verleyen, J.; Zayas-Lagunas, R.; Hernandez-Alvarez, A.; Rodriguez-Bahena, R.; Valverde, J. R.; Branger, P. A.; Sarachu, M.

2007-07-01

With the growth of genome databases and the implied complexity for processing such information within bioinformatics research, there is a need for computing power and massive storage facilities which can be provided by Grid infrastructures. EMBOSS is a free Open Source sequence analysis package specially developed for the needs of the bioinformatics and molecular biology user community. This work describes the deployment of EMBOSS over the EELA and EGEE Grids, both gLite middle ware-based infrastructures. This work is focused on rewriting the I/O EMBOSS libraries (AJAX) to use the GFAL from the LCG/EGEE middle ware. This library allows the use of files registered on the catalog service which are contained in the storage elements of a Grid. Submitting a job into a Grid is not an intuitive task. This work also describes an ad hoc mechanism to allow bioinformaticians to concentrate on the EMBOSS command, instead of acquiring advanced knowledge about Grid usage. The results obtained so far demonstrate the functionality of GrEMBOSS, and represent an efficient and viable alternative for gridifying other bioinformatics applications. (Author)

Smarter energy from smart metering to the smart grid

CERN Document Server

Sun, Hongjian; Poor, H Vincent; Carpanini, Laurence; Fornié, Miguel Angel Sánchez

2016-01-01

This book presents cutting-edge perspectives and research results in smart energy spanning multiple disciplines across four main topics: smart metering, smart grid modeling, control and optimisation, and smart grid communications and networking.

Adaptive Micro-Grid Operation Based on IEC 61850

Directory of Open Access Journals (Sweden)

Wei Deng

2015-05-01

Full Text Available Automatically identifying the new equipment after its integration and adjusting operation strategy to realize “plug and play” functionality are becoming essential for micro-grid operations. In order to improve and perfect the micro-grid “plug and play” function with the increased amount of equipment with different information protocols and more diverse system applications, this paper presents a solution for adaptive micro-grid operation based on IEC 61850, and proposes the design and specific implementation methods of micro-grid “plug and play” function and system operation mode conversion in detail, by using the established IEC 61850 information model of a micro-grid. Actual operation tests based on the developed IED and micro-grid test platform are performed to verify the feasibility and validity of the proposed solution. The tests results show that the solution can automatically identify the IEC 61850 information model of equipment after its integration, intelligently adjust the operation strategies to adapt to new system states and achieves a reliable system operation mode conversion.

Coverage-based constraints for IMRT optimization

Science.gov (United States)

Mescher, H.; Ulrich, S.; Bangert, M.

2017-09-01

Radiation therapy treatment planning requires an incorporation of uncertainties in order to guarantee an adequate irradiation of the tumor volumes. In current clinical practice, uncertainties are accounted for implicitly with an expansion of the target volume according to generic margin recipes. Alternatively, it is possible to account for uncertainties by explicit minimization of objectives that describe worst-case treatment scenarios, the expectation value of the treatment or the coverage probability of the target volumes during treatment planning. In this note we show that approaches relying on objectives to induce a specific coverage of the clinical target volumes are inevitably sensitive to variation of the relative weighting of the objectives. To address this issue, we introduce coverage-based constraints for intensity-modulated radiation therapy (IMRT) treatment planning. Our implementation follows the concept of coverage-optimized planning that considers explicit error scenarios to calculate and optimize patient-specific probabilities q(\\hat{d}, \\hat{v}) of covering a specific target volume fraction \\hat{v} with a certain dose \\hat{d} . Using a constraint-based reformulation of coverage-based objectives we eliminate the trade-off between coverage and competing objectives during treatment planning. In-depth convergence tests including 324 treatment plan optimizations demonstrate the reliability of coverage-based constraints for varying levels of probability, dose and volume. General clinical applicability of coverage-based constraints is demonstrated for two cases. A sensitivity analysis regarding penalty variations within this planing study based on IMRT treatment planning using (1) coverage-based constraints, (2) coverage-based objectives, (3) probabilistic optimization, (4) robust optimization and (5) conventional margins illustrates the potential benefit of coverage-based constraints that do not require tedious adjustment of target volume objectives.

The eGo grid model: An open-source and open-data based synthetic medium-voltage grid model for distribution power supply systems

Science.gov (United States)

Amme, J.; Pleßmann, G.; Bühler, J.; Hülk, L.; Kötter, E.; Schwaegerl, P.

2018-02-01

The increasing integration of renewable energy into the electricity supply system creates new challenges for distribution grids. The planning and operation of distribution systems requires appropriate grid models that consider the heterogeneity of existing grids. In this paper, we describe a novel method to generate synthetic medium-voltage (MV) grids, which we applied in our DIstribution Network GeneratOr (DINGO). DINGO is open-source software and uses freely available data. Medium-voltage grid topologies are synthesized based on location and electricity demand in defined demand areas. For this purpose, we use GIS data containing demand areas with high-resolution spatial data on physical properties, land use, energy, and demography. The grid topology is treated as a capacitated vehicle routing problem (CVRP) combined with a local search metaheuristics. We also consider the current planning principles for MV distribution networks, paying special attention to line congestion and voltage limit violations. In the modelling process, we included power flow calculations for validation. The resulting grid model datasets contain 3608 synthetic MV grids in high resolution, covering all of Germany and taking local characteristics into account. We compared the modelled networks with real network data. In terms of number of transformers and total cable length, we conclude that the method presented in this paper generates realistic grids that could be used to implement a cost-optimised electrical energy system.

Stability of Grid-Connected PV Inverters with Large Grid Impedance Variation

DEFF Research Database (Denmark)

Liserre, Marco; Teodorescu, Remus; Blaabjerg, Frede

2004-01-01

Photovoltaic (PV) inverters used in dispersed power generation of houses in the range of 1-5 kW are currently available from several manufactures. However, large grid impedance variation is challenging the control and the grid filter design in terms of stability. In fact the PV systems are well...... suited for loads connected in a great distance to the transformer (long wires) and the situation becomes even more difficult in low-developed remote areas characterized by low power transformers and long distribution wires with high grid impedance. Hence a theoretical analysis is needed because the grid...... impedance variation leads to dynamic and stability problems both in the low frequency range (around the current controller bandwidth frequency) as well as in the high frequency range (around the LCL-filter resonance frequency). In the low frequency range the possible variation of the impedance challenges...

TIGER: Turbomachinery interactive grid generation

Science.gov (United States)

Soni, Bharat K.; Shih, Ming-Hsin; Janus, J. Mark

1992-01-01

A three dimensional, interactive grid generation code, TIGER, is being developed for analysis of flows around ducted or unducted propellers. TIGER is a customized grid generator that combines new technology with methods from general grid generation codes. The code generates multiple block, structured grids around multiple blade rows with a hub and shroud for either C grid or H grid topologies. The code is intended for use with a Euler/Navier-Stokes solver also being developed, but is general enough for use with other flow solvers. TIGER features a silicon graphics interactive graphics environment that displays a pop-up window, graphics window, and text window. The geometry is read as a discrete set of points with options for several industrial standard formats and NASA standard formats. Various splines are available for defining the surface geometries. Grid generation is done either interactively or through a batch mode operation using history files from a previously generated grid. The batch mode operation can be done either with a graphical display of the interactive session or with no graphics so that the code can be run on another computer system. Run time can be significantly reduced by running on a Cray-YMP.

MaGate Simulator: A Simulation Environment for a Decentralized Grid Scheduler

Science.gov (United States)

Huang, Ye; Brocco, Amos; Courant, Michele; Hirsbrunner, Beat; Kuonen, Pierre

This paper presents a simulator for of a decentralized modular grid scheduler named MaGate. MaGate’s design emphasizes scheduler interoperability by providing intelligent scheduling serving the grid community as a whole. Each MaGate scheduler instance is able to deal with dynamic scheduling conditions, with continuously arriving grid jobs. Received jobs are either allocated on local resources, or delegated to other MaGates for remote execution. The proposed MaGate simulator is based on GridSim toolkit and Alea simulator, and abstracts the features and behaviors of complex fundamental grid elements, such as grid jobs, grid resources, and grid users. Simulation of scheduling tasks is supported by a grid network overlay simulator executing distributed ant-based swarm intelligence algorithms to provide services such as group communication and resource discovery. For evaluation, a comparison of behaviors of different collaborative policies among a community of MaGates is provided. Results support the use of the proposed approach as a functional ready grid scheduler simulator.

New grid-planning and certification approaches for the large-scale offshore-wind farm grid-connection systems

Energy Technology Data Exchange (ETDEWEB)

Heising, C.; Bartelt, R. [Avasition GmbH, Dortmund (Germany); Zadeh, M. Koochack; Lebioda, T.J.; Jung, J. [TenneT Offshore GmbH, Bayreuth (Germany)

2012-07-01

Stable operation of the offshore-wind farms (OWF) and stable grid connection under stationary and dynamic conditions are essential to achieve a stable public power supply. To reach this aim, adequate grid-planning and certification approaches are a major advantage. Within this paper, the fundamental characteristics of the offshore-wind farms and their grid-connection systems are given. The main goal of this research project is to study the stability of the offshore grid especially in terms of subharmonic stability for the likely future extension stage of the offshore grids i.e. having parallel connection of two or more HVDC links and for certain operating scenarios e.g. overload scenario. The current requirements according to the grid code are not the focus of this research project. The goal is to study and define potential additional grid code requirements, simulations, tests and grid planning methods for the future. (orig.)

Online Grid Measurement and ENS Detection for PV Inverter Running on Highly Inductive Grid

DEFF Research Database (Denmark)

Timbus, Adrian Vasile; Teodorescu, Remus; Blaabjerg, Frede

2004-01-01

Photovoltaic (PV) and other sources of renewable energy are being used increasingly in grid-connected systems, for which stronger power quality requirements are being issued. Continuous grid monitoring should be considered so as to provide safe connections and disconnections from the grid...

Non-Galerkin Coarse Grids for Algebraic Multigrid

Energy Technology Data Exchange (ETDEWEB)

Falgout, Robert D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Schroder, Jacob B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2014-06-26

Algebraic multigrid (AMG) is a popular and effective solver for systems of linear equations that arise from discretized partial differential equations. And while AMG has been effectively implemented on large scale parallel machines, challenges remain, especially when moving to exascale. Particularly, stencil sizes (the number of nonzeros in a row) tend to increase further down in the coarse grid hierarchy, and this growth leads to more communication. Therefore, as problem size increases and the number of levels in the hierarchy grows, the overall efficiency of the parallel AMG method decreases, sometimes dramatically. This growth in stencil size is due to the standard Galerkin coarse grid operator, $P^T A P$, where $P$ is the prolongation (i.e., interpolation) operator. For example, the coarse grid stencil size for a simple three-dimensional (3D) seven-point finite differencing approximation to diffusion can increase into the thousands on present day machines, causing an associated increase in communication costs. We therefore consider algebraically truncating coarse grid stencils to obtain a non-Galerkin coarse grid. First, the sparsity pattern of the non-Galerkin coarse grid is determined by employing a heuristic minimal “safe” pattern together with strength-of-connection ideas. Second, the nonzero entries are determined by collapsing the stencils in the Galerkin operator using traditional AMG techniques. The result is a reduction in coarse grid stencil size, overall operator complexity, and parallel AMG solve phase times.

NetJobs: A new approach to network monitoring for the Grid using Grid jobs

OpenAIRE

Pagano, Alfredo

2011-01-01

With grid computing, the far-fl�ung and disparate IT resources act as a single "virtual datacenter". Grid computing interfaces heterogeneous IT resources so they are available when and where we need them. Grid allows us to provision applications and allocate capacity among research and business groups that are geographically and organizationally dispersed. Building a high availability Grid is hold as the next goal to achieve: protecting against computer failures and site failures to avoid dow...

The International Symposium on Grids and Clouds and the Open Grid Forum

Science.gov (United States)

The International Symposium on Grids and Clouds 20111 was held at Academia Sinica in Taipei, Taiwan on 19th to 25th March 2011. A series of workshops and tutorials preceded the symposium. The aim of ISGC is to promote the use of grid and cloud computing in the Asia Pacific region. Over the 9 years that ISGC has been running, the programme has evolved to become more user community focused with subjects reaching out to a larger population. Research communities are making widespread use of distributed computing facilities. Linking together data centers, production grids, desktop systems or public clouds, many researchers are able to do more research and produce results more quickly. They could do much more if the computing infrastructures they use worked together more effectively. Changes in the way we approach distributed computing, and new services from commercial providers, mean that boundaries are starting to blur. This opens the way for hybrid solutions that make it easier for researchers to get their job done. Consequently the theme for ISGC2011 was the opportunities that better integrated computing infrastructures can bring, and the steps needed to achieve the vision of a seamless global research infrastructure. 2011 is a year of firsts for ISGC. First the title - while the acronym remains the same, its meaning has changed to reflect the evolution of computing: The International Symposium on Grids and Clouds. Secondly the programming - ISGC 2011 has always included topical workshops and tutorials. But 2011 is the first year that ISGC has been held in conjunction with the Open Grid Forum2 which held its 31st meeting with a series of working group sessions. The ISGC plenary session included keynote speakers from OGF that highlighted the relevance of standards for the research community. ISGC with its focus on applications and operational aspects complemented well with OGF's focus on standards development. ISGC brought to OGF real-life use cases and needs to be

Optimal scheduling for vehicle-to-grid operation with stochastic connection of plug-in electric vehicles to smart grid

International Nuclear Information System (INIS)

Jian, Linni; Zheng, Yanchong; Xiao, Xinping; Chan, C.C.

2015-01-01

Highlights: • A novel event-triggered scheduling scheme for vehicle-to-grid (V2G) operation is proposed. • New scheme can handle the uncertainty arising from stochastic connection of electric vehicles. • New scheme aims at minimizing the overall load variance of power grid by V2G operation. • Method to evaluate the performance of proposed scheme is elaborated and demonstrated. - Abstract: Vehicle-to-grid (V2G) operation of plug-in electric vehicles (PEVs) is attracting increasing attention since it can assist to improve the efficiency and reliability of power grid, as well as reduce the operating cost and greenhouse gas emission of electric vehicles. Within the scheme of V2G operation, PEVs are expected to serve as a novel distributed energy storage system (ESS) to help achieve the balance between supply and demand of power grid. One of the key difficulties concerning its practical implementation lies in that the availability of PEVs as ESS for grid remains highly uncertain due to their mobility as transportation tools. To address this issue, a novel event-triggered scheduling scheme for V2G operation based on the scenario of stochastic PEV connection to smart grid is proposed in this paper. Firstly, the mathematical model is formulated. Secondly, the preparation of input data for systematic evaluation is introduced and the case study is conducted. Finally, statistic analysis results demonstrate that our proposed V2G scheduling scheme can dramatically smooth out the fluctuation in power load profiles

Numerical solution of the full potential equation using a chimera grid approach

Science.gov (United States)

Holst, Terry L.

1995-01-01

A numerical scheme utilizing a chimera zonal grid approach for solving the full potential equation in two spatial dimensions is described. Within each grid zone a fully-implicit approximate factorization scheme is used to advance the solution one interaction. This is followed by the explicit advance of all common zonal grid boundaries using a bilinear interpolation of the velocity potential. The presentation is highlighted with numerical results simulating the flow about a two-dimensional, nonlifting, circular cylinder. For this problem, the flow domain is divided into two parts: an inner portion covered by a polar grid and an outer portion covered by a Cartesian grid. Both incompressible and compressible (transonic) flow solutions are included. Comparisons made with an analytic solution as well as single grid results indicate that the chimera zonal grid approach is a viable technique for solving the full potential equation.

Numerical Analysis for IFM Grid Effect on 5x5 Rods Bundle

International Nuclear Information System (INIS)

Kim, Seong Jin; Cha, Jeong Hun; Seo, Kyong Won; Kim, Tae Woo; Kwon, Hyuk; Hwang, Dae Hyun

2011-01-01

Generally, the fuel assembly consists of fuel rods, bottom and top grids, spacer grids, mixing vane, etc. The mixing vane with spacer grid is used to increase the thermal mixing between subchannels and to increase CHF(Critical Heat Flux). IFM(Intermediate Flow Mixer) grids are used to induce lateral flow between adjacent channels and are well-known as improving CHF, also. A numerical analysis using CFD code(ANSYS CFX, version 12.1) and subchannel code(MATRA-S) was conducted to investigate the influence of IFM grid on the subchannel temperature in 5x5 rods bundle with and without the IFM grid, thermohydraulically. In this study, the quantitative improvement of the mixing effect of the IFM grid is presented from the results of CFX and MATRA-S code. Moreover, capacity of predicting subchannel temperature of MATRA-S code is compared with CFX result

Wireless Communications in Smart Grid

Science.gov (United States)

Bojkovic, Zoran; Bakmaz, Bojan

Communication networks play a crucial role in smart grid, as the intelligence of this complex system is built based on information exchange across the power grid. Wireless communications and networking are among the most economical ways to build the essential part of the scalable communication infrastructure for smart grid. In particular, wireless networks will be deployed widely in the smart grid for automatic meter reading, remote system and customer site monitoring, as well as equipment fault diagnosing. With an increasing interest from both the academic and industrial communities, this chapter systematically investigates recent advances in wireless communication technology for the smart grid.

[Quantification of acetabular coverage in normal adult].

Science.gov (United States)

Lin, R M; Yang, C Y; Yu, C Y; Yang, C R; Chang, G L; Chou, Y L

1991-03-01

Quantification of acetabular coverage is important and can be expressed by superimposition of cartilage tracings on the maximum cross-sectional area of the femoral head. A practical Autolisp program on PC AutoCAD has been developed by us to quantify the acetabular coverage through numerical expression of the images of computed tomography. Thirty adults (60 hips) with normal center-edge angle and acetabular index in plain X ray were randomly selected for serial drops. These slices were prepared with a fixed coordination and in continuous sections of 5 mm in thickness. The contours of the cartilage of each section were digitized into a PC computer and processed by AutoCAD programs to quantify and characterize the acetabular coverage of normal and dysplastic adult hips. We found that a total coverage ratio of greater than 80%, an anterior coverage ratio of greater than 75% and a posterior coverage ratio of greater than 80% can be categorized in a normal group. Polar edge distance is a good indicator for the evaluation of preoperative and postoperative coverage conditions. For standardization and evaluation of acetabular coverage, the most suitable parameters are the total coverage ratio, anterior coverage ratio, posterior coverage ratio and polar edge distance. However, medial coverage and lateral coverage ratios are indispensable in cases of dysplastic hip because variations between them are so great that acetabuloplasty may be impossible. This program can also be used to classify precisely the type of dysplastic hip.

Fuel Cell Backup Power System for Grid Service and Micro-Grid in Telecommunication Applications: Preprint

Energy Technology Data Exchange (ETDEWEB)

Ma, Zhiwen [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Eichman, Joshua D [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kurtz, Jennifer M [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2018-03-22

This paper presents the feasibility and economics of using fuel cell backup power systems in telecommunication cell towers to provide grid services (e.g., ancillary services, demand response). The fuel cells are able to provide power for the cell tower during emergency conditions. This study evaluates the strategic integration of clean, efficient, and reliable fuel cell systems with the grid for improved economic benefits. The backup systems have potential as enhanced capability through information exchanges with the power grid to add value as grid services that depend on location and time. The economic analysis has been focused on the potential revenue for distributed telecommunications fuel cell backup units to provide value-added power supply. This paper shows case studies on current fuel cell backup power locations and regional grid service programs. The grid service benefits and system configurations for different operation modes provide opportunities for expanding backup fuel cell applications responsive to grid needs.

GRID Prototype for imagery processing in scientific applications

International Nuclear Information System (INIS)

Stan, Ionel; Zgura, Ion Sorin; Haiduc, Maria; Valeanu, Vlad; Giurgiu, Liviu

2004-01-01

The paper presents the results of our study which is part of the InGRID project. This project is supported by ROSA (ROmanian Space Agency). In this paper we will show the possibility to take images from the optical microscope through web camera. The images are then stored on the PC in Linux operating system and distributed to other clusters through GRID technology (using http, php, MySQL, Globus or AliEn systems). The images are provided from nuclear emulsions in the frame of Becquerel Collaboration. The main goal of the project InGRID is to actuate developing and deploying GRID technology for images technique taken from space, different application fields and telemedicine. Also it will create links with the same international projects which use advanced Grid technology and scalable storage solutions. The main topics proposed to be solved in the frame of InGRID project are: - Implementation of two GRID clusters, minimum level Tier 3; - Adapting and updating the common storage and processing computing facility; - Testing the middelware packages developed in the frame of this project; - Testbed production of the prototype; - Build-up and advertise the InGRID prototype in scientific community through current dissemination. InGRID Prototype developed in the frame of this project, will be used by partner institutes as deploying environment of the imaging applications the dynamical features of which will be defined by conditions of contract. Subsequent applications will be deployed by the partners of this project with governmental, nongovernmental and private institutions. (authors)

Application of a Steady Meandering River with Piers Using a Lattice Boltzmann Sub-Grid Model in Curvilinear Coordinate Grid

Directory of Open Access Journals (Sweden)

Liping Chen

2018-05-01

Full Text Available A sub-grid multiple relaxation time (MRT lattice Boltzmann model with curvilinear coordinates is applied to simulate an artificial meandering river. The method is based on the D2Q9 model and standard Smagorinsky sub-grid scale (SGS model is introduced to simulate meandering flows. The interpolation supplemented lattice Boltzmann method (ISLBM and the non-equilibrium extrapolation method are used for second-order accuracy and boundary conditions. The proposed model was validated by a meandering channel with a 180° bend and applied to a steady curved river with piers. Excellent agreement between the simulated results and previous computational and experimental data was found, showing that MRT-LBM (MRT lattice Boltzmann method coupled with a Smagorinsky sub-grid scale (SGS model in a curvilinear coordinates grid is capable of simulating practical meandering flows.

The DataGrid Project

CERN Document Server

Ruggieri, F

2001-01-01

An overview of the objectives and status of the DataGrid Project is presented, together with a brief introduction to the Grid metaphor and some references to the Grid activities and initiatives related to DataGrid. High energy physics experiments have always requested state of the art computing facilities to efficiently perform several computing activities related with the handling of large amounts of data and fairly large computing resources. Some of the ideas born inside the community to enhance the user friendliness of all the steps in the computing chain have been, sometimes, successfully applied also in other contexts: one bright example is the World Wide Web. The LHC computing challenge has triggered inside the high energy physics community, the start of the DataGrid Project. The objective of the project is to enable next generation scientific exploration requiring intensive computation and analysis of shared large-scale databases. (12 refs).

gCube Grid services

CERN Document Server

Andrade, Pedro

2008-01-01

gCube is a service-based framework for eScience applications requiring collaboratory, on-demand, and intensive information processing. It provides to these communities Virtual Research Environments (VREs) to support their activities. gCube is build on top of standard technologies for computational Grids, namely the gLite middleware. The software was produced by the DILIGENT project and will continue to be supported and further developed by the D4Science project. gCube reflects within its name a three-sided interpretation of the Grid vision of resource sharing: sharing of computational resources, sharing of structured data, and sharing of application services. As such, gCube embodies the defining characteristics of computational Grids, data Grids, and virtual data Grids. Precisely, it builds on gLite middleware for managing distributed computations and unstructured data, includes dedicated services for managing data and metadata, provides services for distributed information retrieval, allows the orchestration...

Research on wind power grid-connected operation and dispatching strategies of Liaoning power grid

Science.gov (United States)

Han, Qiu; Qu, Zhi; Zhou, Zhi; He, Xiaoyang; Li, Tie; Jin, Xiaoming; Li, Jinze; Ling, Zhaowei

2018-02-01

As a kind of clean energy, wind power has gained rapid development in recent years. Liaoning Province has abundant wind resources and the total installed capacity of wind power is in the forefront. With the large-scale wind power grid-connected operation, the contradiction between wind power utilization and peak load regulation of power grid has been more prominent. To this point, starting with the power structure and power grid installation situation of Liaoning power grid, the distribution and the space-time output characteristics of wind farm, the prediction accuracy, the curtailment and the off-grid situation of wind power are analyzed. Based on the deep analysis of the seasonal characteristics of power network load, the composition and distribution of main load are presented. Aiming at the problem between the acceptance of wind power and power grid adjustment, the scheduling strategies are given, including unit maintenance scheduling, spinning reserve, energy storage equipment settings by the analysis of the operation characteristics and the response time of thermal power units and hydroelectric units, which can meet the demand of wind power acceptance and provide a solution to improve the level of power grid dispatching.

Multi-Grid Lanczos

Directory of Open Access Journals (Sweden)

Clark M. A.

2018-01-01

Full Text Available We present a Lanczos algorithm utilizing multiple grids that reduces the memory requirements both on disk and in working memory by one order of magnitude for RBC/UKQCD’s 48I and 64I ensembles at the physical pion mass. The precision of the resulting eigenvectors is on par with exact deflation.

Procedure on the Impact Characteristic Test for the One-sided and Thru-grid Spacer Grid

International Nuclear Information System (INIS)

Yoon, Kyung Ho; Kim, Jae Yong; Lee, Kang Hee; Song, Kee Nam

2006-09-01

In order to perform the one-sided and the through-grid impact tests for a new developed spacer grid, the drop type impact test machines were established. The dynamic impact test is to get some basic data for accident analysis such as impact strength, stiffness, and coefficient of the restitution. Furthermore, these developed test methods and procedures will be qualified standard for increasing the reliability of the test results. Chapter 2 provides an introduction to the test facilities and instrumentations. Chapter 3 describes on how spacer grid and the single span fuel assembly specimen will be prepared. In addition to this, how to set up these testing machines. Chapter 4 illustrates detail test procedure on how to acquire impact signal of the two kinds of the specimen. Chapter 5 deals with signal processing and analysis for the test data. Finally, chapter 6 summarise the overall test procedure and the test method

Optimizing solar-cell grid geometry

Science.gov (United States)

Crossley, A. P.

1969-01-01

Trade-off analysis and mathematical expressions calculate optimum grid geometry in terms of various cell parameters. Determination of the grid geometry provides proper balance between grid resistance and cell output to optimize the energy conversion process.

Grid-friendly wind power systems based on the synchronverter technology

International Nuclear Information System (INIS)

Zhong, Qing-Chang; Ma, Zhenyu; Ming, Wen-Long; Konstantopoulos, George C.

2015-01-01

Highlights: • A grid-friendly wind power system that uses the synchronverter technology is proposed. • Both the rotor-side and the grid-side converters act as synchronverters. • The complete generator–motor–generator system improves the performance under grid faults. • Real-time digital simulation results verify the effectiveness of the proposed method. - Abstract: Back-to-back PWM converters are becoming a realistic alternative to conventional converters in high-power wind power applications. In this paper, a control strategy based on the synchronverter technology is proposed for back-to-back PWM converters. Both converters are run as synchronverters, which are mathematically equivalent to the conventional synchronous generators. The rotor-side converter is responsible for maintaining the DC link voltage and the grid-side converter is responsible for the maximum power point tracking (MPPT). As the two converters are operated using the synchronverter technology, the formed wind power system becomes more friendly to the grid. Extensive real-time digital simulation results are presented to verify the effectiveness of the proposed method under normal operation and grid-fault scenarios

Communication and Networking in Smart Grids

CERN Document Server

Xiao, Yang

2012-01-01

Appropriate for researchers, practitioners, and students alike, Communication and Networking in Smart Grids presents state-of-the-art approaches and novel technologies for communication networks in smart grids. It explains how contemporary grid networks are developed and deployed and presents a collection of cutting-edge advances to help improve current practice. Prominent researchers working on smart grids and in related fields around the world explain the fundamental aspects and applications of smart grids. Describing the role that communication and networking will play in future smart grids

Finite volume methods for the incompressible Navier-Stokes equations on unstructured grids

Energy Technology Data Exchange (ETDEWEB)

Meese, Ernst Arne

1998-07-01

Most solution methods of computational fluid dynamics (CFD) use structured grids based on curvilinear coordinates for compliance with complex geometries. In a typical industry application, about 80% of the time used to produce the results is spent constructing computational grids. Recently the use of unstructured grids has been strongly advocated. For unstructured grids there are methods for generating them automatically on quite complex domains. This thesis focuses on the design of Navier-Stokes solvers that can cope with unstructured grids and ''low quality grids'', thus reducing the need for human intervention in the grid generation.

Spurious effects of electron emission from the grids of a retarding field analyser on secondary electron emission measurements. Results on a (111) copper single crystal

International Nuclear Information System (INIS)

Pillon, J.; Roptin, D.; Cailler, M.

1976-01-01

Spurious effects of a four grid retarding field analyzer were studied for low energy secondary electron measurements. Their behavior was investigated and two peaks in the energy spectrum were interpreted as resulting from tertiary electrons from the grids. It was shown that the true secondary electron peak has to be separated from these spurious peaks. The spectrum and the yields sigma and eta obtained for a Cu(111) crystal after a surface cleanness control by Auger spectroscopy are given

The play grid

DEFF Research Database (Denmark)

Fogh, Rune; Johansen, Asger

2013-01-01

In this paper we propose The Play Grid, a model for systemizing different play types. The approach is psychological by nature and the actual Play Grid is based, therefore, on two pairs of fundamental and widely acknowledged distinguishing characteristics of the ego, namely: extraversion vs. intro...

Synchronization of grid-connected renewable energy sources under highly distorted voltages and unbalanced grid faults

DEFF Research Database (Denmark)

Hadjidemetriou, Lenos; Kyriakides, Elias; Blaabjerg, Frede

2013-01-01

Renewable energy sources require accurate and appropriate performance not only under normal grid operation but also under abnormal and faulty grid conditions according to the modern grid codes. This paper proposes a novel phase-locked loop algorithm (MSHDC-PLL), which can enable the fast...... and dynamic synchronization of the interconnected renewable energy system under unbalanced grid faults and under highly harmonic distorted voltage. The outstanding performance of the suggested PLL is achieved by implementing an innovative multi-sequence/harmonic decoupling cell in order to dynamically cancel...... renewable energy systems. Therefore, the performance of the new PLL can increase the quality of the injected power under abnormal conditions and in addition enable the renewable energy systems to provide the appropriate support to the grid under balanced and unbalanced grid faults....

Additional Security Considerations for Grid Management

Science.gov (United States)

Eidson, Thomas M.

2003-01-01

The use of Grid computing environments is growing in popularity. A Grid computing environment is primarily a wide area network that encompasses multiple local area networks, where some of the local area networks are managed by different organizations. A Grid computing environment also includes common interfaces for distributed computing software so that the heterogeneous set of machines that make up the Grid can be used more easily. The other key feature of a Grid is that the distributed computing software includes appropriate security technology. The focus of most Grid software is on the security involved with application execution, file transfers, and other remote computing procedures. However, there are other important security issues related to the management of a Grid and the users who use that Grid. This note discusses these additional security issues and makes several suggestions as how they can be managed.

Study of Swept Angle Effects on Grid Fins Aerodynamics Performance

Science.gov (United States)

Faza, G. A.; Fadillah, H.; Silitonga, F. Y.; Agoes Moelyadi, Mochamad

2018-04-01

Grid fin is an aerodynamic control surface that usually used on missiles and rockets. In the recent several years many researches have conducted to develop a more efficient grid fins. There are many possibilities of geometric combination could be done to improve aerodynamics characteristic of a grid fin. This paper will only discuss about the aerodynamics characteristics of grid fins compared by another grid fins with different swept angle. The methodology that used to compare the aerodynamics is Computational Fluid Dynamics (CFD). The result of this paper might be used for future studies to answer our former question or as a reference for related studies.

GridPP returns to CERN

CERN Document Server

Neasan O'Neill

2011-01-01

In early September, GridPP, the collaboration that manages the UK’s contribution to the worldwide LHC Computing Grid (wLCG), celebrated a decade of work by holding its twenty-seventh collaboration meeting at CERN.   Officially launched in September 2001, GridPP was one of the original partners in wLCG, funding much of the early work at CERN. Over the last decade GridPP has gone from a mere proposal to almost 30,000 CPUs working for researchers scattered across the globe. Twice a year, GridPP meets to discuss the progress and future plans of the community and this year, for the first time since 2004, decamped to CERN for this biannual meeting on the theme “GridPP in the International Context”. The main meeting was held over 2 days in the IT auditorium and was the perfect opportunity to have contributions from experts based at CERN, alongside those from within GridPP. Opening with a welcome from Frederic Hemmer, Head of the IT Department at CERN, the meeting began with...

Observability of Low Voltage grids

DEFF Research Database (Denmark)

Martin-Loeches, Ruben Sánchez; Iov, Florin; Kemal, Mohammed Seifu

2017-01-01

Low Voltage (LV) distribution power grids are experiencing a transformation from a passive to a more active role due to the increasing penetration of distributed generation, heat pumps and electrical vehicles. The first step towards a smarter operation of LV electrical systems is to provide grid ...... an updated state of the art on DSSE-AMI based, adaptive data collection techniques and database management system types. Moreover, the ongoing Danish RemoteGRID project is presented as a realistic case study.......Low Voltage (LV) distribution power grids are experiencing a transformation from a passive to a more active role due to the increasing penetration of distributed generation, heat pumps and electrical vehicles. The first step towards a smarter operation of LV electrical systems is to provide grid....... It becomes unrealistic to provide near real time full observability of the LV grid by applying Distribution System State Estimation (DSSE) utilizing the classical data collection and storage/preprocessing techniques. This paper investigates up-todate the observability problem in LV grids by providing...

Workshop on Future Generation Grids

CERN Document Server

Laforenza, Domenico; Reinefeld, Alexander

2006-01-01

The Internet and the Web continue to have a major impact on society. By allowing us to discover and access information on a global scale, they have created entirely new businesses and brought new meaning to the term surf. In addition, however, we want processing, and increasingly, we want collaborative processing within distributed teams. This need has led to the creation of the Grid - an infrastructure that enables us to share capabilities, and integrate services and resources within and across enterprises. "Future Generation Grids" is the second in the "CoreGRID" series. This edited volume brings together contributed articles by scientists and researchers in the Grid community in an attempt to draw a clearer picture of the future generation Grids. This book also identifies some of the most challenging problems on the way to achieving the invisible Grid ideas

Communication technologies in smart grid

Directory of Open Access Journals (Sweden)

Miladinović Nikola

2013-01-01

Full Text Available The role of communication technologies in Smart Grid lies in integration of large number of devices into one telecommunication system. This paper provides an overview of the technologies currently in use in electric power grid, that are not necessarily in compliance with the Smart Grid concept. Considering that the Smart Grid is open to the flow of information in all directions, it is necessary to provide reliability, protection and security of information.

Grid and Entrepreneurship Workshop

CERN Multimedia

2006-01-01

The CERN openlab is organising a special workshop about Grid opportunities for entrepreneurship. This one-day event will provide an overview of what is involved in spin-off technology, with a special reference to the context of computing and data Grids. Lectures by experienced entrepreneurs will introduce the key concepts of entrepreneurship and review, in particular, the industrial potential of EGEE (the EU co-funded Enabling Grids for E-sciencE project, led by CERN). Case studies will be given by CEOs of European start-ups already active in the Grid and computing cluster area, and regional experts will provide an overview of efforts in several European regions to stimulate entrepreneurship. This workshop is designed to encourage students and researchers involved or interested in Grid technology to consider the entrepreneurial opportunities that this technology may create in the coming years. This workshop is organized as part of the CERN openlab student programme, which is co-sponsored by CERN, HP, ...

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

Energy Technology Data Exchange (ETDEWEB)

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.

Estimation of effective elastic constants for grid plate

International Nuclear Information System (INIS)

Shibanuma, Kiyoshi; Kuriyama, Masaaki; Okumura, Yoshikazu

1980-07-01

This article contains a method of estimation for the effective elastic constants of a grid plate, which is a flat perforated plate with pipes for cooling. The elastic constants of the grid plate are formulated for two symmetric axes. In the case of using OFCu(E 0 = 12500 kg/mm 2 , ν 0 = 0.34) as the material of the grid, the results are given as follows. E sub(L) = 3180 kg/mm 2 , E sub(T) = 3860 kg/mm 2 upsilon sub(LT) = 0.12, upsilon sub(TL) = 0.15 (author)

Nuclear reactor seismic fuel assembly grid

International Nuclear Information System (INIS)

Anthony, A.J.

1977-01-01

The strength of a nuclear reactor fuel assembly is enhanced by increasing the crush strength of the zircaloy spacer grids which locate and support the fuel elements in the fuel assembly. Increased resistance to deformation as a result of laterally directed forces is achieved by increasing the section modulus of the perimeter strip through bending the upper and lower edges thereof inwardly. The perimeter strip is further rigidized by forming, in the central portion thereof, dimples which extend inwardly with respect to the fuel assembly. The integrity of the spacer grid may also be enhanced by providing back-up arches for some or all of the integral fuel element locating springs and the strength of the fuel assembly may be further enhanced by providing, intermediate its ends, a steel seismic grid. 13 claims, 6 figures

Technology Roadmaps: Smart Grids

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-07-01

The development of Technology Roadmaps: Smart Grids -- which the IEA defines as an electricity network that uses digital and other advanced technologies to monitor and manage the transport of electricity from all generation sources to meet the varying electricity demands of end users -- is essential if the global community is to achieve shared goals for energy security, economic development and climate change mitigation. Unfortunately, existing misunderstandings of exactly what smart grids are and the physical and institutional complexity of electricity systems make it difficult to implement smart grids on the scale that is needed. This roadmap sets out specific steps needed over the coming years to achieve milestones that will allow smart grids to deliver a clean energy future.

Delaunay Triangulation as a New Coverage Measurement Method in Wireless Sensor Network

Science.gov (United States)

Chizari, Hassan; Hosseini, Majid; Poston, Timothy; Razak, Shukor Abd; Abdullah, Abdul Hanan

2011-01-01

Sensing and communication coverage are among the most important trade-offs in Wireless Sensor Network (WSN) design. A minimum bound of sensing coverage is vital in scheduling, target tracking and redeployment phases, as well as providing communication coverage. Some methods measure the coverage as a percentage value, but detailed information has been missing. Two scenarios with equal coverage percentage may not have the same Quality of Coverage (QoC). In this paper, we propose a new coverage measurement method using Delaunay Triangulation (DT). This can provide the value for all coverage measurement tools. Moreover, it categorizes sensors as ‘fat’, ‘healthy’ or ‘thin’ to show the dense, optimal and scattered areas. It can also yield the largest empty area of sensors in the field. Simulation results show that the proposed DT method can achieve accurate coverage information, and provides many tools to compare QoC between different scenarios. PMID:22163792

Securing the smart grid information exchange

Energy Technology Data Exchange (ETDEWEB)

Fries, Steffen; Falk, Rainer [Siemens AG, Corporate Technology, Muenchen (Germany)

2012-07-01

The smart grid is based on information exchange between various stakeholders using open communication technologies, to control the physical electric grid through the information grid. Protection against cyber attacks is essential to ensure a reliable operation of the smart grid. This challenge is addressed by various regulatory, standardization, and research activities. After giving an overview of the security demand of a smart grid, existing and appearing standardization activities are described. (orig.)

Monitoring the EGEE/WLCG grid services

International Nuclear Information System (INIS)

Duarte, A; Nyczyk, P; Retico, A; Vicinanza, D

2008-01-01

Grids have the potential to revolutionise computing by providing ubiquitous, on demand access to computational services and resources. They promise to allow for on demand access and composition of computational services provided by multiple independent sources. Grids can also provide unprecedented levels of parallelism for high-performance applications. On the other hand, grid characteristics, such as high heterogeneity, complexity and distribution create many new technical challenges. Among these technical challenges, failure management is a key area that demands much progress. A recent survey revealed that fault diagnosis is still a major problem for grid users. When a failure appears at the user screen, it becomes very difficult for the user to identify whether the problem is in the application, somewhere in the grid middleware, or even lower in the fabric that comprises the grid. In this paper we present a tool able to check if a given grid service works as expected for a given set of users (Virtual Organisation) on the different resources available on a grid. Our solution deals with grid services as single components that should produce an expected output to a pre-defined input, what is quite similar to unit testing. The tool, called Service Availability Monitoring or SAM, is being currently used by several different Virtual Organizations to monitor more than 300 grid sites belonging to the largest grids available today. We also discuss how this tool is being used by some of those VOs and how it is helping in the operation of the EGEE/WLCG grid

On temperature spectra in grid turbulence

International Nuclear Information System (INIS)

Jayesh; Tong, C.; Warhaft, Z.

1994-01-01

This paper reports wind tunnel measurements of passive temperature spectra in decaying grid generated turbulence both with and without a mean transverse temperature gradient. The measurements cover a turbulence Reynolds number range 60 l 3/4 l . The remarkably low Reynolds number onset (Re l ∼70) of Kolmogorov--Obukhov--Corrsin scaling in isotropic grid turbulence is contrasted to the case of scalars in (anisotropic) shear flows where KOC scaling only appears at very high-Reynolds numbers (Re l ∼10 5 ). It is also shown that when the temperature fluctuations are inserted very close to the grid in the absence of a gradient (by means of a mandoline), the temperature spectrum behaves in a similar way to the linear gradient case, i.e., a spectrum with a scaling exponent close to -5/3 is observed, a result noted earlier in heated grid experiments. However, when the scalar is inserted farther downstream of the grid (in the fully developed turbulence), the spectrum has a scaling region of -1.3 and its dilation with Re is less well defined than for the other cases. The velocity spectrum is also shown to have a scaling region, of slope -1.3, and its onset occurs at higher Reynolds number than for the case of the scalar experiments that exhibit the KOC scaling

Dynamic overset grid communication on distributed memory parallel processors

Science.gov (United States)

Barszcz, Eric; Weeratunga, Sisira K.; Meakin, Robert L.

1993-01-01

A parallel distributed memory implementation of intergrid communication for dynamic overset grids is presented. Included are discussions of various options considered during development. Results are presented comparing an Intel iPSC/860 to a single processor Cray Y-MP. Results for grids in relative motion show the iPSC/860 implementation to be faster than the Cray implementation.

Frequency Adaptive Repetitive Control of Grid-Tied Single-Phase PV Inverters

DEFF Research Database (Denmark)

Zhou, Keliang; Yang, Yongheng; Blaabjerg, Frede

2015-01-01

. This paper thus explores a frequency adaptive repetitive control strategy for grid converters, which employs fractional delay filters in order to adapt to the change of the grid frequency. Case studies with experimental results of a single-phase grid-connected PV inverter system are provided to verify...

Numerical analysis of the spacer grids' compression strength

Energy Technology Data Exchange (ETDEWEB)

Schettino, C.F.M.; Gouvea, J.P.; Medeiros, N., E-mail: carlosschettino@inb.gov.br, E-mail: jpg@metal.eeimvr.uff.br [Universidade Federal Fluminense (UFF), Volta Redonda, RJ (Brazil). Programa de Engenharia Metalurgica

2013-07-01

Among the components of the fuel assembly, the spacer grids play an important structural role during the energy generation process, mainly for their requirement to have enough structural strength to withstand lateral impact loads, due to fuel assembly shipping/handling and due to forces outcome from postulated accidents (earthquake and LOCA). This requirement ensures a proper geometry for cooling and for guide thimble straightness in the fuel assembly. In this way, the understanding of the macroscopic mechanical behavior of this component becomes essential even to any subsequent geometrical modifications to optimize the flue assemblies' structural behavior. In the present work, three-dimensional finite element models destined to provide consistent predictions of 16X16-type spacer grids lateral strength were proposed. Firstly, buckling tests based on results available in the literature were performed to establish a methodology for spacer grid finite element-based modeling. The, by considering a spacer grid interesting geometry and some possible variations associated to its fabrication, tolerance, the proposed numerical models were submitted to compression conditions to calculate the buckling force. Also, these models were validated for comparison with experimental buckling load results. Comparison of buckling predictions combined to observations of actual and simulated deformed spacer grids geometries permitted to verify the consistency and applicability of the proposed models. Thus, these numerical results show a good agreement between the and the experimental results. (author)

On-grid and Off-grid Operation of Multi-Input Single-Output DC/DC Converter based Fuel Cell Generation System

Directory of Open Access Journals (Sweden)

Noroozian

2009-06-01

Full Text Available This paper presents the modeling and simulation of a proton exchange membrane fuel cell (PEMFC generation system for off-grid and on-grid operation and configuration. A fuel cell DG system consists of a fuel cell power plant, a DC/DC converter and a DC/AC inverter. The dynamic model for fuel cell array and its power electronic interfacing are presented also a multi-input single output (MISO DC/DC converter and its control scheme is proposed and analyzed. This DC/DC converter is capable of interfacing fuel cell arrays to the DC/AC inverter. Also the mathematical model of the inverter is obtained by using average technique. Then the novel control strategy of DC/AC inverter for different operating conditions is demonstrated. The simulation results show the effectiveness of the suggested control systems under both on-grid and off-grid operation modes.

Precision grid and hand motion for accurate needle insertion in brachytherapy

International Nuclear Information System (INIS)

McGill, Carl S.; Schwartz, Jonathon A.; Moore, Jason Z.; McLaughlin, Patrick W.; Shih, Albert J.

2011-01-01

Purpose: In prostate brachytherapy, a grid is used to guide a needle tip toward a preplanned location within the tissue. During insertion, the needle deflects en route resulting in target misplacement. In this paper, 18-gauge needle insertion experiments into phantom were performed to test effects of three parameters, which include the clearance between the grid hole and needle, the thickness of the grid, and the needle insertion speed. Measurement apparatus that consisted of two datum surfaces and digital depth gauge was developed to quantify needle deflections. Methods: The gauge repeatability and reproducibility (GR and R) test was performed on the measurement apparatus, and it proved to be capable of measuring a 2 mm tolerance from the target. Replicated experiments were performed on a 2 3 factorial design (three parameters at two levels) and analysis included averages and standard deviation along with an analysis of variance (ANOVA) to find significant single and two-way interaction factors. Results: Results showed that grid with tight clearance hole and slow needle speed increased precision and accuracy of needle insertion. The tight grid was vital to enhance precision and accuracy of needle insertion for both slow and fast insertion speed; additionally, at slow speed the tight, thick grid improved needle precision and accuracy. Conclusions: In summary, the tight grid is important, regardless of speed. The grid design, which shows the capability to reduce the needle deflection in brachytherapy procedures, can potentially be implemented in the brachytherapy procedure.

DIGRD: an interactive grid generating program

International Nuclear Information System (INIS)

Foote, H.P.; Rice, W.A.; Kincaid, C.T.

1982-11-01

Pacific Northwest Laboratory has completed the development and documentation of an interactive grid generating program (DIGRD, digitize grid). This program is designed to rapidly generate or modify grids necessary for the unsaturated flow code TRUST. In addition to the code, a user's manual was prepared. Unfortunately, the computer hardware that comprises the PNL interactive graphics capability is unique. Direct technology transfer is not possible, therefore, this report is intended to convey the utility of interactive graphics in supplying a grid generating capability. DIGRD has already been effectively used in the preparation of grids for the analysis of leachate movement from uranium mill tailings. The principal conclusion is that the interactive graphics employed in DIGRD are useful and economical in the development of complex grids. Grid generation activities that previously took between a half- and a full-man month can now be completed in less than a week. DIGRD users have recommended development of an uniform grid of either rectangles or equilateral triangles, which could be superimposed on any domain and then adjusted through the DIGRD program to match the boundaries of a tailings disposal facility. This improvement to the DIGRD package could further reduce the effort in grid generation while providing more optimal grids

Usability and Interoperability Improvements for an EASE-Grid 2.0 Passive Microwave Data Product Using CF Conventions

Science.gov (United States)

Hardman, M.; Brodzik, M. J.; Long, D. G.

2017-12-01

Beginning in 1978, the satellite passive microwave data record has been a mainstay of remote sensing of the cryosphere, providing twice-daily, near-global spatial coverage for monitoring changes in hydrologic and cryospheric parameters that include precipitation, soil moisture, surface water, vegetation, snow water equivalent, sea ice concentration and sea ice motion. Historical versions of the gridded passive microwave data sets were produced as flat binary files described in human-readable documentation. This format is error-prone and makes it difficult to reliably include all processing and provenance. Funded by NASA MEaSUREs, we have completely reprocessed the gridded data record that includes SMMR, SSM/I-SSMIS and AMSR-E. The new Calibrated Enhanced-Resolution Brightness Temperature (CETB) Earth System Data Record (ESDR) files are self-describing. Our approach to the new data set was to create netCDF4 files that use standard metadata conventions and best practices to incorporate file-level, machine- and human-readable contents, geolocation, processing and provenance metadata. We followed the flexible and adaptable Climate and Forecast (CF-1.6) Conventions with respect to their coordinate conventions and map projection parameters. Additionally, we made use of Attribute Conventions for Dataset Discovery (ACDD-1.3) that provided file-level conventions with spatio-temporal bounds that enable indexing software to search for coverage. Our CETB files also include temporal coverage and spatial resolution in the file-level metadata for human-readability. We made use of the JPL CF/ACDD Compliance Checker to guide this work. We tested our file format with real software, for example, netCDF Command-line Operators (NCO) power tools for unlimited control on spatio-temporal subsetting and concatenation of files. The GDAL tools understand the CF metadata and produce fully-compliant geotiff files from our data. ArcMap can then reproject the geotiff files on-the-fly and work

SuperGrid or SmartGrid: Competing strategies for large-scale integration of intermittent renewables?

DEFF Research Database (Denmark)

Blarke, Morten; M. Jenkins, Bryan

2013-01-01

This paper defines and compares two strategies for integrating intermittent renewables: SuperGrid and SmartGrid. While conventional energy policy suggests that these strategies may be implemented alongside each other, the paper identifies significant technological and socio-economic conflicts...... of interest between the two. The article identifies differences between a domestic strategy for the integration of intermittent renewables, vis-à-vis the SmartGrid, and a cross-system strategy, vis-à-vis the SuperGrid. Policy makers and transmission system operators must understand the need for both...... a paradigmatic case study from West Denmark which supports the hypothesis that these strategies are mutually exclusive. The case study shows that increasing cross-system transmission capacity jeopardizes the feasibility of SmartGrid technology investments. A political effort is required for establishing...

Gridded Population of the World, Version 3 (GPWv3): Population Count Grid

Data.gov (United States)

National Aeronautics and Space Administration — Gridded Population of the World, Version 3 (GPWv3) consists of estimates of human population for the years 1990, 1995, and 2000 by 2.5 arc-minute grid cells and...

Three-Phase Grid-Connected of Photovoltaic Generator Using Nonlinear Control

DEFF Research Database (Denmark)

Yahya, A.; El Fadil, H.; Guerrero, Josep M.

2014-01-01

This paper proposes a nonlinear control methodology for three phase grid connected of PV generator. It consists of a PV arrays; a voltage source inverter, a grid filter and an electric grid. The controller objectives are threefold: i) ensuring the Maximum power point tracking (MPPT) in the side...... stability analysis and simulation results that the proposed controller meets all the objectives....

Smart Grid: Smart Customer Policy Needs

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-07-01

In September 2010, the International Energy Agency (IEA) held a workshop on the regulatory, market and consumer policies necessary to ensure that smart grids are deployed with adequate consideration of their risks and benefits to all stakeholders. This was one of several workshops that brought together energy providers, network operators, technology developers, regulators, customers and government policy makers to discuss smart grid technology and policy. The Smart Grid - Smart Customer Policies workshop allowed stakeholders to: gain a perspective on key issues and barriers facing early deployment of smart grids; hear expert opinion on regulatory, consumer and market challenges to smart grids; discuss smart grid-smart customer policy priorities; and build consensus on the technology and policy ingredients needed for customer-friendly smart grid deployments. Drawing on workshop discussions, the following paper lays out a logical framework to maximise the benefits and minimise the risks that smart grids pose for customers. The paper also describes key policy research questions that will guide future IEA research on this topic.

Production grid systems and their programming

CERN Document Server

Kacsuk, P; Stefan, P

2004-01-01

Summary form only given. There are a large variety of grid test-beds that can be used for experimental purposes by a small community. However, the number of production grid systems that can be used as a service for a large community is very limited. The current tutorial provides introduction to three of these very few production grid systems. They represent different models and policies of using grid resources and hence understanding and comparing them is an extremely useful exercise to everyone interested in grid technology. The Hungarian ClusterGrid infrastructure connects clusters during the nights and weekends. These clusters are used during the day for educational purposes at the Hungarian universities and polytechnics. Therefore, a unique feature of this grid is the switching mechanism by which the day time and night time working modes are loaded to the computers. In order to manage the system as a production, one, the system is homogeneous, all the machines should install the same grid software package...

Analyses and Forecasting of Smart Grid Technological Dynamics

Directory of Open Access Journals (Sweden)

I. V. Danilin

2017-01-01

Full Text Available Purpose: this paper analyzes and forecasts medium- to long-term dynamics of Smart Grid technology developments considering both patent activity and socio-economic (demand-side issues and requirements of economy and power system factors. Methods: for the analysis of Smart Grid patent data (IIP, USPTO, and WIPO patent databases used we apply syntactic semantic analysis of texts in natural languages and logistic curve-based method. We propose Exactus Patent system for intelligent full-text search and analysis of patents (results verified with Thomson Innovation and TotalPatent patent search systems. For interpretation of revealed dynamics and forecasting of future conditions we identify key long-term socio-economic factors drivers for Smart Grid development. Elements of C. Christensen (disruptive innovations and G. Dosi (technological trajectories theories were applied. Results: the study reveals a fast technological transformation within the Smart Grid domain due to the long-term socio-economic factors such as rise of renewables; energy efficiency and energy security issues; environmental constraints and shift of values; requirements for accelerated grid construction (in developing economies and grid modernization (in developed ones; ongoing economy-wide digitalization. Due to the limited economic effects of Smart Grid roll-outs (considering major requirements of economic agents and society and considering progressions of patent dynamics, authors forecasts technology stagnation (in terms of number of patents growth by the end of 2010-s as end of Gartner`s hype development stage. Conclusions and Relevance: a foreseen change in dynamics of Smart Grid technology development is interpreted as a manifestation of sinusoidal fluctuations in technology development for disruptive technologies (supported with OECD data. A longer cycle (in comparison with other disruptive technologies is interpreted as consequence of technology and industry specifics

The experiment of grid characteristics for high-voltage radiography of chest

International Nuclear Information System (INIS)

Kim, Jung Min; Ahn, Bong Seon

1992-01-01

Grids can improve the diagnostic quality of chest radiography by trapping the greater part of scattered radiation thus providing more detailed chest radiographic images. It is most effective method of reduce the scatter ratio but must increase the expour factor. The benefit of use of grid is improve the contrast and the loss is increase of patient dose. In chest radiography especially hard quality high voltage radiography it will have to be considered to select the optimum grid with view point of benefit and loss. In this experiment, auther got some result of characteristics about 4 different grids with film method. 1. There was no difference the scatter ratio in case of no grid and the scatter ratio was about 60 % 2. 16 : 1 grid was excellent of scatter reduction factor in high voltage chest radiography, next was 10 : 1, CROSS, MICRO FINE grid have low scatter reduction rate compare to 16:1,10:1 grid. 3. The bucky factor of CROSS grid in accordance of kVp was find out the highest in 4 grids, on the contrary 10 : 1 grid was profitable to the. exposure does. 4. With careful consideration in the point of scatter reduction rate and bucky factor, auther suggest the 10 : 1 linear grid on the use of chest radiography in 80∼120 kVp, 16 : 1 grid in 120∼140 kVp

Interoperability and HealthGRID.

Science.gov (United States)

Bescos, C; Schmitt, D; Kass, J; García-Barbero, M; Kantchev, P

2005-01-01

GRID technology, with initiatives like the GGF, will have the potential to allow both competition and interoperability not only among applications and toolkits, but also among implementations of key services. The pyramid of eHealth interoperability should be achieved from standards in communication and data security, storage and processing, to the policy initiatives, including organizational protocols, financing procedures, and legal framework. The open challenges for GRID use in clinical fields illustrate the potential of the combination of grid technologies with medical routine into a wider interoperable framework. The Telemedicine Alliance is a consortium (ESA, WHO and ITU), initiated in 2002, in building a vision for the provision of eHealth to European citizens by 2010. After a survey with more that 50 interviews of experts, interoperability was identified as the main showstopper to eHealth implementation. There are already several groups and organizations contributing to standardization. TM-Alliance is supporting the "e-Health Standardization Coordination Group" (eHSCG). It is now, in the design and development phase of GRID technology in Health, the right moment to act with the aim of achieving an interoperable and open framework. The Health area should benefit from the initiatives started at the GGF in terms of global architecture and services definitions, as well as from the security and other web services applications developed under the Internet umbrella. There is a risk that existing important results of the standardization efforts in this area are not taken up simply because they are not always known.

Intelligent and robust optimization frameworks for smart grids

Science.gov (United States)

Dhansri, Naren Reddy

A smart grid implies a cyberspace real-time distributed power control system to optimally deliver electricity based on varying consumer characteristics. Although smart grids solve many of the contemporary problems, they give rise to new control and optimization problems with the growing role of renewable energy sources such as wind or solar energy. Under highly dynamic nature of distributed power generation and the varying consumer demand and cost requirements, the total power output of the grid should be controlled such that the load demand is met by giving a higher priority to renewable energy sources. Hence, the power generated from renewable energy sources should be optimized while minimizing the generation from non renewable energy sources. This research develops a demand-based automatic generation control and optimization framework for real-time smart grid operations by integrating conventional and renewable energy sources under varying consumer demand and cost requirements. Focusing on the renewable energy sources, the intelligent and robust control frameworks optimize the power generation by tracking the consumer demand in a closed-loop control framework, yielding superior economic and ecological benefits and circumvent nonlinear model complexities and handles uncertainties for superior real-time operations. The proposed intelligent system framework optimizes the smart grid power generation for maximum economical and ecological benefits under an uncertain renewable wind energy source. The numerical results demonstrate that the proposed framework is a viable approach to integrate various energy sources for real-time smart grid implementations. The robust optimization framework results demonstrate the effectiveness of the robust controllers under bounded power plant model uncertainties and exogenous wind input excitation while maximizing economical and ecological performance objectives. Therefore, the proposed framework offers a new worst-case deterministic

Improved Differential Evolution Algorithm for Wireless Sensor Network Coverage Optimization

Directory of Open Access Journals (Sweden)

Xing Xu

2014-04-01

Full Text Available In order to serve for the ecological monitoring efficiency of Poyang Lake, an improved hybrid algorithm, mixed with differential evolution and particle swarm optimization, is proposed and applied to optimize the coverage problem of wireless sensor network. And then, the affect of the population size and the number of iterations on the coverage performance are both discussed and analyzed. The four kinds of statistical results about the coverage rate are obtained through lots of simulation experiments.

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

Science.gov (United States)

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.

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