Science.gov

Sample records for wind-turbine-generator site summarized

  1. Candidate wind-turbine-generator site summarized meteorological data for December 1976-December 1981. [Program WIND listed

    SciTech Connect

    Sandusky, W.F.; Renne, D.S.; Hadley, D.L.

    1982-09-01

    Summarized hourly meteorological data for 16 of the original 17 candidate and wind turbine generator sites collected during the period from December 1976 through December 1981 are presented. The data collection program at some individual sites may not span this entire period, but will be contained within the reporting period. The purpose of providing the summarized data is to document the data collection program and provide data that could be considered representative of long-term meteorological conditions at each site. For each site, data are given in eight tables and a topographic map showing the location of the meteorological tower and turbine, if applicable. Use of information from these tables, along with information about specific wind turbines, should allow the user to estimate the potential for long-term average wind energy production at each site.

  2. Site-optimization of wind turbine generators

    SciTech Connect

    Wolff, T.J. de; Thillerup, J.

    1997-12-31

    The Danish Company Nordtank is one of the pioneers within the wind turbine industry. Since 1981 Nordtank has installed worldwide more than 2500 wind turbine generators with a total name plate capacity that is exceeding 450 MW. The opening up of new and widely divergent markets has demanded an extremely flexible approach towards wind turbine construction. The Nordtank product range has expanded considerable in recent years, with the main objective to develop wind energy conversion machines that can run profitable in any given case. This paper will describe site optimization of Nordtank wind turbines. Nordtank has developed a flexible design concept for its WTGs in the 500/750 kW range, in order to offer the optimal WTG solution for any given site and wind regime. Through this flexible design, the 500/750 turbine line can adjust the rotor diameter, tower height and many other components to optimally fit the turbine to each specific project. This design philosophy will be illustrated with some case histories of recently completed projects.

  3. Candidate wind turbine generator site: annual data summary, January 1981-December 1981

    SciTech Connect

    Sandusky, W.F.; Buck, J.W.; Renne, D.S.; Hadley, D.L.; Abbey, O.B.

    1982-07-01

    Summarized hourly meteorological data for 34 candidate and wind turbine generator sites for calendar year 1981 are presented. These data are collected for the purpose of evaluating the wind energy potential at these sites and are used to assist in selection of potential sites for installation and testing of large wind turbines in electric utility systems. For each site, wind speed, direction, and distribution data are given in eight tables. Use of information from these tables, with information about specific wind turbines, should allow the user to estimate the potential for wind energy production at each site.

  4. Candidate wind turbine generator site annual data summary for January 1979 through December 1979

    SciTech Connect

    Sandusky, W.F.; Renne, D.S.

    1981-03-01

    Summarized hourly meteorological data for fifteen candidate and wind turbine generator sites are presented in this report. These data are collected for the Department of Energy for the purpose of evaluating the wind energy potential at these sites and are used to assist in selection of potential sites for installation and testing of large wind turbines in electric utility systems. For each site, data are given in eight tables and one figure. Use of information from these tables, with information about specific wind turbines, should allow the user to estimate the potential for wind energy production at each site.

  5. Wake Studies at the Flowind Vertical Axis Wind Turbine Generator Site.

    SciTech Connect

    Baker, Robert W.; Walker, Stel Nathan; Katen, Paul C.

    1984-03-01

    In a continuing effort to study and characterize various types and sizes of wind turbine generator wakes a test program was conducted at the FloWind 170 kW vertical axis wind turbine (VAWT) near Ellensburg, Washington. Oregon State University (OSU) scientists measured the wake behind the 90 ft. tall Darrieus VAWT using fixed place and portable kite anemometers. Downwind velocity deficits were measured from 3-9 diameters along the wake centerline at rotor midpoint (55 ft.) and perpendicular to the wake. Wake turbulence characteristics were also measured. The measured velocity deficits were compared to wake model calculations.

  6. Wind turbine generator system

    SciTech Connect

    Kirschbaum, H.S.

    1982-11-02

    Wind turbine generator systems incorporating a multi-speed pole amplitude modulated type dynamo electric machine allow efficient operation at consecutive speeds in a ratio preferably less than 2:1. A current limiting reactor, preferably including an inductance coil, and an over-running clutch, are utilized in conjunction with any multi-speed generation system to alleviate impact on a utility grid during switching among operational speeds.

  7. Feasibility Study of Economics and Performance of Wind Turbine Generators at the Newport Indiana Chemical Depot Site

    SciTech Connect

    Roberts, Joseph Owen; Mosey, Gail

    2013-11-01

    The U.S. Environmental Protection Agency (EPA), in accordance with the RE-Powering America's Land initiative, selected the Newport Indiana Chemical Depot site in Newport, Indiana, for a feasibility study of renewable energy production. The National Renewable Energy Laboratory (NREL) was contacted to provide technical assistance for this project. The purpose of this report is to assess the sitefor possible wind turbine electrical generator installation and estimate the cost, performance, and site impacts of different wind energy options. In addition, the report recommends financing options that could assist in the implementation of a wind system at the site.

  8. Effect of wind turbine generator model and siting on wind power changes out of large WECS arrays

    NASA Technical Reports Server (NTRS)

    Schleuter, R. A.; Park, G. L.; Lotfalian, M.; Dorsey, J.; Shayanfar, H.

    1981-01-01

    Methods of reducing the WECS generation change through selection of the wind turbine model for each site, selection of an appropriate siting configuration, and wind array controls are discussed. An analysis of wind generation change from an echelon and a farm for passage of a thunderstorm is presented. Reduction of the wind generation change over ten minutes is shown to reduce the increase in spinning reserve, unloadable generation and load following requirements on unit commitment when significant WECS generation is present and the farm penetration constraint is satisfied. Controls on the blade pitch angle of all wind turbines in an array or a battery control are shown to reduce both the wind generation change out of an array and the effective farm penetration in anticipation of a storm so that the farm penetration constraint may be satisfied.

  9. Microprocessor control of a wind turbine generator

    NASA Technical Reports Server (NTRS)

    Gnecco, A. J.; Whitehead, G. T.

    1978-01-01

    A microprocessor based system was used to control the unattended operation of a wind turbine generator. The turbine and its microcomputer system are fully described with special emphasis on the wide variety of tasks performed by the microprocessor for the safe and efficient operation of the turbine. The flexibility, cost and reliability of the microprocessor were major factors in its selection.

  10. Mod-1 Wind Turbine Generator Analysis

    NASA Technical Reports Server (NTRS)

    Barton, R. S.

    1978-01-01

    A general summary of the MOD-1 wind turbine generator control system and simulation is presented. Mechanical and speed stabilization control means to add drive train damping were mentioned and MOD-1 simulation results showing the effects of speed stabilization are displayed.

  11. Mod-5A wind turbine generator program design report. Volume 3: Final design and system description, book 2

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The design, development and analysis of the 7.3MW MOD-5A wind turbine generator is documented. The report is divided into four volumes: Volume 1 summarizes the entire MOD-5A program, Volume 2 discusses the conceptual and preliminary design phases, Volume 3 describes the final design of the MOD-5A, and Volume 4 contains the drawings and specifications developed for the final design. Volume 3, book 2 describes the performance and characteristics of the MOD-5A wind turbine generator in its final configuration. The subsystem for power generation, control, and instrumentation subsystems is described in detail. The manufacturing and construction plans, and the preparation of a potential site on Oahu, Hawaii, are documented. The quality assurance and safety plan, and analyses of failure modes and effects, and reliability, availability and maintainability are presented.

  12. Model 0A wind turbine generator FMEA

    NASA Technical Reports Server (NTRS)

    Klein, William E.; Lalli, Vincent R.

    1989-01-01

    The results of Failure Modes and Effects Analysis (FMEA) conducted for the Wind Turbine Generators are presented. The FMEA was performed for the functional modes of each system, subsystem, or component. The single-point failures were eliminated for most of the systems. The blade system was the only exception. The qualitative probability of a blade separating was estimated at level D-remote. Many changes were made to the hardware as a result of this analysis. The most significant change was the addition of the safety system. Operational experience and need to improve machine availability have resulted in subsequent changes to the various systems which are also reflected in this FMEA.

  13. Broad band sound from wind turbine generators

    NASA Technical Reports Server (NTRS)

    Hubbard, H. H.; Shepherd, K. P.; Grosveld, F. W.

    1981-01-01

    Brief descriptions are given of the various types of large wind turbines and their sound characteristics. Candidate sources of broadband sound are identified and are rank ordered for a large upwind configuration wind turbine generator for which data are available. The rotor is noted to be the main source of broadband sound which arises from inflow turbulence and from the interactions of the turbulent boundary layer on the blade with its trailing edge. Sound is radiated about equally in all directions but the refraction effects of the wind produce an elongated contour pattern in the downwind direction.

  14. Wind turbine generator interaction with conventional diesel generators on Block Island, Rhode Island. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Wilreker, V. F.; Stiller, P. H.; Scott, G. W.; Kruse, V. J.; Smith, R. F.

    1984-01-01

    Primary results are summarized for a three-part study involving the effects of connecting a MOD-OA wind turbine generator to an isolated diesel power system. The MOD-OA installation considered was the third of four experimental nominal 200 kW wind turbines connected to various utilities under the Federal Wind Energy Program and was characterized by the highest wind energy penetration levels of four sites. The study analyses address: fuel displacement, dynamic interaction, and three modes of reactive power control. These analyses all have as their basis the results of the data acquisition program conducted on Block Island, Rhode Island.

  15. Wind Turbine Generator System Safety and Function Test Report for the Entegrity EW50 Wind Turbine

    SciTech Connect

    Smith, J.; Huskey, A.; Jager, D.; Hur, J.

    2012-11-01

    This report summarizes the results of a safety and function test that NREL conducted on the Entegrity EW50 wind turbine. This test was conducted in accordance with the International Electrotechnical Commissions' (IEC) standard, Wind Turbine Generator System Part 2: Design requirements for small wind turbines, IEC 61400-2 Ed.2.0, 2006-03.

  16. Wind Turbine Generator System Safety and Function Test Report for the Ventera VT10 Wind Turbine

    SciTech Connect

    Smith, J.; Huskey, A.; Jager, D.; Hur, J.

    2012-11-01

    This report summarizes the results of a safety and function test that NREL conducted on the Ventera VT10 wind turbine. This test was conducted in accordance with the International Electrotechnical Commissions' (IEC) standard, Wind Turbine Generator System Part 2: Design requirements for small wind turbines, IEC 61400-2 Ed.2.0, 2006-03.

  17. Mod-5A wind turbine generator program design report. Volume 4: Drawings and specifications, book 2

    NASA Astrophysics Data System (ADS)

    1984-08-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. There are four volumes. This volume contains the drawings and specifications that were developed in preparation for building the MOD-5A wind turbine generator. This is the second book of volume four. Some of the items it contains are specs for the emergency shutdown panel, specs for the simulator software, simulator hardware specs, site operator terminal requirements, control data system requirements, software project management plan, elastomeric teeter bearing requirement specs, specs for the controls electronic cabinet, and specs for bolt pretensioning.

  18. Mod-5A wind turbine generator program design report. Volume 4: Drawings and specifications, book 2

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. There are four volumes. This volume contains the drawings and specifications that were developed in preparation for building the MOD-5A wind turbine generator. This is the second book of volume four. Some of the items it contains are specs for the emergency shutdown panel, specs for the simulator software, simulator hardware specs, site operator terminal requirements, control data system requirements, software project management plan, elastomeric teeter bearing requirement specs, specs for the controls electronic cabinet, and specs for bolt pretensioning.

  19. Measurements and observations of noise from a 4.2 megawatt (WTS-4) wind turbine generator

    NASA Technical Reports Server (NTRS)

    Shepherd, K. P.; Hubbard, H. H.

    1983-01-01

    Noise measurements and calculations are being made for large wind turbine generators to develop a data base for use in designing and siting such systems for community acceptance. As part of this program, measurements were made on the WTS-4 wind turbine generator during its acceptance runs. This paper presents the results of these exploratory measurements for power output conditions in the range 1.0 to 4.2 MW. Data include noise levels, spectra, radiation patterns, effects of distance, and the associated perception thresholds for use in the further development of acceptance criteria for this type of machine.

  20. Utility experience with two demonstration wind turbine generators

    NASA Technical Reports Server (NTRS)

    Wehrey, M. C.

    1982-01-01

    Edison has committed 360 MW of nameplate generating capacity to wind energy by year 1990 in its long-range generation plan. To reach this goal the Company's wind energy program focuses on three areas: the continuous evaluation of the wind resource, the hands-on demonstration of wind turbine generators (WTG) and an association with wind park developers. Two demonstration WTGs have been installed and operated at Edison's Wind Energy Center near Palm Springs, California: a 3 MW horizontal axis Bendix/Schachle WTG and a 500 kW vertical axis Alcoa WTG. They are part of a one to two year test program during which the performance of the WTGs will be evaluated, their system operation and environmental impact will be assessed and the design criteria of future WTGs will be identified. Edison's experience with these two WTGs is summarized and the problems encountered with the operation of the two machines are discussed.

  1. Condition monitoring system of wind turbine generators

    NASA Astrophysics Data System (ADS)

    Abdusamad, Khaled B.

    The development and implementation of the condition monitoring systems (CMS) play a significant role in overcoming the number of failures in the wind turbine generators that result from the harsh operation conditions, such as over temperature, particularly when turbines are deployed offshore. In order to increase the reliability of the wind energy industry, monitoring the operation conditions of wind generators is essential to detect the immediate faults rapidly and perform appropriate preventative maintenance. CMS helps to avoid failures, decrease the potential shutdowns while running, reduce the maintenance and operation costs and maintain wind turbines protected. The knowledge of wind turbine generators' faults, such as stator and rotor inter-turn faults, is indispensable to perform the condition monitoring accurately, and assist with maintenance decision making. Many techniques are utilized to avoid the occurrence of failures in wind turbine generators. The majority of the previous techniques that are applied to monitor the wind generator conditions are based on electrical and mechanical concepts and theories. An advanced CMS can be implemented by using a variety of different techniques and methods to confirm the validity of the obtained electrical and mechanical condition monitoring algorithms. This thesis is focused on applying CMS on wind generators due to high temperature by contributing the statistical, thermal, mathematical, and reliability analyses, and mechanical concepts with the electrical methodology, instead of analyzing the electrical signal and frequencies trends only. The newly developed algorithms can be compared with previous condition monitoring methods, which use the electrical approach in order to establish their advantages and limitations. For example, the hazard reliability techniques of wind generators based on CMS are applied to develop a proper maintenance strategy, which aims to extend the system life-time and reduce the potential

  2. The General Electric MOD-1 wind turbine generator program

    NASA Technical Reports Server (NTRS)

    Poor, R. H.; Hobbs, R. B.

    1979-01-01

    The design, fabrication, installation and checkout of MOD-1, a megawatt class wind turbine generator which generates utility grade electrical power, is described. A MOD-1/MOD-1A tradeoff study is discussed.

  3. Variable speed generator technology options for wind turbine generators

    NASA Technical Reports Server (NTRS)

    Lipo, T. A.

    1995-01-01

    The electrical system options for variable speed operation of a wind turbine generator are treated in this paper. The key operating characteristics of each system are discussed and the major advantages and disadvantages of each are identified

  4. Dual-speed wind turbine generation

    SciTech Connect

    Muljadi, E.; Butterfield, C.P.; Handman, D.

    1996-10-01

    Induction generator has been used since the early development of utility-scale wind turbine generation. An induction generator is the generator of choice because of its ruggedness and low cost. With an induction generator, the operating speed of the wind turbine is limited to a narrow range (almost constant speed). Dual- speed operation can be accomplished by using an induction generator with two different sets of winding configurations or by using a dual output drive train to drive two induction generators with two different rated speeds. With single-speed operation, the wind turbine operates at different power coefficients (Cp) as the wind speed varies. Operation at maximum Cp can occur only at a single wind speed. However, if the wind speed.varies across a wider range, the operating Cp will vary significantly. Dual-speed operation has the advantage of enabling the wind turbine to operate at near maximum Cp over a wider range of wind speeds. Thus, annual energy production can be increased. The dual-speed mode may generate less energy than a variable-speed mode; nevertheless, it offers an alternative which captures more energy than single-speed operation. In this paper, dual-speed operation of a wind turbine is investigated. Annual energy production is compared between single-speed and dual-speed operation. One type of control algorithm for dual-speed operation is proposed. Some results from a dynamic simulation will be presented to show how the control algorithm works as the wind turbine is exposed to varying wind speeds.

  5. Development tests for the 2.5 megawatt Mod-2 wind turbine generator

    NASA Technical Reports Server (NTRS)

    Andrews, J. S.; Baskin, J. M.

    1982-01-01

    The 2.5 megawatt MOD-2 wind turbine generator test program is discussed. The development of the 2.5 megawatt MOD-2 wind turbine generator included an extensive program of testing which encompassed verification of analytical procedures, component development, and integrated system verification. The test program was to assure achievement of the thirty year design operational life of the wind turbine system as well as to minimize costly design modifications which would otherwise have been required during on site system testing. Computer codes were modified, fatigue life of structure and dynamic components were verified, mechanical and electrical component and subsystems were functionally checked and modified where necessary to meet system specifications, and measured dynamic responses of coupled systems confirmed analytical predictions.

  6. Investigation of excitation control for wind-turbine generator stability

    NASA Technical Reports Server (NTRS)

    Gebben, V. D.

    1977-01-01

    High speed horizontal axis wind turbine generators with blades on the downwind side of the support tower require special design considerations to handle disturbances introduced by the flow wake behind the tower. Experiments and analytical analyses were made to determine benefits that might be obtained by using the generator exciter to provide system damping for reducing power fluctuations.

  7. Wind Turbine Generator System Power Performance Test Report for the ARE442 Wind Turbine

    SciTech Connect

    van Dam, J.; Jager, D.

    2010-02-01

    This report summarizes the results of a power performance test that NREL conducted on the ARE 442 wind turbine. This test was conducted in accordance with the International Electrotechnical Commission's (IEC) standard, Wind Turbine Generator Systems Part 12: Power Performance Measurements of Electricity Producing Wind Turbines, IEC 61400-12-1 Ed.1.0, 2005-12. However, because the ARE 442 is a small turbine as defined by IEC, NREL also followed Annex H that applies to small wind turbines. In these summary results, wind speed is normalized to sea-level air density.

  8. ERCOT's Dynamic Model of Wind Turbine Generators: Preprint

    SciTech Connect

    Muljadi, E.; Butterfield, C. P.; Conto, J.; Donoho, K.

    2005-08-01

    By the end of 2003, the total installed wind farm capacity in the Electric Reliability Council of Texas (ERCOT) system was approximately 1 gigawatt (GW) and the total in the United States was about 5 GW. As the number of wind turbines installed throughout the United States increases, there is a greater need for dynamic wind turbine generator models that can properly model entire power systems for different types of analysis. This paper describes the ERCOT dynamic models and simulations of a simple network with different types of wind turbine models currently available.

  9. Methods and apparatus for cooling wind turbine generators

    DOEpatents

    Salamah, Samir A.; Gadre, Aniruddha Dattatraya; Garg, Jivtesh; Bagepalli, Bharat Sampathkumaran; Jansen, Patrick Lee; Carl, Jr., Ralph James

    2008-10-28

    A wind turbine generator includes a stator having a core and a plurality of stator windings circumferentially spaced about a generator longitudinal axis. A rotor is rotatable about the generator longitudinal axis, and the rotor includes a plurality of magnetic elements coupled to the rotor and cooperating with the stator windings. The magnetic elements are configured to generate a magnetic field and the stator windings are configured to interact with the magnetic field to generate a voltage in the stator windings. A heat pipe assembly thermally engaging one of the stator and the rotor to dissipate heat generated in the stator or rotor.

  10. Control of large wind turbine generators connected to utility networks

    NASA Technical Reports Server (NTRS)

    Hinrichsen, E. N.

    1983-01-01

    This is an investigation of the control requirements for variable pitch wind turbine generators connected to electric power systems. The requirements include operation in very small as well as very large power systems. Control systems are developed for wind turbines with synchronous, induction, and doubly fed generators. Simulation results are presented. It is shown how wind turbines and power system controls can be integrated. A clear distinction is made between fast control of turbine torque, which is a peculiarity of wind turbines, and slow control of electric power, which is a traditional power system requirement.

  11. The 100 kW experimental wind turbine generator project

    NASA Technical Reports Server (NTRS)

    Puthoff, R. L.; Sirocky, P.

    1975-01-01

    The Energy Research and Development Administration and the NASA Lewis Research Center engaged jointly in a Wind Energy Program which included the design and erection of a 100 kW wind turbine generator. This test machine consists of a rotor turbine, transmission, shaft, alternator, and tower. The rotor, measuring 125 feet in diameter and consisting of two variable pitch blades, operates at 40 rpm and generates 100 kW of electrical power at a wind velocity of 18 mph. The entire assembly is placed on top of a tower 100 feet above ground level. The machine was scheduled to be ready for operation in August, 1975.

  12. Calculation of guaranteed mean power from wind turbine generators

    NASA Technical Reports Server (NTRS)

    Spera, D. A.

    1981-01-01

    A method for calculating the 'guaranteed mean' power output of a wind turbine generator is proposed. The term 'mean power' refers to the average power generated at specified wind speeds during short-term tests. Correlation of anemometers, the method of bins for analyzing non-steady data, the PROP Code for predicting turbine power, and statistical analysis of deviations in test data from theory are discussed. Guaranteed mean power density for the Clayton Mod-OA system was found to be 8 watts per square meter less than theoretical power density at all power levels, with a confidence level of 0.999. This amounts to 4 percent of rated power.

  13. Power fluctuations smoothing and regulations in wind turbine generator systems

    NASA Astrophysics Data System (ADS)

    Babazadehrokni, Hamed

    Wind is one of the most popular renewable energy sources and it has the potential to become the biggest energy source in future. Since the wind does not always blow constantly, the output wind power is not constant which may make some problem for the power grid. According to the grid code which is set by independent system operator, ISO, wind turbine generator systems need to follow some standards such as the predetermined acceptable power fluctuations. In order to smooth the output powers, the energy storage system and some power electronics modules are employed. The utilized power electronics modules in the wind turbine system can pursue many different goals, such as maintaining the voltage stability, frequency stability, providing the available and predetermined output active and reactive power. On the other side, the energy storage system can help achieving some of these goals but its main job is to store the extra energy when not needed and release the stored energy when needed. The energy storage system can be designed in different sizes, material and also combination of different energy storage systems (hybrid designs). Combination of power electronics devises and also energy storage system helps the wind turbine systems to smooth the output power according to the provided standards. In addition prediction of wind speed may improve the performance of wind turbine generator systems. In this research study all these three topics are studied and the obtained results are written in 10 papers which 7 of them are published and three of them are under process.

  14. Mod-5A wind turbine generator program design report. Volume 4: Drawings and specifications, book 5

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. There are four volumes. This volume contains the drawings and specifications that were developed in preparation for building the MOD-5A wind turbine generator. Detail drawings of several assemblies and subassemblies are given. This is the fifth book of volume 4.

  15. Variable Speed Wind Turbine Generator with Zero-sequence Filter

    DOEpatents

    Muljadi, Eduard

    1998-08-25

    A variable speed wind turbine generator system to convert mechanical power into electrical power or energy and to recover the electrical power or energy in the form of three phase alternating current and return the power or energy to a utility or other load with single phase sinusoidal waveform at sixty (60) hertz and unity power factor includes an excitation controller for generating three phase commanded current, a generator, and a zero sequence filter. Each commanded current signal includes two components: a positive sequence variable frequency current signal to provide the balanced three phase excitation currents required in the stator windings of the generator to generate the rotating magnetic field needed to recover an optimum level of real power from the generator; and a zero frequency sixty (60) hertz current signal to allow the real power generated by the generator to be supplied to the utility. The positive sequence current signals are balanced three phase signals and are prevented from entering the utility by the zero sequence filter. The zero sequence current signals have zero phase displacement from each other and are prevented from entering the generator by the star connected stator windings. The zero sequence filter allows the zero sequence current signals to pass through to deliver power to the utility.

  16. Stabilization of Wind Turbine Generator System by STATCOM

    NASA Astrophysics Data System (ADS)

    Muyeen, S. M.; Mannan, Mohammad Abdul; Ali, Mohd. Hasan; Takahashi, Rion; Murata, Toshiaki; Tamura, Junji

    Recently voltage-source or current-source inverter based various FACTS devices have been used for flexible power flow control, secure loading, damping of power system oscillation and even for the stabilization of wind energy generation. In this paper, we propose the static synchronous compensator (STATCOM) based on voltage source converter (VSC) PWM technique to stabilize grid connected wind generator system. A simple control strategy of STATCOM is adopted where only measurement of rms voltage at the wind generator terminal is needed. Fuzzy logic controller rather than conventional PI controller is proposed as the control methodology of STATCOM. Multi-mass shaft model of wind turbine generator system (WTGS) is also considered as shaft modeling has a big influence on the transient performance of WTGS. Transient performance of STATCOM connected WTGS is compared also with that of pitch controlled WTGS. Both symmetrical and unsymmetrical faults are analyzed. Moreover, the steady state performance of STATCOM connected WTGS is analyzed. It is reported that STATCOM can reduce the voltage fluctuation significantly. Finally STATCOM is applied to a wind park model with multiple wind generators. Comprehensive results are presented to assess the performance of STATCOM connected WTGS, where the simulations have been done by PSCAD/EMTDC.

  17. Sound measurements of the MOD-2 wind turbine generator

    NASA Technical Reports Server (NTRS)

    Hubbard, H. H.; Shepherd, K. P.; Grosveld, F. W.

    1981-01-01

    Sound measurements were made for the MOD-2 wind turbine generator for wind conditions of 7.6 to 13.4 m/sec and for output power ratings of about 1 to 2 NW. Both broad band and narrow band data wre obtained for a range of distances and azimuth angles from the machine. The rotor sound spectra are random in character and peak in the frequency ranges 30 to 50 Hz and 800 to 1300 Hz. Both peaks are predictable from experience with helicopter rotors and propellers. Results suggest that the lower frequency peak is due to the effects of inflow turbulence and the higher frequency peak is due to the interactions of the turbulent boundary layers with the trailing edges of the blades. The boundary layer related sound is the dominant component in the audible frequency range and determines the detectability of the machine. It could be detected at a distance of 1350 m in the upwind direction where the background noise was 30 dB (A) and at distances in excess of 2100 m in the downwind direction. Discrete frequency sound components associated with the power generation equipment are measurable in the direction normal to the axis of rotation but are not believed to be significant for detection or community response.

  18. Short Circuit Current Contribution for Different Wind Turbine Generator Types

    SciTech Connect

    Muljadi, E.; Samaan, Nader A.; Gevorgian, Vahan; Li, Jun; Pasupulati, Subbaiah

    2010-09-28

    An important aspect of wind power plant (WPP) impact studies is to evaluate the short circuit (SC) current contribution of the plant into the transmission network under different fault conditions. This task can be challenging to protection engineers due to the topology differences between different types of wind turbine generators (WTGs) and the conventional generating units. This paper represents simulation results for short circuit current contribution for different types of WTGs obtained through transient analysis using generic WTG models. The obtained waveforms are analyzed to explain the behavior, such as peak values and rate of decay, of the WTG. The effect of fault types and location, and the effect of the control algorithms of power converters on SC current contribution are investigated. It is shown that the response of the WPP to faults will vary based on the type of the installed WTGs. While in Type 1 and Type 2 WTGs, short circuit current will be determined by the physical characteristics of the induction generator, the contribu-tion of Type 3 and Type 4 WTG will be mostly characterized by the power converters control algorithms which are usually considered proprietary information by the wind turbine manufacturers.

  19. Dynamic simulation of dual-speed wind turbine generation

    SciTech Connect

    Muljadi, E.; Butterfield, C.P.

    1996-10-01

    Induction generators have been used since the early development of utility-scale wind turbine generation. An induction generator is the generator of choice because of its ruggedness, and low cost. With an induction generator, the operating speed of the wind turbine is limited to a narrow range (almost constant speed). Dual- speed operation can be accomplished by using an induction generator with two different sets of winding configurations or by using two induction generators with two different rated speeds. With single- speed operation, the wind turbine operates at different power coefficients (Cp) as the wind speed varies. The operation at maximum Cp can occur only at a single wind speed. However, if the wind speed varies across a wider range, the operating Cp will vary significantly. Dual-speed operation has the advantage of enabling the wind turbine to operate at near maximum Cp over a wider range of wind-speeds. Thus, annual energy production can be increased. The dual-speed mode may generate less energy than a variable-speed mode; nevertheless, it offers an alternative to capture more energy than single-speed operation. In this paper, dual-speed operation of a wind turbine will be investigated. One type of control algorithm for dual- speed operation is proposed. Results from a dynamic simulation will be presented to show how the control algorithm works and how power, current and torque of the system vary as the wind turbine is exposed to varying wind speeds.

  20. Variable speed wind turbine generator with zero-sequence filter

    DOEpatents

    Muljadi, E.

    1998-08-25

    A variable speed wind turbine generator system to convert mechanical power into electrical power or energy and to recover the electrical power or energy in the form of three phase alternating current and return the power or energy to a utility or other load with single phase sinusoidal waveform at sixty (60) hertz and unity power factor includes an excitation controller for generating three phase commanded current, a generator, and a zero sequence filter. Each commanded current signal includes two components: a positive sequence variable frequency current signal to provide the balanced three phase excitation currents required in the stator windings of the generator to generate the rotating magnetic field needed to recover an optimum level of real power from the generator; and a zero frequency sixty (60) hertz current signal to allow the real power generated by the generator to be supplied to the utility. The positive sequence current signals are balanced three phase signals and are prevented from entering the utility by the zero sequence filter. The zero sequence current signals have zero phase displacement from each other and are prevented from entering the generator by the star connected stator windings. The zero sequence filter allows the zero sequence current signals to pass through to deliver power to the utility. 14 figs.

  1. Variable speed wind turbine generator with zero-sequence filter

    DOEpatents

    Muljadi, Eduard

    1998-01-01

    A variable speed wind turbine generator system to convert mechanical power into electrical power or energy and to recover the electrical power or energy in the form of three phase alternating current and return the power or energy to a utility or other load with single phase sinusoidal waveform at sixty (60) hertz and unity power factor includes an excitation controller for generating three phase commanded current, a generator, and a zero sequence filter. Each commanded current signal includes two components: a positive sequence variable frequency current signal to provide the balanced three phase excitation currents required in the stator windings of the generator to generate the rotating magnetic field needed to recover an optimum level of real power from the generator; and a zero frequency sixty (60) hertz current signal to allow the real power generated by the generator to be supplied to the utility. The positive sequence current signals are balanced three phase signals and are prevented from entering the utility by the zero sequence filter. The zero sequence current signals have zero phase displacement from each other and are prevented from entering the generator by the star connected stator windings. The zero sequence filter allows the zero sequence current signals to pass through to deliver power to the utility.

  2. Control and stabilization of the DOE/NASA Mod-1 two megawatt wind turbine generator

    NASA Technical Reports Server (NTRS)

    Barton, R. S.; Bowler, C. E. J.; Piwko, R. J.

    1979-01-01

    This paper describes the controls design, performance simulation process and specialized dynamic considerations for the DOE/NASA Mod 1 wind turbine generator (WTG). It shows controls, structural and utility interface considerations of the wind turbine generator and shows how a wind turbine generator can be integrated with a synchronous power system. Differences with respect to fossil or hydro generation and their implications are vital to long-term WTG reliability and availability and acceptance by utilities and consumers. The paper describes the control performance requirements to provide stable pitch and excitation control with drivetrain torsional dynamics, and the control of power swing stability and utility feeder voltage due to wind gusts.

  3. Operational experience on the MP-200 series commercial wind turbine generators

    NASA Technical Reports Server (NTRS)

    Rose, M. B.

    1982-01-01

    The MP-200 wind turbine generator is described. The mechanical system, microprocessor controller, and display devices, are described. Also discussed are modifications to the prototype, operational experience, and MP-600 systems development.

  4. MOD-5A wind turbine generator program design report: Volume 1: Executive Summary

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator covering work performed between July 1980 and June 1984 is discussed. The report is divided into four volumes: Volume 1 summarizes the entire MOD-5A program, Volume 2 discusses the conceptual and preliminary design phases, Volume 3 describes the final design of the MOD-5A, and Volume 4 contains the drawings and specifications developed for the final design. Volume 1, the Executive Summary, summarizes all phases of the MOD-5A program. The performance and cost of energy generated by the MOD-5A are presented. Each subsystem - the rotor, drivetrain, nacelle, tower and foundation, power generation, and control and instrumentation subsystems - is described briefly. The early phases of the MOD-5A program, during which the design was analyzed and optimized, and new technologies and materials were developed, are discussed. Manufacturing, quality assurance, and safety plans are presented. The volume concludes with an index of volumes 2 and 3.

  5. Development of Trouble Diagnosis Technology of 50W Grade Small Wind Turbine Generator

    NASA Astrophysics Data System (ADS)

    Takaoka, Masashige; Inohata, Kazuki; Miyake, Takuma; Tashima, Daisuke; Otsubo, Masahisa; Bouno, Toshio

    Establishment of an early trouble diagnosis system is demanded to prevent damage of wind turbine generator. Therefore, AE signal occurring by the damage of a wind blade was detected with the AE sensor which installed to the body of wind turbine generator and a pole. In this study, length of a blade of a small wind turbine generator was changed as simulated trouble in the constant wind velocity. The AE signal which occurred at this time was measured with an AE sensor. The signal was processed by FFT analysis, and a change of spectrum strength was examined. Then, trouble diagnosis technology of 50W grade small wind turbine generator was developed. As the results, a method to count the number of times more than threshold of AE signals was suggested by a wave pattern of an AE signal. It was understood that the number of the count was decided as standard to judge normality or abnormality of 50W grade small wind turbine generator.

  6. National Renewable Energy Laboratory program on lightning risk and wind turbine generator protection

    SciTech Connect

    Muljadi, E.; McNiff, B.

    1997-12-31

    In the early development of wind turbine generators (WTG) in the United States, wind farms were primarily located in California where lightning activity is the lowest in the United States. As such, lightning protection for wind turbines was not considered to be a major issue for designers or wind farm operators. However, wind turbine installations are expanding into the Midwest, Southwest and other regions of the United States where lightning activity is significantly more intense and lightning damage to wind turbines is more common. There is a growing need, therefore, to better understand lightning activity on wind farms and to improve wind turbine lightning protection systems. In support of the U.S. Department of Energy/Electric Power Research Institute (DOE/EPRI) Utility Wind Turbine Verification Program (TVP), the National Renewable Energy Laboratory (NREL) has recently begun to take steps to determine the extent of damage due to lightning and the effectiveness of various lightning protection techniques for wind power plants. Working through the TVP program, NREL will also perform outreach and education to (1) help manufacturers to provide equipment that is adequately designed to survive lightning, (2) make sure that operators are aware of effective safety procedures, and (3) help site designers and wind farm developers take the risk of lightning into account as effectively as possible.

  7. Mod-5A wind turbine generator program design report. Volume 4: Drawings and specifications, book 4

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator are documented. There are four volumes. This volume contains the drawings and specifications that were developed in preparation for building the MOD-5A wind turbine generator. This volume contains 5 books of which this is the fourth, providing drawings 47A380128 through 47A387125. In addition to the parts listing and where-used list, the logic design of the controller software and the code listing of the controller software are provided. Also given are the aerodynamic profile coordinates.

  8. Mod-5A Wind Turbine Generator Program Design Report. Volume 4: Drawings and Specifications, Book 1

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. Volume 4 contains the drawings and specifications that were developed in preparation for building the MOD-5A wind turbine generator. This is the first of five books of volume four. It contains structural design criteria, generator step-up transformer specs, specs for design, fabrication and testing of the system, specs for the ground control enclosure, systems specs, slip ring specs, and control system specs.

  9. Representation of Type 4 wind turbine generator for steady state short-circuit calculations

    NASA Astrophysics Data System (ADS)

    Kamara, Wouleye

    Various technical impacts are associated to the interconnection of wind turbine generators to the grid. Among them, the increase of short-circuit levels along with its effect on the settings of protecting relays has long acted as an important inhibiting factor for the interconnection of new wind power plants to the grid. This is especially true at the medium voltage level where networks operate close to their short-circuit design value [1]. As renewable energies are progressively replacing traditional power generation sources, short-circuit studies need to adequately assess the impact of newly interconnected wind power plants on the fault level of the network. For planning and design purposes, short-circuit studies are usually performed using steady-state short-circuit programs. Unfortunately, very few have developed models of wind turbine generators that accurately estimate their fault contribution in the phase domain. In particular, no commercial fault-flow analysis program specifically addresses the modeling of inverter-based wind turbine generators which behavior is based on the inverter's characteristics rather than the generator's. The main contribution of this research work is the development of a simplified and yet accurate model of full-scale converter based wind turbine generator, also called Type 4 wind turbine generator, for steady-state short-circuit calculations. The model reproduces the real behavior of the Type 4 wind turbine generator under fault conditions by correctly accounting for the effect of the full-scale converter. The data used for the model is easily accessible to planning engineers. An additional contribution of this research work is the development of a short-circuit algorithm adapted to support the proposed model of Type 4 wind-turbine generator. Short-circuit algorithm based on modified-augmented-nodal analysis (MANA) is solved iteratively to accommodate the proposed model. The algorithm is successfully implemented in CYME 7.0, a

  10. Mod-5A wind turbine generator program design report. Volume 3: Final design and system description, book 1

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. Volume 3, book 1 describes the performance and characteristics of the MOD-5A wind turbine generator in its final configuration. Each subsystem - the rotor, drivetrain, nacelle, tower and foundation is described in detail.

  11. Executive summary: Mod-1 wind turbine generator analysis and design report

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Activities leading to the detail design of a wind turbine generator having a nominal rating of 1.8 megawatts are reported. Topics covered include (1) system description; (2) structural dynamics; (3) stability analysis; (4) mechanical subassemblies design; (5) power generation subsystem; and (6) control and instrumentation subsystem.

  12. Synchronization of the DOE/NASA 100-kilowatt wind turbine generator with a large utility network

    NASA Technical Reports Server (NTRS)

    Gilbert, L. J.

    1977-01-01

    The DOE/NASA 100 kilowatt wind turbine generator system was synchronized with a large utility network. The system equipments and procedures associated with the synchronization process were described. Time history traces of typical synchronizations were presented indicating that power and current transients resulting from the synchronizing procedure are limited to acceptable magnitudes.

  13. MOD-1 Wind Turbine Generator Analysis and Design Report, Volume 2

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The MOD-1 detail design is appended. The supporting analyses presented include a parametric system trade study, a verification of the computer codes used for rotor loads analysis, a metal blade study, and a definition of the design loads at each principal wind turbine generator interface for critical loading conditions. Shipping and assembly requirements, composite blade development, and electrical stability are also discussed.

  14. Status of the Southern California Edison Company 3 MW Wind Turbine Generator (WTG) demonstration project

    NASA Technical Reports Server (NTRS)

    Scheffler, R. L.

    1979-01-01

    To demonstrate the concept of utility scale electricity production from a high wind energy resource, a program was initiated to construct and test a 3 megawatt (3,000 kW) Schachle wind turbine generator near Palm Springs, California. The background and current status of this program are presented along with a summary of future planned program activities.

  15. Mod-1 wind turbine generator analysis and design report, volume 1

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The activities leading to the completion of detail design of the MOD-1 wind turbine generator are described. Emphasis is placed on the description of the design as it finally evolved. However, the steps through which the design progressed are also traced in order to understand the major design decisions.

  16. Variable speed generator application on the MOD-5A 7.3 mW wind turbine generator

    NASA Astrophysics Data System (ADS)

    Barton, Robert S.

    1995-05-01

    This paper describes the application of a Scherbiustat type variable speed subsystem in the MOD-5A Wind Turbine Generator. As designed by General Electric Company, Advanced Energy Programs Department, under contract DEN3-153 with NASA Lewis Research Center and DOE, the MOD-5A utilizes the subsystem for both starting assistance in a motoring mode and generation in a controlled airgap torque mode. Reactive power control is also provided. The Scherbiustat type arrangement of a wound rotor machine with a cycloconverter in the rotor circuit was selected after an evaluation of variable speed technologies that followed a system evaluation of drivetrain cost and risk. The paper describes the evaluation factors considered, the results of the evaluations and summarizes operating strategy and performance simulations.

  17. Variable speed generator application on the MOD-5A 7.3 mW wind turbine generator

    NASA Technical Reports Server (NTRS)

    Barton, Robert S.

    1995-01-01

    This paper describes the application of a Scherbiustat type variable speed subsystem in the MOD-5A Wind Turbine Generator. As designed by General Electric Company, Advanced Energy Programs Department, under contract DEN3-153 with NASA Lewis Research Center and DOE, the MOD-5A utilizes the subsystem for both starting assistance in a motoring mode and generation in a controlled airgap torque mode. Reactive power control is also provided. The Scherbiustat type arrangement of a wound rotor machine with a cycloconverter in the rotor circuit was selected after an evaluation of variable speed technologies that followed a system evaluation of drivetrain cost and risk. The paper describes the evaluation factors considered, the results of the evaluations and summarizes operating strategy and performance simulations.

  18. Preliminary analysis of performance and loads data from the 2-megawatt mod-1 wind turbine generator

    NASA Technical Reports Server (NTRS)

    Spera, D. A.; Viterna, L. A.; Richards, T. R.; Neustadter, H. E.

    1979-01-01

    Preliminary test data on output power versus wind speed, rotor blade loads, system dynamic behavior, and start-stop characteristics on the Mod-1 wind turbine generator are presented. These data were analyzed statistically and are compared with design predictions of system performance and loads. To date, the Mod-1 wind turbine generator has produced up to 1.5 MW of power, with a measured power versus wind speed curve which agrees closely with design. Blade loads were measured at wind speeds up to 14 m/s and also during rapid shutdowns. Peak transient loads during the most severe shutdowns are less than the design limit loads. On the inboard blade sections, fatigue loads are approximately equal to the design cyclic loads. On the outboard blade sections, however, measured cyclic loads are significantly larger than design values, but they do not appear to exceed fatigue allowable loads as yet.

  19. Lewis Research Center studies of multiple large wind turbine generators on a utility network

    NASA Technical Reports Server (NTRS)

    Gilbert, L. J.; Triezenberg, D. M.

    1979-01-01

    A NASA-Lewis program to study the anticipated performance of a wind turbine generator farm on an electric utility network is surveyed. The paper describes the approach of the Lewis Wind Energy Project Office to developing analysis capabilities in the area of wind turbine generator-utility network computer simulations. Attention is given to areas such as, the Lewis Purdue hybrid simulation, an independent stability study, DOE multiunit plant study, and the WEST simulator. Also covered are the Lewis mod-2 simulation including analog simulation of a two wind turbine system and comparison with Boeing simulation results, and gust response of a two machine model. Finally future work to be done is noted and it is concluded that the study shows little interaction between the generators and between the generators and the bus.

  20. Simulation studies of multiple large wind turbine generators on a utility network

    NASA Technical Reports Server (NTRS)

    Gilbert, L. J.; Triezenberg, D. M.

    1979-01-01

    The potential electrical problems that may be inherent in the inertia of clusters of wind turbine generators and an electric utility network were investigated. Preliminary and limited results of an analog simulation of two MOD-2 wind generators tied to an infinite bus indicate little interaction between the generators and between the generators and the bus. The system demonstrated transient stability for the conditions considered.

  1. Mod-5A wind turbine generator program design report. Volume 4: Drawings and specifications, book 3

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. This volume contains the drawings and specifications developed for the final design. This volume is divided into 5 books of which this is the third, containing drawings 47A380074 through 47A380126. A full breakdown parts listing is provided as well as a where used list.

  2. Comparison of measured and calculated sound pressure levels around a large horizontal axis wind turbine generator

    NASA Technical Reports Server (NTRS)

    Shepherd, Kevin P.; Willshire, William L., Jr.; Hubbard, Harvey H.

    1989-01-01

    Results are reported from a large number of simultaneous acoustic measurements around a large horizontal axis downwind configuration wind turbine generator. In addition, comparisons are made between measurements and calculations of both the discrete frequency rotational harmonics and the broad band noise components. Sound pressure time histories and noise radiation patterns as well as narrow band and broadband noise spectra are presented for a range of operating conditions. The data are useful for purposes of environmental impact assessment.

  3. Model-OA wind turbine generator - Failure modes and effects analysis

    NASA Technical Reports Server (NTRS)

    Klein, William E.; Lali, Vincent R.

    1990-01-01

    The results failure modes and effects analysis (FMEA) conducted for wind-turbine generators are presented. The FMEA was performed for the functional modes of each system, subsystem, or component. The single-point failures were eliminated for most of the systems. The blade system was the only exception. The qualitative probability of a blade separating was estimated at level D-remote. Many changes were made to the hardware as a result of this analysis. The most significant change was the addition of the safety system. Operational experience and need to improve machine availability have resulted in subsequent changes to the various systems, which are also reflected in this FMEA.

  4. Power train analysis for the DOE/NASA 100-kW wind turbine generator

    NASA Technical Reports Server (NTRS)

    Seidel, R. C.; Gold, H.; Wenzel, L. M.

    1978-01-01

    Progress in explaining variations of power experienced in the on-line operation of a 100 kW experimental wind turbine-generator is reported. Data are presented that show the oscillations tend to be characteristic of a wind-driven synchronous generator because of low torsional damping in the power train, resonances of its large structure, and excitation by unsteady and nonuniform wind flow. The report includes dynamic analysis of the drive-train torsion, the generator, passive driveline damping, and active pitch control as well as correlation with experimental recordings. The analysis assumes one machine on an infinite bus with constant generator-field excitation.

  5. Operational-Condition-Independent Criteria Dedicated to Monitoring Wind Turbine Generators: Preprint

    SciTech Connect

    Yang, W.; Sheng, S.; Court, R.

    2012-08-01

    To date the existing wind turbine condition monitoring technologies and commercially available systems have not been fully accepted for improving wind turbine availability and reducing their operation and maintenance costs. One of the main reasons is that wind turbines are subject to constantly varying loads and operate at variable rotational speeds. As a consequence, the influences of turbine faults and the effects of varying load and speed are coupled together in wind turbine condition monitoring signals. So, there is an urgent need to either introduce some operational condition de-coupling procedures into the current wind turbine condition monitoring techniques or develop a new operational condition independent wind turbine condition monitoring technique to maintain high turbine availability and achieve the expected economic benefits from wind. The purpose of this paper is to develop such a technique. In the paper, three operational condition independent criteria are developed dedicated for monitoring the operation and health condition of wind turbine generators. All proposed criteria have been tested through both simulated and practical experiments. The experiments have shown that these criteria provide a solution for detecting both mechanical and electrical faults occurring in wind turbine generators.

  6. Transient response to three-phase faults on a wind turbine generator. Ph.D. Thesis - Toledo Univ.

    NASA Technical Reports Server (NTRS)

    Gilbert, L. J.

    1978-01-01

    In order to obtain a measure of its responses to short circuits a large horizontal axis wind turbine generator was modeled and its performance was simulated on a digital computer. Simulation of short circuit faults on the synchronous alternator of a wind turbine generator, without resort to the classical assumptions generally made for that analysis, indicates that maximum clearing times for the system tied to an infinite bus are longer than the typical clearing times for equivalent capacity conventional machines. Also, maximum clearing times are independent of tower shadow and wind shear. Variation of circuit conditions produce the modifications in the transient response predicted by analysis.

  7. Mod-5A Wind Turbine Generator Program Design Report. Volume 2: Conceptual and Preliminary Design, Book 1

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. There are four volumes. In Volume 2, book 1 the requirements and criteria for the design are presented. The conceptual design studies, which defined a baseline configuration and determined the weights, costs and sizes of each subsystem, are described. The development and optimization of the wind turbine generator are presented through the description of the ten intermediate configurations between the conceptual and final designs. Analyses of the system's load and dynamics are presented.

  8. Prediction of broadband noise from large horizontal axis wind turbine generators

    NASA Technical Reports Server (NTRS)

    Grosveld, F. W.

    1984-01-01

    A method is presented for predicting the broadband noise spectra of large horizontal axis wind turbine generators. It includes contributions from such noise sources as the inflow turbulence to the rotor, the interactions between the turbulent boundary layers on the blade surfaces with their trailing edges and the wake due to a blunt trailing edge. The method is partly empirical and is based on acoustic measurements of large wind turbines and airfoil models. The predicted frequency spectra are compared with measured data from several machines including the MOD-OA, the MOD-2, the WTS-4 and the U.S. Wind-power Inc. machine. Also included is a broadband noise prediction for the proposed MOD-5B. The significance of the effects of machine size, power output, trailing edge bluntness and distance to the receiver is illustrated. Good agreement is obtained between the predicted and measured far field noise spectra.

  9. Measurement and prediction of broadband noise from large horizontal axis wind turbine generators

    NASA Technical Reports Server (NTRS)

    Grosveld, F. W.; Shepherd, K. P.; Hubbard, H. H.

    1995-01-01

    A method is presented for predicting the broadband noise spectra of large wind turbine generators. It includes contributions from such noise sources as the inflow turbulence to the rotor, the interactions between the turbulent boundary layers on the blade surfaces with their trailing edges and the wake due to a blunt trailing edge. The method is partly empirical and is based on acoustic measurements of large wind turbines and airfoil models. Spectra are predicted for several large machines including the proposed MOD-5B. Measured data are presented for the MOD-2, the WTS-4, the MOD-OA, and the U.S. Windpower Inc. machines. Good agreement is shown between the predicted and measured far field noise spectra.

  10. Simulation Tool to Assess Mechanical and Electrical Stresses on Wind Turbine Generators: Preprint

    SciTech Connect

    Singh, M.; Muljadi, E.; Gevorgian, V.; Jonkman, J.

    2013-10-01

    Wind turbine generators (WTGs) consist of many different components to convert kinetic energy of the wind into electrical energy for end users. Wind energy is accessed to provide mechanical torque for driving the shaft of the electrical generator. The conversion from wind power to mechanical power is governed by the aerodynamic conversion. The aerodynamic-electrical-conversion efficiency of a WTGis influenced by the efficiency of the blades, the gearbox, the generator, and the power converter. This paper describes the use of MATLAB/Simulink to simulate the electrical and grid-related aspects of a WTG coupled with the FAST aero-elastic wind turbine computer-aided engineering tool to simulate the aerodynamic and mechanical aspects of a WTG. The combination of the two enables studiesinvolving both electrical and mechanical aspects of a WTG. This digest includes some examples of the capabilities of the FAST and MATLAB coupling, namely the effects of electrical faults on the blade moments.

  11. Model OA Wind Turbine Generator FEMA (Failure Modes and Effects Analysis)

    SciTech Connect

    Klein, W.E. . Plum Brook Station); Lalli, V.R. . Lewis Research Center)

    1989-10-01

    This report presents the results of Failure Modes and Effects Analysis (FMEA) conducted for the Wind Turbine Generators. The FMEA was performed for the functional modes of each system, subsystem, or component. The single-point failures were eliminated for most of the systems. The blade system was the only exception. The qualitative probability of a blade separating was estimated at Level D-remote. Many changes were made to the hardware as a result of this analysis. The most significant change was the addition of the safety system. Operational experience and need to improve machine availability have resulted in subsequent changes to the various systems which are also reflected in this FMEA. 2 refs., 3 figs.

  12. Background and system description of the Mod 1 wind turbine generator

    NASA Technical Reports Server (NTRS)

    Ernst, E. H.

    1978-01-01

    The Mod-1 wind turbine considered is a large utility-class machine, operating in the high wind regime, which has the potential for generation of utility grade power at costs competitive with other alternative energy sources. A Mod-1 wind turbine generator (WTG) description is presented, taking into account the two variable-pitch steel blades of the rotor, the drive train, power generation/control, the Nacelle structure, and the yaw drive. The major surface elements of the WTG are the ground enclosure, the back-up battery system, the step-up transformer, elements of the data system, cabling, area lighting, and tower foundation. The final system weight (rotor, Nacelle, and tower) is expected to be about 650,000 pounds. The WTG will be capable of delivering 1800 kW to the utility grid in a wind-speed above 25 mph.

  13. Dynamics of a Flywheel Energy Storage System Supporting a Wind Turbine Generator in a Microgrid

    NASA Astrophysics Data System (ADS)

    Nair S, Gayathri; Senroy, Nilanjan

    2016-02-01

    Integration of an induction machine based flywheel energy storage system with a wind energy conversion system is implemented in this paper. The nonlinear and linearized models of the flywheel are studied, compared and a reduced order model of the same simulated to analyze the influence of the flywheel inertia and control in system response during a wind power change. A quantification of the relation between the inertia of the flywheel and the controller gain is obtained which allows the system to be considered as a reduced order model that is more controllable in nature. A microgrid setup comprising of the flywheel energy storage system, a two mass model of a DFIG based wind turbine generator and a reduced order model of a diesel generator is utilized to analyse the microgrid dynamics accurately in the event of frequency variations arising due to wind power change. The response of the microgrid with and without the flywheel is studied.

  14. Employing static excitation control and tie line reactance to stabilize wind turbine generators

    NASA Technical Reports Server (NTRS)

    Hwang, H. H.; Mozeico, H. V.; Guo, T.

    1978-01-01

    An analytical representation of a wind turbine generator is presented which employs blade pitch angle feedback control. A mathematical model was formulated. With the functioning MOD-0 wind turbine serving as a practical case study, results of computer simulations of the model as applied to the problem of dynamic stability at rated load are also presented. The effect of the tower shadow was included in the input to the system. Different configurations of the drive train, and optimal values of the tie line reactance were used in the simulations. Computer results revealed that a static excitation control system coupled with optimal values of the tie line reactance would effectively reduce oscillations of the power output, without the use of a slip clutch.

  15. The MOD-OA 200 kilowatt wind turbine generator design and analysis report

    NASA Technical Reports Server (NTRS)

    Andersen, T. S.; Bodenschatz, C. A.; Eggers, A. G.; Hughes, P. S.; Lampe, R. F.; Lipner, M. H.; Schornhorst, J. R.

    1980-01-01

    The project requirements, approach, system description, design requirements, design, analysis, system tests, installation safety considerations, failure modes and effects analysis, data acquisition, and initial performance for the MOD-OA 200 kw wind turbine generator are discussed. The components, the rotor, driven train, nacelle equipment, yaw drive mechanism and brake, tower, foundation, electrical system, and control systems are presented. The rotor includes the blades, hub and pitch change mechanism. The drive train includes the low speed shaft, speed increaser, high speed shaft, and rotor brake. The electrical system includes the generator, switchgear, transformer, and utility connection. The control systems are the blade pitch, yaw, and generator control, and the safety system. Manual, automatic, and remote control and Dynamic loads and fatigue are analyzed.

  16. Conceptual design of the 7 megawatt Mod-5B wind turbine generator

    NASA Technical Reports Server (NTRS)

    Douglas, R. R.

    1982-01-01

    Similar to MOD-2, the MOD-5B wind turbine generator system is designed for the sole purpose of providing electrical power for distribution by a major utility network. The objectives of the MOD-2 and MOD-5B programs are essentially identical with one important exception; the cost-of-electricity (COE) target is reduced from 4 cent/Kwhr on MOD-2 to 3 cent/Kwhr on MOD-5B, based on mid 1977 dollars and large quantity production. The MOD-5B concept studies and eventual concept selection confirmed that the program COE targets could not only be achieved but substantially bettered. Starting from the established MOD-2 technology as a base, this achievement resulted from a combination of concept changes, size changes, and design refinements. The result of this effort is a wind turbine system that can compete with conventional power generation over significant geographical areas, increasing commercial market potential by an order of magnitude.

  17. Noise measurements for single and multiple operation of 50 kw wind turbine generators

    NASA Technical Reports Server (NTRS)

    Hubbard, H. H.; Shepherd, K. P.

    1982-01-01

    The noise characteristics of the U.S. Windpower Inc., 50 kw wind turbine generator were measured at various distances from 30 m to 1100 m and for a range of output power. The generated noise is affected by the aerodynamic wakes of the tower legs at frequencies below about 120 Hz and the blade trailing edge thickness at frequencies of about 2 kHz. Rope strakes and airfoil fairings on the legs did not result in substantial noise reductions. Sharpening the blade trailing edges near the tip was effective in reducing broad band noise near 2 kHz. For multiple machines the sound fields are superposed. A three-fold increase in number of machines (from 1 to 3) results in a predicted increase in he sound pressure level of about 5 dB. The detection threshold for 14 machines operating in a 13 - 20 mph wind is observed to be at approximately 1160 m in the downwind direction.

  18. Mod-5A wind turbine generator program design report. Volume 2: Conceptual and preliminary design, book 2

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The design, development and analysis of the 7.3 MW MOD-5A wind tunnel generator is documented. There are four volumes. In Volume 2, book 2 the requirements and criteria for the design are presented. The development tests, which determined or characterized many of the materials and components of the wind turbine generator, are described.

  19. Synchronization of the ERDA-NASA 100 LkW wind turbine generator with large utility networks

    NASA Technical Reports Server (NTRS)

    Hwang, H. H.; Gilbert, L. J.

    1977-01-01

    The synchronizing of a wind turbine generator against an infinite bus under random conditions is studied. With a digital computer, complete solutions for rotor speed, generator power angle, electromagnetic torque, wind turbine torque, wind turbine blade pitch angle, and armature current are obtained and presented by graphs.

  20. Wind turbine generator interaction with diesel generators on an isolated power system

    SciTech Connect

    Scott, G.W.; Wilreker, V.F.

    1983-01-01

    The results of a dynamic interaction investigation to characterize any disturbances caused by interfacing the Mod 0A wind turbine (150 kW configuration) with the Block Island utility diesel generator grid are reported. The tests were run when only two diesel generators were on line, and attention was given to power, frequency, and voltage time profiles. The interconnected system was examined in the start-up and synchronization phase, normal shutdown and cut-out of the wind turbine, during fixed pitch generation, and during variable pitch operation. Governors were installed on the diesel generators to accommodate the presence of wind-derived electricity. The blade pitch control was set to maintain power at 150 kW or below. Power and voltage transients were insignificant during start-up and shutdown, and frequency aberrations were within the range caused by load fluctuations. It is concluded that wind turbine generation can be successfully implemented by an isolated utility, even with a significant penetration to the total grid output. 5 references.

  1. Conceptual design of a fixed-pitch wind turbine generator system rated at 400 kilowatts

    NASA Technical Reports Server (NTRS)

    Pintz, A.; Kasuba, R.; Spring, J.

    1984-01-01

    The design and cost aspects of a fixed pitch, 400 kW Wind Turbine Generator (WTG) concept are presented. Improvements in reliability and cost reductions were achieved with fixed pitch operation and by incorporating recent advances in WTG technology. The specifications for this WTG concept were as follows: (1) A fixed pitch, continuous wooden rotor was to be provided by the Gougeon Bros. Co. (2) An 8 leg hyperboloid tower that showed promise as a low cost structure was to be used. (3) Only commercially available components and parts that could be easily fabricated were to be considered. (4) Design features deemed desirable based on recent NASA research efforts were to be incorporated. Detailed costs and weight estimates were prepared for the second machine and a wind farm of 12 WTG's. The calculated cost of energy for the fixed pitch, twelve unit windfarm is 11.5 cents/kW hr not including the cost of land and access roads. The study shows feasibility of fixed pitch, intermediate power WTG operation.

  2. Design of a 3 kW wind turbine generator with thin airfoil blades

    SciTech Connect

    Ameku, Kazumasa; Nagai, Baku M.; Roy, Jitendro Nath

    2008-09-15

    Three blades of a 3 kW prototype wind turbine generator were designed with thin airfoil and a tip speed ratio of 3. The wind turbine has been controlled via two control methods: the variable pitch angle and by regulation of the field current of the generator and examined under real wind conditions. The characteristics of the thin airfoil, called ''Seven arcs thin airfoil'' named so because the airfoil is composed of seven circular arcs, are analyzed with the airfoil design and analysis program XFOIL. The thin airfoil blade is designed and calculated by blade element and momentum theory. The performance characteristics of the machine such as rotational speed, generator output as well as stability for wind speed changes are described. In the case of average wind speeds of 10 m/s and a maximum of 19 m/s, the automatically controlled wind turbine ran safely through rough wind conditions and showed an average generator output of 1105 W and a power coefficient 0.14. (author)

  3. MOD-0A 200 kW wind turbine generator design and analysis report

    NASA Technical Reports Server (NTRS)

    Anderson, T. S.; Bodenschatz, C. A.; Eggers, A. G.; Hughes, P. S.; Lampe, R. F.; Lipner, M. H.; Schornhorst, J. R.

    1980-01-01

    The design, analysis, and initial performance of the MOD-OA 200 kW wind turbine generator at Clayton, NM is documented. The MOD-OA was designed and built to obtain operation and performance data and experience in utility environments. The project requirements, approach, system description, design requirements, design, analysis, system tests, installation, safety considerations, failure modes and effects analysis, data acquisition, and initial performance for the wind turbine are discussed. The design and analysis of the rotor, drive train, nacelle equipment, yaw drive mechanism and brake, tower, foundation, electricl system, and control systems are presented. The rotor includes the blades, hub, and pitch change mechanism. The drive train includes the low speed shaft, speed increaser, high speed shaft, and rotor brake. The electrical system includes the generator, switchgear, transformer, and utility connection. The control systems are the blade pitch, yaw, and generator control, and the safety system. Manual, automatic, and remote control are discussed. Systems analyses on dynamic loads and fatigue are presented.

  4. Measured effects of wind turbine generation at the Block Island Power Company

    NASA Technical Reports Server (NTRS)

    Wilreker, V. F.; Smith, R. F.; Stiller, P. H.; Scot, G. W.; Shaltens, R. K.

    1984-01-01

    Data measurements made on the NASA MOD-OA 200-kw wind-turbine generator (WTG) installed on a utility grid form the basis for an overall performance analysis. Fuel displacement/-savings, dynamic interactions, and WTG excitation (reactive-power) control effects are studied. Continuous recording of a large number of electrical and mechanical variables on FM magnetic tape permit evaluation and correlation of phenomena over a bandwidth of at least 20 Hz. Because the wind-power penetration reached peaks of 60 percent, the impact of wind fluctuation and wind-turbine/diesel-utility interaction is evaluated in a worst-case scenario. The speed-governor dynamics of the diesel units exhibited an underdamped response, and the utility operation procedures were not altered to optimize overall WTG/utility performance. Primary findings over the data collection period are: a calculated 6.7-percent reduction in fuel consumption while generating 11 percent of the total electrical energy; acceptable system voltage and frequency fluctuations with WTG connected; and applicability of WTG excitation schemes using voltage, power, or VARS as the controlled variable.

  5. Wind turbine generator interaction with diesel generators on an isolated power system

    NASA Technical Reports Server (NTRS)

    Scott, G. W.; Wilreker, V. F.; Shaltens, R. K.

    1983-01-01

    The results of a dynamic interaction investigation to characterize any disturbances caused by interfacing the Mod 0A wind turbine (150 kW configuration) with the Block Island utility diesel generator grid are reported. The tests were run when only two diesel generators were on line, and attention was given to power, frequency, and voltage time profiles. The interconnected system was examined in the start-up and synchronization phase, normal shutdown and cut-out of the wind turbine, during fixed pitch generation, and during variable pitch operation. Governors were installed on the diesel generators to accommodate the presence of wind-derived electricity. The blade pitch control was set to maintain power at 150 kW or below. Power and voltage transients were insignificant during start-up and shutdown, and frequency aberrations were within the range caused by load fluctuations. It is concluded that wind turbine generation can be successfully implemented by an isolated utility, even with a significant penetration to the total grid output.

  6. Wind Turbine Generator System Acoustic Noise Test Report for the Gaia Wind 11-kW Wind Turbine

    SciTech Connect

    Huskey, A.

    2011-11-01

    This report details the acoustic noise test conducted on the Gaia-Wind 11-kW wind turbine at the National Wind Technology Center. The test turbine is a two- bladed, downwind wind turbine with a rated power of 11 kW. The test turbine was tested in accordance with the International Electrotechnical Commission standard, IEC 61400-11 Ed 2.1 2006-11 Wind Turbine Generator Systems -- Part 11 Acoustic Noise Measurement Techniques.

  7. Infrared thermal wave nondestructive testing for rotor blades in wind turbine generators non-destructive evaluation and damage monitoring

    NASA Astrophysics Data System (ADS)

    Zhao, Shi bin; Zhang, Cun-lin; Wu, Nai-ming; Duan, Yu-xia; Li, Hao

    2009-07-01

    The rotor blades are key components in wind turbine generators. A visual inspection of the laminated shells for delaminations, air pockets, missing/disoriented fabric etc. is in most cases also not possible due to the manufacturing process, so Non-destructive testing and evaluation (NDT & E) techniques for assessing the integrity of rotor blades structure are essential to both reduce manufacturing costs and out of service time of wind turbine generators due to maintenance. Nowadays, Infrared Thermal Wave Nondestructive Testing (Pulsed thermography) is commonly used for assessing composites. This research work utilizes Infrared Thermal Wave Nondestructive Testing system (EchoTherm, Thermal Wave Imaging, Inc.) to inspect a specimen with embedded defects (i.e. foreign matter and air inclusions) in different depth which is a part of rotor blades in wind turbine generators, we have successfully identified defects including foreign matter and air inclusions, and discovered a defective workmanship. The system software allows us to simultaneously view and analyze the results for an entire transition.

  8. WTG Energy Systems' MP1-200 200 kilowatt wind turbine generator. [a fixed pitch rotor configuration driving a synchronous generator

    NASA Technical Reports Server (NTRS)

    Spaulding, A. P., Jr.

    1979-01-01

    The preliminary design criteria of the MP1-200 wind turbine are given along with a brief description of the wind turbine generator. Performance and operational experience and cost factors are included. Recommendations for additional research are listed.

  9. Preliminary analysis of the audible noise of constant-speed, horizontal-axis wind-turbine generators

    SciTech Connect

    Keast, D. N.; Potter, R. C.

    1980-07-01

    An analytical procedure has been developed for calculating certain aerodynamic sound levels produced by large, horizontal-axis wind-turbine generators (WTG's) such as the DOE/NASA Mods-0, -0A, -1, and -2. This preliminary procedure is based upon very limited field data from the Mod-0. It postulates a noise component due to the (constant) rotation of the blades of the WTG, plus a wake-noise component that increases with the square of the power produced by the WTG. Mechanical sound from machinery, and low-frequency impulsive sounds produced by blade interaction with the wake of the support tower are not considered.

  10. Synchronization of the ERDA-NASA 100 kW wind turbine generator with large utility networks

    NASA Technical Reports Server (NTRS)

    Hwang, H. H.; Gilbert, L. J.

    1977-01-01

    The synchronizing of a wind turbine generator against an infinite bus under random conditions is studied for the first time. With a digital computer, complete solutions for rotor speed, generator power angle, electromagnetic torque, wind turbine torque, wind turbine blade pitch angle, and armature current are obtained and presented by graphs. Experiments have been recently performed on the ERDA-NASA 100 kW wind turbine. Experimental results matched computer study results very closely and confirmed that the synchronization can be accomplished by means of the existing speed control system and an automatic synchronizer.

  11. Estimating of a nonlinear power curve for a Wind Turbine Generator

    NASA Astrophysics Data System (ADS)

    Calif, R.; Schmitt, F. G.

    2012-04-01

    The output power from a Wind Turbine Generator (WTG) is an intermittent resource, due to the high variability of the atmospheric wind at all spatial or temporal scales ranging from large scale variations to very short variations. Generally, a function transfer or a power curve of WTG is estimated with the IEC standard 61400 - 12 giving a relation of coupling between the measured wind speed and the output power for the considered WTG. However, this relation is a statistical representation and not takes into account the dynamics of the power output, more precisely on small time scales. The goal is to provide a method to estimate and to model the function transfer of a WTG, in order to synthesize the output power mimicking the statistical and the dynamical properties of the real output power. For that, we study the statistics of power curve in the multifractal framework motivated by the presence of spectral scaling for the wind speed and the output power data from a WTG. The first step consists to quantify the power curve or the transfer function of two intermittent stochastic processes such as the wind speed u(t) and the output power p(t) at all temporal scales and at all intensities. In this study, firstly, we define the time increment of the wind speed measurement u'(t) = u(t + τ) - u(t) and the time increment of the output power measurement p'(t) = p(t + τ) - p(t) characterized by mth and nth order structure functions to estimate the exponent functions ζu'(m) and ζp'(n) that characterize respectively the multifractal properties of the wind speed fluctuations u'(t) and the output power fluctuations p'(t) from the WTG. The exponent function ζ defines the types of scaling behavior of a process: if ζ is linear the statistical behavior is monoscaling corresponding to a monofractal process. If ζ is nonlinear and concave, the statistical behavior is multiscaling corresponding to a multifractal process. The concavity of this function is a characteristic of the

  12. A Study on the Matching between the Straight Wing Non-articulated Vertical Axis Wind Turbine and the New Wind Turbine Generator

    NASA Astrophysics Data System (ADS)

    Siota, Takasi; Isaka, Tsutomu; Sano, Takashi; Seki, Kazuichi

    In the current wind turbine generation system, there are substantial problems such as the maximum power of the wind turbine cannot be obtained under the fluctuating wind speed, high in cost and low in annual net electricity production (due to mismatch between a generator and a wind turbine). A new wind turbine generator optimized for the wind turbine output is presented in order to solve such problems. This wind turbine generator consists of a permanent magnet generator, a reactor and a rectifier, and uses neither a control circuit which requires standby electricity nor a PWM converter having a switching element. By selecting most appropriate combination of the permanent magnet generator having multiple windings and the reactor connected in series with each winding, the maximum output of the wind turbine can be obtained without using a control circuit. The new wind turbine generator was directly coupled with the straight wing non-articulated vertical axis wind turbine (SW-VAWT), and matching of the generator with the wind turbine was examined through field tests. From the test result and review, it has been confirmed that the new wind turbine generator is highly matched with the wind turbine under the fluctuating wind speed.

  13. Design of a control scheme for a maximum power extraction in low power wind turbine-generator system

    NASA Astrophysics Data System (ADS)

    Henao Bravo, Elkin Edilberto

    This document presents the modeling of a wind turbine-generator system and developing a control scheme for maximum power extraction. The system comprises a low-power variable speed wind rotor coupled to a squirrel cage induction generator through gearbox. The generator delivers electrical energy to a DC load through a PWM three phase rectifier which control variables are duty cycle and the fundamental frequency of the modulated signal. The control scheme maintains constant relationship voltage/frequency in the stator of the generator to operate the machine with constant air gap flow at its nominal value, thereby decreasing electrical losses in the circuit of the stator and rotor. The controller is based on MPPT algorithms for determining the operating point the system and achieve the proper mechanical speed shaft. The performance is evaluated through simulations in MatlabRTM/simulink. and presents this type of control as a good alternative for handling low-power wind turbine-generator systems effectively and efficiently

  14. Response measurements for two building structures excited by noise from a large horizontal axis wind turbine generator

    NASA Technical Reports Server (NTRS)

    Hubbard, H. H.; Shepherd, K. P.

    1984-01-01

    Window and wall acceleration measurements and interior noise measurements ere made for two different building structures during excitation by noise from the WTS-4 horizontal axis wind turbine generator operating in a normal power generation mode. With turbine noise input pulses resulted in acceleration pulses for the wall and window elements of the two tests buildings. Response spectra suggest that natural vibration modes of the structures are excited. Responses of a house trailer were substantially greater than those for a building of sturdier construction. Peak acceleration values correlate well with similar data for houses excited by flyover noise from commercial and military airplanes and helicopters, and sonic booms from supersonic aircraft. Interior noise spectra have peaks at frequencies corresponding to structural vibration modes and room standing waves; and the levels for particular frequencies and locations can be higher than the outside levels.

  15. A probability evaluation method of early deterioration condition for the critical components of wind turbine generator systems

    NASA Astrophysics Data System (ADS)

    Hu, Yaogang; Li, Hui; Liao, Xinglin; Song, Erbing; Liu, Haitao; Chen, Z.

    2016-08-01

    This study determines the early deterioration condition of critical components for a wind turbine generator system (WTGS). Due to the uncertainty nature of the fluctuation and intermittence of wind, early deterioration condition evaluation poses a challenge to the traditional vibration-based condition monitoring methods. Considering the its thermal inertia and strong anti-interference capacity, temperature characteristic parameters as a deterioration indication cannot be adequately disturbed by the uncontrollable noise and uncertainty nature of wind. This paper provides a probability evaluation method of early deterioration condition for critical components based only on temperature characteristic parameters. First, the dynamic threshold of deterioration degree function was proposed by analyzing the operational data between temperature and rotor speed. Second, a probability evaluation method of early deterioration condition was presented. Finally, two cases showed the validity of the proposed probability evaluation method in detecting early deterioration condition and in tracking their further deterioration for the critical components.

  16. A Study on the Observation of Direct Lightning Current through the Wind Turbine Generator System in the Coast of the Japan Sea

    NASA Astrophysics Data System (ADS)

    Shiraishi, Yasuhiro; Otsuka, Takahiro; Matsuura, Hideki

    As clean energy that solves energy resources, many wind turbine generator systems have developed up to now, in Japan. The generation capacity of wind power is above 1 million kW, and the construction also continues from now on. The wind turbine generator systems are built in the good place of the wind condition, and those many are built on the coast of the Japan Sea. However, the coast of the Japan Sea is known as a place with much winter lightning, and wind turbine generator systems also often suffer the damage by winter lightning. The authors observed the lightning current that strikes through the wind turbine generator systems directly, in order to establish on the lightning protection of them. The authors acquired dozens of data as a result of observation in Akita Japan for 17 months. Based on these data, some considerations were performed about the performance of winter lightning that struck through the wind turbine generator systems. As the result of consideration, we found some interesting knowledge following sentence. It made clear anew that the tower which is a place of high position from the ground and on the windward has much number of lightning flash and many total flash charges. The lightning stroke current divided the tower pipe and ground leads. About 70% of the observed lightning current flowed to the tower pipe, and about 30% is divided into two grounding leads connected to the leg of tower. All of steep current that is on a wave front flow a tower side, it dose not flow to a grounding leads side. The distributions of lightning parameters between our observation results and past one are in good conformity.

  17. Control system design for the MOD-5A 7.3 mW wind turbine generator

    NASA Technical Reports Server (NTRS)

    Barton, Robert S.; Hosp, Theodore J.; Schanzenbach, George P.

    1995-01-01

    This paper provides descriptions of the requirements analysis, hardware development and software development phases of the Control System design for the MOD-5A 7.3 mW Wind Turbine Generator. The system, designed by General Electric Company, Advanced Energy Programs Department, under contract DEN 3-153 with NASA Lewis Research Center and DOE, provides real time regulation of rotor speed by control of both generator torque and rotor torque. A variable speed generator system is used to provide both airgap torque control and reactive power control. The wind rotor is designed with segmented ailerons which are positioned to control blade torque. The central component of the control system, selected early in the design process, is a programmable controller used for sequencing, alarm monitoring, communication, and real time control. Development of requirements for use of aileron controlled blades and a variable speed generator required an analytical simulation that combined drivetrain, tower and blade elastic modes with wind disturbances and control behavior. An orderly two phase plan was used for controller software development. A microcomputer based turbine simulator was used to facilitate hardware and software integration and test.

  18. Serially-Connected Compensator for Eliminating the Unbalanced Three-Phase Voltage Impact on Wind Turbine Generators: Preprint

    SciTech Connect

    Wu, Z.; Hsu, P.; Muljadi, E.; Gao, W.

    2015-04-06

    Untransposed transmission lines, unbalanced tap changer operations, and unbalanced loading in weak distribution lines can cause unbalanced-voltage conditions. The resulting unbalanced voltage at the point of interconnection affects proper gird integration and reduces the lifetime of wind turbines due to power oscillations, torque pulsations, mechanical stresses, energy losses, and uneven and overheating of the generator stator winding. This work investigates the dynamic impact of unbalanced voltage on the mechanical and electrical components of integrated Fatigue, Aerodynamics, Structures, and Turbulence (FAST) wind turbine generation systems (WTGs) of Type 1 (squirrel-cage induction generator) and Type 3 (doubly-fed induction generator). To alleviate this impact, a serially-connected compensator for a three-phase power line is proposed to balance the wind turbine-side voltage. Dynamic simulation studies are conducted in MATLAB/Simulink to compare the responses of these two types of wind turbine models under normal and unbalanced-voltage operation conditions and demonstrate the effectiveness of the proposed compensator.

  19. Performance and load data from Mod-0A and Mod-1 wind turbine generators

    NASA Technical Reports Server (NTRS)

    Spera, D. A.; Janetzke, D. C.

    1982-01-01

    Experimental data, together with supporting analysis, are presented on the power conversion performance and blade loading of large, horizontal-axis wind turbines tested at electric utility sites in the U.S. Four turbine rotor configurations, from 28 to 61 meters in diameter, and data from five test sites are included. Performance data are presented in the form of graphs of power and system efficiency versus free-stream wind speed. Deviations from theoretical performance are analyzed statistically. Power conversion efficiency averaged 0.34 for all tests combined, compared with 0.31 predicted. Round blade tips appeared to improve performance significantly. Cyclic blade loads were normalized to develop load factors which can be used in the design of rotors with rigid hubs.

  20. A 200-kW wind turbine generator conceptual design study

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A conceptual design study was conducted to define a 200 kW wind turbine power system configuration for remote applications. The goal was to attain an energy cost of 1 to 2 cents per kilowatt-hour at a 14-mph site (mean average wind velocity at an altitude of 30 ft.) The costs of the Clayton, New Mexico, Mod-OA (200-kW) were used to identify the components, subsystems, and other factors that were high in cost and thus candidates for cost reduction. Efforts devoted to developing component and subsystem concepts and ideas resulted in a machine concept that is considerably simpler, lighter in weight, and lower in cost than the present Mod-OA wind turbines. In this report are described the various innovations that contributed to the lower cost and lighter weight design as well as the method used to calculate the cost of energy.

  1. Wind Turbine Generator System Duration Test Report for the ARE 442 Wind Turbine

    SciTech Connect

    van Dam, J.; Baker, D.; Jager, D.

    2010-05-01

    This test is being conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. This project was established to help reduce the barriers of wind energy expansion by providing independent testing results for small turbines. In total, four turbines are being tested at the NWTC as a part of this project. Duration testing is one of up to 5 tests that may be performed on the turbines, including power performance, safety and function, noise, and power quality tests. The results of the testing provide manufacturers with reports that may be used for small wind turbine certification. The test equipment includes a grid connected ARE 442 wind turbine mounted on a 30.5 meter (100 ft) lattice tower manufactured by Abundant Renewable Energy. The system was installed by the NWTC Site Operations group with guidance and assistance from Abundant Renewable Energy.

  2. NREL Controllable Grid Interface for Testing MW-Scale Wind Turbine Generators (Poster)

    SciTech Connect

    McDade, M.; Gevorgian, V.; Wallen, R.; Erdman, W.

    2013-04-01

    In order to understand the behavior of wind turbines experiencing grid disturbances, it is necessary to perform a series of tests and accurate transient simulation studies. The latest edition of the IEC 61400-21 standard describes methods for such tests that include low voltage ride-through (LVRT), active power set-point control, ramp rate limitations, and reactive power capability tests. The IEC methods are being widely adopted on both national and international levels by wind turbine manufacturers, certification authorities, and utilities. On-site testing of wind turbines might be expensive and time consuming since it requires both test equipment transportation and personnel presence in sometimes remote locations for significant periods of time because such tests need to be conducted at certain wind speed and grid conditions. Changes in turbine control software or design modifications may require redoing of all tests. Significant cost and test-time reduction can be achieved if these tests are conducted in controlled laboratory environments that replicate grid disturbances and simulation of wind turbine interactions with power systems. Such testing capability does not exist in the United States today. An initiative by NREL to design and construct a 7-MVA grid simulator to operate with the existing 2.5 MW and new upcoming 5-MW dynamometer facilities will fulfill this role and bring many potential benefits to the U.S. wind industry with the ultimate goal of reducing wind energy integration costs.

  3. Superconducting wind turbine generators

    NASA Astrophysics Data System (ADS)

    Abrahamsen, A. B.; Mijatovic, N.; Seiler, E.; Zirngibl, T.; Træholt, C.; Nørgård, P. B.; Pedersen, N. F.; Andersen, N. H.; Østergård, J.

    2010-03-01

    We have examined the potential of 10 MW superconducting direct drive generators to enter the European offshore wind power market and estimated that the production of about 1200 superconducting turbines until 2030 would correspond to 10% of the EU offshore market. The expected properties of future offshore turbines of 8 and 10 MW have been determined from an up-scaling of an existing 5 MW turbine and the necessary properties of the superconducting drive train are discussed. We have found that the absence of the gear box is the main benefit and the reduced weight and size is secondary. However, the main challenge of the superconducting direct drive technology is to prove that the reliability is superior to the alternative drive trains based on gearboxes or permanent magnets. A strategy of successive testing of superconducting direct drive trains in real wind turbines of 10 kW, 100 kW, 1 MW and 10 MW is suggested to secure the accumulation of reliability experience. Finally, the quantities of high temperature superconducting tape needed for a 10 kW and an extreme high field 10 MW generator are found to be 7.5 km and 1500 km, respectively. A more realistic estimate is 200-300 km of tape per 10 MW generator and it is concluded that the present production capacity of coated conductors must be increased by a factor of 36 by 2020, resulting in a ten times lower price of the tape in order to reach a realistic price level for the superconducting drive train.

  4. Large wind turbine generators

    NASA Technical Reports Server (NTRS)

    Thomas, R. L.; Donovon, R. M.

    1978-01-01

    The development associated with large wind turbine systems is briefly described. The scope of this activity includes the development of several large wind turbines ranging in size from 100 kW to several megawatt levels. A description of the wind turbine systems, their programmatic status and a summary of their potential costs is included.

  5. Experience and assessment of the DOE-NASA Mod-1 2000-Kilowatt wind turbine generator at Boone, North Carolina

    NASA Technical Reports Server (NTRS)

    Collins, J. L.; Shaltenc, R. K.; Poor, R. H.; Barton, R. S.

    1982-01-01

    The Mod 1 program objectives are defined. The Mod 1 wind turbine is described. In addition to the steel blade operated on the wind turbine, a composite blade was designed and manufactured. During the early phase of the manufacturing cycle of Mod 1A configuration was designed that identified concepts such as partial span control, a soft tower, and upwind teetered rotors that were incorporated in second and third generation industry designs. The Mod 1 electrical system performed as designed, with voltage flicker characteristics within acceptable utility limits. Power output versus wind speed equaled or exceeded design predictions. The wind turbine control system was operated successfully at the site and remotely from the utility dispatcher's office. During wind turbine operations, television interference was experienced by the local residents. As a consequence, operations were restricted. Although not implemented, two potential solutions were identified. In addition to television interference, a few local residents complained bout objectionable sound, particularly the 'thump' as the blade passed behind the tower. To eliminate objections, the sound generation level was reduced by 10 dB by reducing the rotor speed from 35 rpm to 23 rpm. Bolts in the drive train fractured. A solution was identified but not implemented. The public reaction toward the Mod 1 wind turbine program was overwhelmingly favorable.

  6. Wind Turbine Generator System Duration Test Report for the Gaia-Wind 11 kW Wind Turbine

    SciTech Connect

    Huskey, A.; Bowen, A.; Jager, D.

    2010-09-01

    This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. This project was established to help reduce the barriers of wind energy expansion by providing independent testing results for small turbines. In total, five turbines are being tested at the National Renewable Energy Laboratory's (NRELs) National Wind Technology Center (NWTC) as a part of this project. Duration testing is one of up to five tests that may be performed on the turbines, including power performance, safety and function, noise, and power quality tests. The results of the testing will provide the manufacturers with reports that may be used for small wind turbine certification. The test equipment includes a Gaia-Wind 11 kW wind turbine mounted on an 18 m monopole tower. Gaia-Wind Ltd. manufactured the turbine in Denmark, although the company is based in Scotland. The system was installed by the NWTC Site Operations group with guidance and assistance from Gaia-Wind.

  7. System Impact Study of the Eastern Grid of Sumba Island, Indonesia: Steady-State and Dynamic System Modeling for the Integration of One and Two 850-kW Wind Turbine Generators

    SciTech Connect

    Oswal, R.; Jain, P.; Muljadi, Eduard; Hirsch, Brian; Castermans, B.; Chandra, J.; Raharjo, S.; Hardison, R.

    2016-01-01

    The goal of this project was to study the impact of integrating one and two 850-kW wind turbine generators into the eastern power system network of Sumba Island, Indonesia. A model was created for the 20-kV distribution network as it existed in the first quarter of 2015 with a peak load of 5.682 MW. Detailed data were collected for each element of the network. Load flow, short-circuit, and transient analyses were performed using DIgSILENT PowerFactory 15.2.1.

  8. Composite rotor blades for wind turbine generators

    NASA Astrophysics Data System (ADS)

    Weigel, W. D.

    The materials, techniques, and methods used to construct a 150 ft test blade, two 31 ft blades for a 40 kW WECS, and rotor blades for the Mod-1 wind turbine are described. Considerations of strength, stiffness, and mass distributions, as well as cost, led to the choice of filament wound fiberglass/epoxy material using transverse filament tape which has structural fibers running across the width of the tape. A number of 90 deg windings were added to the rotor after tape winding to provide compaction and hoop strength. Curing comprised five hours at 180 F. The Mod-1 blades were required to match the steel blades in weight, stiffness, deflection, and frequencies. The finished product weighed 20,000 lb and featured a metal tip cap and braided wire trailing edge strap for lightning protection. The 40 kW was a NACA 23018 in the center and 23012 at the tip, while the Mod-1 blade was a NACA 23025 in the center and 23015 at the tip.

  9. An experimental 100 kilowatt wind turbine generator

    NASA Technical Reports Server (NTRS)

    Thomas, R. L.; Puthoff, R. L.; Savino, J. M.; Johnson, W. R.

    1975-01-01

    Experimental generator consists of two blades mounted on 100 foot tower, driving transmission train and electric generator mounted on top of tower. Machine generates 100 kW of electricity at wind speeds from 18 to 60 miles per hour. Yaw control mechanism automatically orients machine into wind.

  10. Design evolution of large wind turbine generators

    NASA Technical Reports Server (NTRS)

    Spera, D. A.

    1979-01-01

    During the past five years, the goals of economy and reliability have led to a significant evolution in the basic design--both external and internal--of large wind turbine systems. To show the scope and nature of recent changes in wind turbine designs, development of three types are described: (1) system configuration developments; (2) computer code developments; and (3) blade technology developments.

  11. Dynamics and stability of wind turbine generators

    NASA Technical Reports Server (NTRS)

    Hinrichsen, E. N.; Nolan, P. J.

    1981-01-01

    Synchronous and induction generators are considered. A comparison is made between wind turbines, steam, and hydro units. The unusual phenomena associated with wind turbines are emphasized. The general control requirements are discussed, as well as various schemes for torsional damping such as speed sensitive stabilizer and blade pitch control. Integration between adjacent wind turbines in a wind farm is also considered.

  12. Wind turbine generator with improved operating subassemblies

    DOEpatents

    Cheney, Jr., Marvin C.

    1985-01-01

    A wind turbine includes a yaw spring return assembly to return the nacelle from a position to which it has been rotated by yawing forces, thus preventing excessive twisting of the power cables and control cables. It also includes negative coning restrainers to limit the bending of the flexible arms of the rotor towards the tower, and stop means on the rotor shaft to orient the blades in a vertical position during periods when the unit is upwind when the wind commences. A pendulum pitch control mechanism is improved by orienting the pivot axis for the pendulum arm at an angle to the longitudinal axis of its support arm, and excessive creep is of the synthetic resin flexible beam support for the blades is prevented by a restraining cable which limits the extent of pivoting of the pendulum during normal operation but which will permit further pivoting under abnormal conditions to cause the rotor to stall.

  13. Mod 1 wind turbine generator failure modes and effects analysis

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A failure modes and effects analysis (FMEA) was directed primarily at identifying those critical failure modes that would be hazardous to life or would result in major damage to the system. Each subsystem was approached from the top down, and broken down to successive lower levels where it appeared that the criticality of the failure mode warranted more detail analysis. The results were reviewed by specialists from outside the Mod 1 program, and corrective action taken wherever recommended.

  14. Lightning accommodation systems for wind turbine generator safety

    NASA Technical Reports Server (NTRS)

    Bankaitis, H.

    1981-01-01

    The wind turbine safety program identifies the naturally occurring lightning phenomenon as a hazard with the potential to cause loss of program objectives, injure personnel, damage system instrumentation, structure or support equipment and facilities. Several candidate methods of lightning accommodation for each blade were designed, analyzed, and tested by submitting sample blade sections to simulated lightning. Lightning accommodation systems for composite blades were individually developed. Their effectiveness was evaluated by submitting the systems to simulated lightning strikes. The test data were analyzed and system designs were reviewed on the basis of the analysis. This activity is directed at defining design and procedural constraints, requirements for safety devices and warning methods, special procedures, protective equipment and personnel training.

  15. Wind turbine generator rotor blade concepts with low cost potential

    NASA Technical Reports Server (NTRS)

    Sullivan, T. L.; Cahill, T. P.; Griffee, D. G., Jr.; Gewehr, H. W.

    1977-01-01

    Four processed for producing blades are examined. Two use filament winding techniques and two involve filling a mold or form to produce all or part of a blade. The processes are described and a comparison is made of cost, material properties, design and free vibration characteristics. Conclusions are made regarding the feasibility of each process to produce low cost, structurally adequate blades.

  16. Wind turbine/generator set and method of making same

    DOEpatents

    Bevington, Christopher M.; Bywaters, Garrett L.; Coleman, Clint C.; Costin, Daniel P.; Danforth, William L.; Lynch, Jonathan A.; Rolland, Robert H.

    2013-06-04

    A wind turbine comprising an electrical generator that includes a rotor assembly. A wind rotor that includes a wind rotor hub is directly coupled to the rotor assembly via a simplified connection. The wind rotor and generator rotor assembly are rotatably mounted on a central spindle via a bearing assembly. The wind rotor hub includes an opening having a diameter larger than the outside diameter of the central spindle adjacent the bearing assembly so as to allow access to the bearing assembly from a cavity inside the wind rotor hub. The spindle is attached to a turret supported by a tower. Each of the spindle, turret and tower has an interior cavity that permits personnel to traverse therethrough to the cavity of the wind rotor hub. The wind turbine further includes a frictional braking system for slowing, stopping or keeping stopped the rotation of the wind rotor and rotor assembly.

  17. Method for changing removable bearing for a wind turbine generator

    DOEpatents

    Bagepalli, Bharat Sampathkumaran; Jansen, Patrick Lee; Gadre, Aniruddha Dattatraya

    2008-04-22

    A wind generator having removable change-out bearings includes a rotor and a stator, locking bolts configured to lock the rotor and stator, a removable bearing sub-assembly having at least one shrunk-on bearing installed, and removable mounting bolts configured to engage the bearing sub-assembly and to allow the removable bearing sub-assembly to be removed when the removable mounting bolts are removed.

  18. Removable bearing arrangement for a wind turbine generator

    DOEpatents

    Bagepalli, Bharat Sampathkumaran; Jansen, Patrick Lee; Gadre, Aniruddha Dattatraya

    2010-06-15

    A wind generator having removable change-out bearings includes a rotor and a stator, locking bolts configured to lock the rotor and stator, a removable bearing sub-assembly having at least one shrunk-on bearing installed, and removable mounting bolts configured to engage the bearing sub-assembly and to allow the removable bearing sub-assembly to be removed when the removable mounting bolts are removed.

  19. Large wind turbine generators. [NASA program status and potential costs

    NASA Technical Reports Server (NTRS)

    Thomas, R. L.; Donovon, R. M.

    1978-01-01

    The large wind turbine portion of the Federal Wind Energy Program consists of two major project efforts: (1) the Mod-0 test bed project for supporting research technology, and (2) the large experimental wind turbines for electric utility applications. The Mod-0 has met its primary objective of providing the entire wind energy program with early operations and performance data. The large experimental wind turbines to be tested in utility applications include three of the Mod-0A (200 kW) type, one Mod-1 (2000 kW), and possibly several of the Mod-2 (2500 kW) designs. This paper presents a description of these wind turbine systems, their programmatic status, and a summary of their potential costs.

  20. Control of wind turbine generators connected to power systems

    NASA Technical Reports Server (NTRS)

    Hwang, H. H.; Mozeico, H. V.; Gilbert, L. J.

    1978-01-01

    A unique simulation model based on a Mode-O wind turbine is developed for simulating both speed and power control. An analytical representation for a wind turbine that employs blade pitch angle feedback control is presented, and a mathematical model is formulated. For Mode-O serving as a practical case study, results of a computer simulation of the model as applied to the problems of synchronization and dynamic stability are provided. It is shown that the speed and output of a wind turbine can be satisfactorily controlled within reasonable limits by employing the existing blade pitch control system under specified conditions. For power control, an additional excitation control is required so that the terminal voltage, output power factor, and armature current can be held within narrow limits. As a result, the variation of torque angle is limited even if speed control is not implemented simultaneously with power control. Design features of the ERDA/NASA 100-kW Mode-O wind turbine are included.

  1. An Automated Summarization Assessment Algorithm for Identifying Summarizing Strategies

    PubMed Central

    Abdi, Asad; Idris, Norisma; Alguliyev, Rasim M.; Aliguliyev, Ramiz M.

    2016-01-01

    Background Summarization is a process to select important information from a source text. Summarizing strategies are the core cognitive processes in summarization activity. Since summarization can be important as a tool to improve comprehension, it has attracted interest of teachers for teaching summary writing through direct instruction. To do this, they need to review and assess the students' summaries and these tasks are very time-consuming. Thus, a computer-assisted assessment can be used to help teachers to conduct this task more effectively. Design/Results This paper aims to propose an algorithm based on the combination of semantic relations between words and their syntactic composition to identify summarizing strategies employed by students in summary writing. An innovative aspect of our algorithm lies in its ability to identify summarizing strategies at the syntactic and semantic levels. The efficiency of the algorithm is measured in terms of Precision, Recall and F-measure. We then implemented the algorithm for the automated summarization assessment system that can be used to identify the summarizing strategies used by students in summary writing. PMID:26735139

  2. Using Text Messaging to Summarize Text

    ERIC Educational Resources Information Center

    Williams, Angela Ruffin

    2012-01-01

    Summarizing is an academic task that students are expected to have mastered by the time they enter college. However, experience has revealed quite the contrary. Summarization is often difficult to master as well as teach, but instructors in higher education can benefit greatly from the rapid advancement in mobile wireless technology devices, by…

  3. A Statistical Approach to Automatic Speech Summarization

    NASA Astrophysics Data System (ADS)

    Hori, Chiori; Furui, Sadaoki; Malkin, Rob; Yu, Hua; Waibel, Alex

    2003-12-01

    This paper proposes a statistical approach to automatic speech summarization. In our method, a set of words maximizing a summarization score indicating the appropriateness of summarization is extracted from automatically transcribed speech and then concatenated to create a summary. The extraction process is performed using a dynamic programming (DP) technique based on a target compression ratio. In this paper, we demonstrate how an English news broadcast transcribed by a speech recognizer is automatically summarized. We adapted our method, which was originally proposed for Japanese, to English by modifying the model for estimating word concatenation probabilities based on a dependency structure in the original speech given by a stochastic dependency context free grammar (SDCFG). We also propose a method of summarizing multiple utterances using a two-level DP technique. The automatically summarized sentences are evaluated by summarization accuracy based on a comparison with a manual summary of speech that has been correctly transcribed by human subjects. Our experimental results indicate that the method we propose can effectively extract relatively important information and remove redundant and irrelevant information from English news broadcasts.

  4. Conceptual design of the 6 MW Mod-5A wind turbine generator

    NASA Technical Reports Server (NTRS)

    Barton, R. S.; Lucas, W. C.

    1982-01-01

    The General Electric Company, Advanced Energy Programs Department, is designing under DOE/NASA sponsorship the MOD-5A wind turbine system which must generate electricity for 3.75 cent/KWH (1980) or less. During the Conceptual Design Phase, completed in March, 1981, the MOD-5A WTG system size and features were established as a result of tradeoff and optimization studies driven by minimizing the system cost of energy (COE). This led to a 400' rotor diameter size. The MOD-5A system which resulted is defined in this paper along with the operational and environmental factors that drive various portions of the design. Development of weight and cost estimating relationships (WCER's) and their use in optimizing the MOD-5A are discussed. The results of major tradeoff studies are also presented. Subsystem COE contributions for the 100th unit are shown along with the method of computation. Detailed descriptions of the major subsystems are given, in order that the results of the various trade and optimization studies can be more readily visualized.

  5. Hybrid Electro-Mechanical Simulation Tool for Wind Turbine Generators: Preprint

    SciTech Connect

    Singh, M.; Muljadi, E.; Jonkman, J.

    2013-05-01

    This paper describes the use of MATLAB/Simulink to simulate the electrical and grid-related aspects of a WTG and the FAST aero-elastic wind turbine code to simulate the aerodynamic and mechanical aspects of the WTG. The combination of the two enables studies involving both electrical and mechanical aspects of the WTG.

  6. Detection of low frequency impulsive noise from large wind turbine generators

    NASA Technical Reports Server (NTRS)

    Shepherd, K. P.

    1985-01-01

    The thresholds of detection of low frequency, impulsive wind turbine sounds in the presence of background noise were examined. Seven wind turbine sounds, six of which were synthesized, were used in conjunction with three background noise conditions; quiet, 35, and 45 dB(A). The results indicate that thresholds of detection are predictable based on assumed characteristics of the auditory system. The synthesized wind turbine sounds were found to adequately represent a real recording.

  7. Noise radiation characteristics of the Westinghouse WWG-0600 (600kW) wind turbine generator

    NASA Technical Reports Server (NTRS)

    Shepherd, Kevin P.; Hubbard, Harvey H.

    1989-01-01

    Acoustic data are presented from five different WWG-0600 machines for the wind speed range 6.7 to 13.4 m/s, for a power output range of 51 to 600 kW and for upwind, downwind and crosswind locations. Both broadband and narrowband data are presented and are compared with calculations and with similar data from other machines. Predicted broadband spectra are in good agreement with measurements at high power and underestimate them at low power. Discrete frequency rotational noise components are present in all measurements and are believed due to terrain induced wind gradients. Predictions are in general agreement with measurements upwind and downwind but underestimate them in the crosswind direction.

  8. Environmental noise characteristics of the MOD5-B (3.2 MW) wind turbine generator

    NASA Technical Reports Server (NTRS)

    Shepherd, Kevin P.; Hubbard, Harvey H.

    1989-01-01

    Both narrow band and broad band acoustic data were obtained for the MOD5-B wind turbine for a range of wind speeds from 5.8 to 14.3 m/s; for a range of power outputs from 300 to 3100 kW; and for various azimuth angles and distances. Comparisons are made with those of other large machines and with predictions by available methods. The highest levels occur at the lower frequencies and generally decrease as the frequency increases. Low frequency rotational noise components were more intense than expected for an upwind machine and are believed to result from localized wind gradients across the rotor disk due to upwind terrain features. Predicted broad band spectra follow the general trends of the data but tend to underestimate the levels in the frequency range where the turbulent boundary layer-trailing edge interaction noise is expected to be significant.

  9. Fault Diagnosis System of Wind Turbine Generator Based on Petri Net

    NASA Astrophysics Data System (ADS)

    Zhang, Han

    Petri net is an important tool for discrete event dynamic systems modeling and analysis. And it has great ability to handle concurrent phenomena and non-deterministic phenomena. Currently Petri nets used in wind turbine fault diagnosis have not participated in the actual system. This article will combine the existing fuzzy Petri net algorithms; build wind turbine control system simulation based on Siemens S7-1200 PLC, while making matlab gui interface for migration of the system to different platforms.

  10. Operating experience with the 200 kW MOD-OA wind turbine generators

    NASA Technical Reports Server (NTRS)

    Birchenough, A. G.; Saunders, A. L.; Nyland, T. W.; Shaltens, R. K.

    1981-01-01

    The machine configuration and its advantages and disadvantages, particularly as it affects reliability are discussed. The machine performance, both availability and power output characteristics are described. The Mod-OA operational experience is documented. The characteristics of the wind energy generated, the machine performance, and the subsystem strengths and weaknesses are discussed. An assessment of the project success in fulfilling its goals and objectives is also presented.

  11. Operating experience with four 200 kW Mod-0A wind turbine generators

    NASA Technical Reports Server (NTRS)

    Birchenough, A. G.; Saunders, A. L.; Nyland, T. W.; Shaltens, R. K.

    1982-01-01

    The windpowered generator, Mod-0A, and its advantages and disadvantages, particularly as it affects reliability, are discussed. The machine performance with regard to power availability and power output is discussed.

  12. Wind Turbine Generator System Acoustic Noise Test Report for the ARE 442 Wind Turbine

    SciTech Connect

    Huskey, A.; van Dam, J.

    2010-11-01

    This test was conducted on the ARE 442 as part of the U.S. Department of Energy's (DOE's) Independent Testing project. This project was established to help reduce the barriers of wind energy expansion by providing independent testing results for small turbines. In total, five turbines are being tested at the National Wind Technology Center (NWTC) as a part of this project. Acoustic noise testing is one of up to five tests that may be performed on the turbines, including duration, safety and function, power performance, and power quality tests. The acoustic noise test was conducted to the IEC 61400-11 Edition 2.1.

  13. Design and fabrication of composite blades for the Mod-1 wind turbine generator

    NASA Technical Reports Server (NTRS)

    Batesole, W. R.; Gunsallus, C. T.

    1981-01-01

    The design, tooling, fabrication, quality control, and testing phases carried out to date, as well as testing still planned are described. Differences from the 150 foot blade which were introduced for cost and manufacturing improvement purposes are discussed as well as the lightning protection system installed in the blades. Actual costs and manhours expended for Blade No. 2 are provided as a base, along with a projection of costs for the blade in production.

  14. Sound measurements and observations of the MOD-OA wind turbine generator

    NASA Technical Reports Server (NTRS)

    Shepherd, K. P.; Hubbard, H. H.

    1982-01-01

    Sound measurements are reported for a wind velocity of about 5 m/s and a power output of about 70 kW. Both broadband and narrowband data were obtained for a range of distances and azimuth angles from the machine. Both discrete frequency and broadband components were identified. Loading harmonics at multiples of the blade passage frequency and electrical generator harmonics at multiples of the shaft speed dominated the spectrum below 100 Hz. The 10,000 Hz peak is believed to be of mechanical origin in the nacelle and the other arises from blade aerodynamic sources. Aural detection distances of about 525 m upwind and 850 downwind were observed.

  15. Wind turbine generators having wind assisted cooling systems and cooling methods

    DOEpatents

    Bagepalli, Bharat; Barnes, Gary R.; Gadre, Aniruddha D.; Jansen, Patrick L.; Bouchard, Jr., Charles G.; Jarczynski, Emil D.; Garg, Jivtesh

    2008-09-23

    A wind generator includes: a nacelle; a hub carried by the nacelle and including at least a pair of wind turbine blades; and an electricity producing generator including a stator and a rotor carried by the nacelle. The rotor is connected to the hub and rotatable in response to wind acting on the blades to rotate the rotor relative to the stator to generate electricity. A cooling system is carried by the nacelle and includes at least one ambient air inlet port opening through a surface of the nacelle downstream of the hub and blades, and a duct for flowing air from the inlet port in a generally upstream direction toward the hub and in cooling relation to the stator.

  16. Opportunities for ice storage to provide ancillary services to power grids incorporating wind turbine generation

    NASA Astrophysics Data System (ADS)

    Finley, Christopher

    Power generation using wind turbines increases the electrical system balancing, regulation and ramp rate requirements due to the minute to minute variability in wind speed and the difficulty in accurately forecasting wind speeds. The addition of thermal energy storage, such as ice storage, to a building's space cooling equipment increases the operational flexibility of the equipment by allowing the owner to choose when the chiller is run. The ability of the building owner to increase the power demand from the chiller (e.g. make ice) or to decrease the power demand (e.g. melt ice) to provide electrical system ancillary services was evaluated.

  17. Kaman 40 kW wind turbine generator - control system dynamics

    NASA Technical Reports Server (NTRS)

    Perley, R.

    1981-01-01

    The generator design incorporates an induction generator for application where a utility line is present and a synchronous generator for standalone applications. A combination of feed forward and feedback control is used to achieve synchronous speed prior to connecting the generator to the load, and to control the power level once the generator is connected. The dynamics of the drive train affect several aspects of the system operation. These were analyzed to arrive at the required shaft stiffness. The rotor parameters that affect the stability of the feedback control loop vary considerably over the wind speed range encountered. Therefore, the controller gain was made a function of wind speed in order to maintain consistent operation over the whole wind speed range. The velocity requirement for the pitch control mechanism is related to the nature of the wind gusts to be encountered, the dynamics of the system, and the acceptable power fluctuations and generator dropout rate. A model was developed that allows the probable dropout rate to be determined from a statistical model of wind gusts and the various system parameters, including the acceptable power fluctuation.

  18. The application of hydraulics in the 2,000 kW wind turbine generator

    NASA Technical Reports Server (NTRS)

    Onufreiczuk, S.

    1978-01-01

    A 2000 kW turbine generator using hydraulic power in two of its control systems is being built under the management of NASA Lewis Research Center. The hydraulic systems providing the control torques and forces for the yaw and blade pitch control systems are discussed. The yaw-drive-system hydraulic supply provides the power for positioning the nacelle so that the rotary axis is kept in line with the direction of the prevailing wind, as well as pressure to the yaw and high speed shaft brakes. The pitch-change-mechanism hydraulic system provides the actuation to the pitch change mechanism and permits feathering of the blades during an emergency situation. It operates in conjunction with the overall windmill computer system, with the feather control permitting slewing control flow to pass from the servo valve to the actuators without restriction.

  19. Control design for a wind turbine-generator using output feedback

    NASA Technical Reports Server (NTRS)

    Javid, S. H.; Murdoch, A.; Winkelman, J. R.

    1981-01-01

    The modeling and approach to control design for a large horizontal axis wind turbine (WT) generator are presented. The control design is based on a suboptimal output regulator which allows coordinated control of WT blade pitch angle and field voltage for the purposes of regulating electrical power and terminal voltage. Results of detailed non-linear simulation tests of this controller are shown.

  20. Drive Train Normal Modes Analysis for the ERDA/NASA 100-Kilowatt Wind Turbine Generator

    NASA Technical Reports Server (NTRS)

    Sullivan, T. L.; Miller, D. R.; Spera, D. A.

    1977-01-01

    Natural frequencies, as a function of power were determined using a finite element model. Operating conditions investigated were operation with a resistive electrical load and operation synchronized to an electrical utility grid. The influence of certain drive train components on frequencies and mode shapes is shown. An approximate method for obtaining drive train natural frequencies is presented.

  1. Simulation for Wind Turbine Generators -- With FAST and MATLAB-Simulink Modules

    SciTech Connect

    Singh, M.; Muljadi, E.; Jonkman, J.; Gevorgian, V.; Girsang, I.; Dhupia, J.

    2014-04-01

    This report presents the work done to develop generator and gearbox models in the Matrix Laboratory (MATLAB) environment and couple them to the National Renewable Energy Laboratory's Fatigue, Aerodynamics, Structures, and Turbulence (FAST) program. The goal of this project was to interface the superior aerodynamic and mechanical models of FAST to the excellent electrical generator models found in various Simulink libraries and applications. The scope was limited to Type 1, Type 2, and Type 3 generators and fairly basic gear-train models. Future work will include models of Type 4 generators and more-advanced gear-train models with increased degrees of freedom. As described in this study, implementation of the developed drivetrain model enables the software tool to be used in many ways. Several case studies are presented as examples of the many types of studies that can be performed using this tool.

  2. National Renewable Energy Laboratory program on lightning risk and wind turbine generator protection

    SciTech Connect

    Muljadi, E; McNiff, B

    1997-09-01

    This paper will describe the NREL program for addressing lightning protection for wind turbines. A test program will begin this summer at the Central and South West Services Inc. (CSW) wind farm near Fort Davis, Texas, to assess lightning risk, the frequency of lightning strikes on wind turbines compared to risk assessment predictions, and the effectiveness of some protection techniques. A Web page will be assembled to provide resources for designers and operators and feedback for issues as they arise. Also, a database of lightning events (and corresponding damage) will be collected to assist in maturing the understanding of wind turbine lightning protection.

  3. MOD-OA 200 kW wind turbine generator engineeringing

    NASA Technical Reports Server (NTRS)

    Andersen, T. S.; Bodenschatz, C. A.; Eggers, A. G.; Hughes, P. S.; Lampe, R. F.

    1980-01-01

    Engineering drawings and the detailed mechanical and electrical design of a horizontal-axis wind turbine designed for DOE at the NASA Lewis Research Center and installed in Clayton, New Mexico are discussed. The drawings show the hub, pitch change mechanism, drive train, nacelle equipment, yaw drive system, tower, foundation, electrical power systems, and the control and safety systems.

  4. Fiberglass composite blades for the 2 MW Mod-1 wind turbine generator

    NASA Technical Reports Server (NTRS)

    Batesole, W. R.

    1982-01-01

    In mid-1979, NASA contracted with Kaman Aerospace Corporation for the design, manufacture, and ground testing of two 100 foot composite rotor blades intended for operation on the Mod-1 wind turbine. The Mod-1 blades have been completed and are currently stored at the Kaman facility. The design, tooling, fabrication, and testing phases which have been carried out to date, as well as testing still planned are described. Discussed are differences from the 150 foot blade which were introduced for cost and manufacturing improvement purposes. Also included is a description of the lightning protection system installed in the blades, and its development program. Actual costs and manhours expended for Blade No. 2 are provided as a base, along with a projection of costs for the blade in production. Finally, cost drivers are identified relative to future designs.

  5. Wind Turbine Generator System Duration Test Report for the Mariah Power Windspire Wind Turbine

    SciTech Connect

    Huskey, A.; Bowen, A.; Jager, D.

    2010-05-01

    This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project to help reduce the barriers of wind energy expansion by providing independent testing results for small turbines. In total, five turbines are being tested at the National Wind Technology Center (NWTC) as a part of the first round of this project. Duration testing is one of up to five tests that may be performed on the turbines. Other tests include power performance, safety and function, noise, and power quality tests. NWTC testing results provide manufacturers with reports that may be used to meet part of small wind turbine certification requirements. This duration test report focuses on the Mariah Power Windspire wind turbine.

  6. REGIONAL AIR POLLUTION STUDY, EMISSION INVENTORY SUMMARIZATION

    EPA Science Inventory

    As part of the Regional Air Pollution Study (RAPS), data for an air pollution emission inventory are summarized for point and area sources in the St. Louis Air Quality Control Region. Data for point sources were collected for criteria and noncriteria pollutants, hydrocarbons, sul...

  7. Task-Driven Dynamic Text Summarization

    ERIC Educational Resources Information Center

    Workman, Terri Elizabeth

    2011-01-01

    The objective of this work is to examine the efficacy of natural language processing (NLP) in summarizing bibliographic text for multiple purposes. Researchers have noted the accelerating growth of bibliographic databases. Information seekers using traditional information retrieval techniques when searching large bibliographic databases are often…

  8. PROX: Approximated Summarization of Data Provenance

    PubMed Central

    Ainy, Eleanor; Bourhis, Pierre; Davidson, Susan B.; Deutch, Daniel; Milo, Tova

    2016-01-01

    Many modern applications involve collecting large amounts of data from multiple sources, and then aggregating and manipulating it in intricate ways. The complexity of such applications, combined with the size of the collected data, makes it difficult to understand the application logic and how information was derived. Data provenance has been proven helpful in this respect in different contexts; however, maintaining and presenting the full and exact provenance may be infeasible, due to its size and complex structure. For that reason, we introduce the notion of approximated summarized provenance, where we seek a compact representation of the provenance at the possible cost of information loss. Based on this notion, we have developed PROX, a system for the management, presentation and use of data provenance for complex applications. We propose to demonstrate PROX in the context of a movies rating crowd-sourcing system, letting participants view provenance summarization and use it to gain insights on the application and its underlying data. PMID:27570843

  9. HARVEST, a longitudinal patient record summarizer

    PubMed Central

    Hirsch, Jamie S; Tanenbaum, Jessica S; Lipsky Gorman, Sharon; Liu, Connie; Schmitz, Eric; Hashorva, Dritan; Ervits, Artem; Vawdrey, David; Sturm, Marc; Elhadad, Noémie

    2015-01-01

    Objective To describe HARVEST, a novel point-of-care patient summarization and visualization tool, and to conduct a formative evaluation study to assess its effectiveness and gather feedback for iterative improvements. Materials and methods HARVEST is a problem-based, interactive, temporal visualization of longitudinal patient records. Using scalable, distributed natural language processing and problem salience computation, the system extracts content from the patient notes and aggregates and presents information from multiple care settings. Clinical usability was assessed with physician participants using a timed, task-based chart review and questionnaire, with performance differences recorded between conditions (standard data review system and HARVEST). Results HARVEST displays patient information longitudinally using a timeline, a problem cloud as extracted from notes, and focused access to clinical documentation. Despite lack of familiarity with HARVEST, when using a task-based evaluation, performance and time-to-task completion was maintained in patient review scenarios using HARVEST alone or the standard clinical information system at our institution. Subjects reported very high satisfaction with HARVEST and interest in using the system in their daily practice. Discussion HARVEST is available for wide deployment at our institution. Evaluation provided informative feedback and directions for future improvements. Conclusions HARVEST was designed to address the unmet need for clinicians at the point of care, facilitating review of essential patient information. The deployment of HARVEST in our institution allows us to study patient record summarization as an informatics intervention in a real-world setting. It also provides an opportunity to learn how clinicians use the summarizer, enabling informed interface and content iteration and optimization to improve patient care. PMID:25352564

  10. Method for gathering and summarizing internet information

    DOEpatents

    Potok, Thomas E [Oak Ridge, TN; Elmore, Mark Thomas [Oak Ridge, TN; Reed, Joel Wesley [Knoxville, TN; Treadwell, Jim N; Samatova, Nagiza Faridovna [Oak Ridge, TN

    2008-01-01

    A computer method of gathering and summarizing large amounts of information comprises collecting information from a plurality of information sources (14, 51) according to respective maps (52) of the information sources (14), converting the collected information from a storage format to XML-language documents (26, 53) and storing the XML-language documents in a storage medium, searching for documents (55) according to a search query (13) having at least one term and identifying the documents (26) found in the search, and displaying the documents as nodes (33) of a tree structure (32) having links (34) and nodes (33) so as to indicate similarity of the documents to each other.

  11. System for gathering and summarizing internet information

    DOEpatents

    Potok, Thomas E.; Elmore, Mark Thomas; Reed, Joel Wesley; Treadwell, Jim N.; Samatova, Nagiza Faridovna

    2006-07-04

    A computer method of gathering and summarizing large amounts of information comprises collecting information from a plurality of information sources (14, 51) according to respective maps (52) of the information sources (14), converting the collected information from a storage format to XML-language documents (26, 53) and storing the XML-language documents in a storage medium, searching for documents (55) according to a search query (13) having at least one term and identifying the documents (26) found in the search, and displaying the documents as nodes (33) of a tree structure (32) having links (34) and nodes (33) so as to indicate similarity of the documents to each other.

  12. Method for gathering and summarizing internet information

    DOEpatents

    Potok, Thomas E.; Elmore, Mark Thomas; Reed, Joel Wesley; Treadwell, Jim N.; Samatova, Nagiza Faridovna

    2010-04-06

    A computer method of gathering and summarizing large amounts of information comprises collecting information from a plurality of information sources (14, 51) according to respective maps (52) of the information sources (14), converting the collected information from a storage format to XML-language documents (26, 53) and storing the XML-language documents in a storage medium, searching for documents (55) according to a search query (13) having at least one term and identifying the documents (26) found in the search, and displaying the documents as nodes (33) of a tree structure (32) having links (34) and nodes (33) so as to indicate similarity of the documents to each other.

  13. Figure-Associated Text Summarization and Evaluation

    PubMed Central

    Polepalli Ramesh, Balaji; Sethi, Ricky J.; Yu, Hong

    2015-01-01

    Biomedical literature incorporates millions of figures, which are a rich and important knowledge resource for biomedical researchers. Scientists need access to the figures and the knowledge they represent in order to validate research findings and to generate new hypotheses. By themselves, these figures are nearly always incomprehensible to both humans and machines and their associated texts are therefore essential for full comprehension. The associated text of a figure, however, is scattered throughout its full-text article and contains redundant information content. In this paper, we report the continued development and evaluation of several figure summarization systems, the FigSum+ systems, that automatically identify associated texts, remove redundant information, and generate a text summary for every figure in an article. Using a set of 94 annotated figures selected from 19 different journals, we conducted an intrinsic evaluation of FigSum+. We evaluate the performance by precision, recall, F1, and ROUGE scores. The best FigSum+ system is based on an unsupervised method, achieving F1 score of 0.66 and ROUGE-1 score of 0.97. The annotated data is available at figshare.com (http://figshare.com/articles/Figure_Associated_Text_Summarization_and_Evaluation/858903). PMID:25643357

  14. Effective Replays and Summarization of Virtual Experiences

    PubMed Central

    Ponto, Kevin; Kohlmann, Joe; Gleicher, Michael

    2012-01-01

    Direct replays of the experience of a user in a virtual environment are difficult for others to watch due to unnatural camera motions. We present methods for replaying and summarizing these egocentric experiences that effectively communicate the users observations while reducing unwanted camera movements. Our approach summarizes the viewpoint path as a concise sequence of viewpoints that cover the same parts of the scene. The core of our approach is a novel content dependent metric that can be used to identify similarities between viewpoints. This enables viewpoints to be grouped by similar contextual view information and provides a means to generate novel viewpoints that can encapsulate a series of views. These resulting encapsulated viewpoints are used to synthesize new camera paths that convey the content of the original viewers experience. Projecting the initial movement of the user back on the scene can be used to convey the details of their observations, and the extracted viewpoints can serve as bookmarks for control or analysis. Finally we present performance analysis along with two forms of validation to test whether the extracted viewpoints are representative of the viewers original observations and to test for the overall effectiveness of the presented replay methods. PMID:22402688

  15. Figure-associated text summarization and evaluation.

    PubMed

    Polepalli Ramesh, Balaji; Sethi, Ricky J; Yu, Hong

    2015-01-01

    Biomedical literature incorporates millions of figures, which are a rich and important knowledge resource for biomedical researchers. Scientists need access to the figures and the knowledge they represent in order to validate research findings and to generate new hypotheses. By themselves, these figures are nearly always incomprehensible to both humans and machines and their associated texts are therefore essential for full comprehension. The associated text of a figure, however, is scattered throughout its full-text article and contains redundant information content. In this paper, we report the continued development and evaluation of several figure summarization systems, the FigSum+ systems, that automatically identify associated texts, remove redundant information, and generate a text summary for every figure in an article. Using a set of 94 annotated figures selected from 19 different journals, we conducted an intrinsic evaluation of FigSum+. We evaluate the performance by precision, recall, F1, and ROUGE scores. The best FigSum+ system is based on an unsupervised method, achieving F1 score of 0.66 and ROUGE-1 score of 0.97. The annotated data is available at figshare.com (http://figshare.com/articles/Figure_Associated_Text_Summarization_and_Evaluation/858903). PMID:25643357

  16. Effective replays and summarization of virtual experiences.

    PubMed

    Ponto, Kevin; Kohlmann, Joe; Gleicher, Michael

    2012-04-01

    Direct replay of the experience of a user in a virtual environment is difficult for others to watch due to unnatural camera motions. We present methods for replaying and summarizing these egocentric experiences that effectively communicate the user's observations while reducing unwanted camera movements. Our approach summarizes the viewpoint path as a concise sequence of viewpoints that cover the same parts of the scene. The core of our approach is a novel content-dependent metric that can be used to identify similarities between viewpoints. This enables viewpoints to be grouped by similar contextual view information and provides a means to generate novel viewpoints that can encapsulate a series of views. These resulting encapsulated viewpoints are used to synthesize new camera paths that convey the content of the original viewer's experience. Projecting the initial movement of the user back on the scene can be used to convey the details of their observations, and the extracted viewpoints can serve as bookmarks for control or analysis. Finally we present performance analysis along with two forms of validation to test whether the extracted viewpoints are representative of the viewer's original observations and to test for the overall effectiveness of the presented replay methods. PMID:22402688

  17. Summarizing X-ray Stellar Spectra

    NASA Astrophysics Data System (ADS)

    Lee, Hyunsook; Kashyap, V.; XAtlas Collaboration

    2008-05-01

    XAtlas is a spectrum database made with the High Resolution Transmission Grating on the Chandra X-ray Observatory, after painstaking detailed emission measure analysis to extract quantified information. Here, we explore the possibility of summarizing this spectral information into relatively convenient measurable quantities via dimension reduction methods. Principal component analysis, simple component analysis, projection pursuit, independent component analysis, and parallel coordinates are employed to enhance any patterned structures embedded in the high dimensional space. We discuss pros and cons of each dimension reduction method as a part of developing clustering algorithms for XAtlas. The biggest challenge from analyzing XAtlas was handling missing values that pertain astrophysical importance. This research was supported by NASA/AISRP grant NNG06GF17G and NASA contract NAS8-39073.

  18. Algorithm for Video Summarization of Bronchoscopy Procedures

    PubMed Central

    2011-01-01

    Background The duration of bronchoscopy examinations varies considerably depending on the diagnostic and therapeutic procedures used. It can last more than 20 minutes if a complex diagnostic work-up is included. With wide access to videobronchoscopy, the whole procedure can be recorded as a video sequence. Common practice relies on an active attitude of the bronchoscopist who initiates the recording process and usually chooses to archive only selected views and sequences. However, it may be important to record the full bronchoscopy procedure as documentation when liability issues are at stake. Furthermore, an automatic recording of the whole procedure enables the bronchoscopist to focus solely on the performed procedures. Video recordings registered during bronchoscopies include a considerable number of frames of poor quality due to blurry or unfocused images. It seems that such frames are unavoidable due to the relatively tight endobronchial space, rapid movements of the respiratory tract due to breathing or coughing, and secretions which occur commonly in the bronchi, especially in patients suffering from pulmonary disorders. Methods The use of recorded bronchoscopy video sequences for diagnostic, reference and educational purposes could be considerably extended with efficient, flexible summarization algorithms. Thus, the authors developed a prototype system to create shortcuts (called summaries or abstracts) of bronchoscopy video recordings. Such a system, based on models described in previously published papers, employs image analysis methods to exclude frames or sequences of limited diagnostic or education value. Results The algorithm for the selection or exclusion of specific frames or shots from video sequences recorded during bronchoscopy procedures is based on several criteria, including automatic detection of "non-informative", frames showing the branching of the airways and frames including pathological lesions. Conclusions The paper focuses on the

  19. Blind summarization: content-adaptive video summarization using time-series analysis

    NASA Astrophysics Data System (ADS)

    Divakaran, Ajay; Radhakrishnan, Regunathan; Peker, Kadir A.

    2006-01-01

    Severe complexity constraints on consumer electronic devices motivate us to investigate general-purpose video summarization techniques that are able to apply a common hardware setup to multiple content genres. On the other hand, we know that high quality summaries can only be produced with domain-specific processing. In this paper, we present a time-series analysis based video summarization technique that provides a general core to which we are able to add small content-specific extensions for each genre. The proposed time-series analysis technique consists of unsupervised clustering of samples taken through sliding windows from the time series of features obtained from the content. We classify content into two broad categories, scripted content such as news and drama, and unscripted content such as sports and surveillance. The summarization problem then reduces to finding either finding semantic boundaries of the scripted content or detecting highlights in the unscripted content. The proposed technique is essentially an event detection technique and is thus best suited to unscripted content, however, we also find applications to scripted content. We thoroughly examine the trade-off between content-neutral and content-specific processing for effective summarization for a number of genres, and find that our core technique enables us to minimize the complexity of the content-specific processing and to postpone it to the final stage. We achieve the best results with unscripted content such as sports and surveillance video in terms of quality of summaries and minimizing content-specific processing. For other genres such as drama, we find that more content-specific processing is required. We also find that judicious choice of key audio-visual object detectors enables us to minimize the complexity of the content-specific processing while maintaining its applicability to a broad range of genres. We will present a demonstration of our proposed technique at the conference.

  20. Applications of remote sensing to wind power facility siting

    NASA Astrophysics Data System (ADS)

    Wade, J. E.; Rosenfeld, C. L.; Maule, P. A.

    A method by which wind energy prospectors can use remote sensing to rapidly examine extensive geographical areas to identify potential wind turbine generators' sites is outlined. Remote sensing in wind prospecting is not being considered as a tool for determining wind power potential but, rather, as an aid in identifying terrestrial, marine, and atmospheric characteristics associated with desirable wind power sites. It is noted that locations with interesting features noted in a regional assessment can be more closely evaluated using medium-scale imagery, which can be acquired from a number of different agencies, among them the U.S. Forest Service, the Bureau of Land Management, Water and Power Resources and the Soil Conservation Service. Once specific locations have been identified from small- and medium-scale imagery, low-level aerial reconnaissance in a locally chartered aircraft can verify the information obtained. Wind-deformed trees, active slip faces on dunes, snow cornices, snow fences, and the slopes of ridges can be evaluated.

  1. Experience and Assessment of the DOE/NASA Mod-1 2000 Kw Wind Turbine Generator at Boone, North Carolina

    NASA Technical Reports Server (NTRS)

    Collins, J. L.; Shaltens, R. K.; Poor, R. H.; Barton, R. S.

    1982-01-01

    The Mod 1 program objectives are defined. The Mod 1 wind turbine is described. In addition to the steel blade operated on the wind turbine, a composite blade was designed and manufactured. During the early phase of the manufacturing cycle of Mod 1A configuration was designed that identified concepts such as partial span control, a soft tower, and upwind teetered rotors that were incorporated in second and third generation industry designs. The Mod 1 electrical system performed as designed, with voltage flicker characteristics within acceptable utility limits.

  2. Wind turbine generator interaction with conventional diesel generators on Block Island, Rhode Island. Volume 2: Data analysis

    NASA Technical Reports Server (NTRS)

    Wilreker, V. F.; Stiller, P. H.; Scott, G. W.; Kruse, V. J.; Smith, R. F.

    1984-01-01

    Assessing the performance of a MOD-OA horizontal axis wind turbine connected to an isolated diesel utility, a comprehensive data measurement program was conducted on the Block Island Power Company installation on Block Island, Rhode Island. The detailed results of that program focusing on three principal areas of (1) fuel displacement (savings), (2) dynamic interaction between the diesel utility and the wind turbine, (3) effects of three models of wind turbine reactive power control are presented. The approximate two month duration of the data acquisition program conducted in the winter months (February into April 1982) revealed performance during periods of highest wind energy penetration and hence severity of operation. Even under such conditions fuel savings were significant resulting in a fuel reduction of 6.7% while the MOD-OA was generating 10.7% of the total electrical energy. Also, electrical disturbance and interactive effects were of an acceptable level.

  3. Wind turbine/generator set having a stator cooling system located between stator frame and active coils

    DOEpatents

    Bevington, Christopher M.; Bywaters, Garrett L.; Coleman, Clint C.; Costin, Daniel P.; Danforth, William L.; Lynch, Jonathan A.; Rolland, Robert H.

    2012-11-13

    A wind turbine comprising an electrical generator that includes a rotor assembly. A wind rotor that includes a wind rotor hub is directly coupled to the rotor assembly via a simplified connection. The wind rotor and generator rotor assembly are rotatably mounted on a central spindle via a bearing assembly. The wind rotor hub includes an opening having a diameter larger than the outside diameter of the central spindle adjacent the bearing assembly so as to allow access to the bearing assembly from a cavity inside the wind rotor hub. The spindle is attached to a turret supported by a tower. Each of the spindle, turret and tower has an interior cavity that permits personnel to traverse therethrough to the cavity of the wind rotor hub. The wind turbine further includes a frictional braking system for slowing, stopping or keeping stopped the rotation of the wind rotor and rotor assembly.

  4. Wind Turbine Generator System Power Quality Test Report for the Gaia Wind 11-kW Wind Turbine

    SciTech Connect

    Curtis, A.; Gevorgian, V.

    2011-07-01

    This report details the power quality test on the Gaia Wind 11-kW Wind Turbine as part of the U.S. Department of Energy's Independent Testing Project. In total five turbines are being tested as part of the project. Power quality testing is one of up to five test that may be performed on the turbines including power performance, safety and function, noise, and duration tests. The results of the testing provide manufacturers with reports that may be used for small wind turbine certification.

  5. The Use of Summarization Tasks: Some Lexical and Conceptual Analyses

    ERIC Educational Resources Information Center

    Yu, Guoxing

    2013-01-01

    This article reports the lexical diversity of summaries written by experts and test takers in an empirical study and then interrogates the (in)congruity between the conceptualisations of "summary" and "summarize" in the literature of educational research and the operationalization of summarization tasks in three international English language…

  6. On the Application of Generic Summarization Algorithms to Music

    NASA Astrophysics Data System (ADS)

    Raposo, Francisco; Ribeiro, Ricardo; de Matos, David Martins

    2015-01-01

    Several generic summarization algorithms were developed in the past and successfully applied in fields such as text and speech summarization. In this paper, we review and apply these algorithms to music. To evaluate this summarization's performance, we adopt an extrinsic approach: we compare a Fado Genre Classifier's performance using truncated contiguous clips against the summaries extracted with those algorithms on 2 different datasets. We show that Maximal Marginal Relevance (MMR), LexRank and Latent Semantic Analysis (LSA) all improve classification performance in both datasets used for testing.

  7. Extractive summarization using complex networks and syntactic dependency

    NASA Astrophysics Data System (ADS)

    Amancio, Diego R.; Nunes, Maria G. V.; Oliveira, Osvaldo N.; Costa, Luciano da F.

    2012-02-01

    The realization that statistical physics methods can be applied to analyze written texts represented as complex networks has led to several developments in natural language processing, including automatic summarization and evaluation of machine translation. Most importantly, so far only a few metrics of complex networks have been used and therefore there is ample opportunity to enhance the statistics-based methods as new measures of network topology and dynamics are created. In this paper, we employ for the first time the metrics betweenness, vulnerability and diversity to analyze written texts in Brazilian Portuguese. Using strategies based on diversity metrics, a better performance in automatic summarization is achieved in comparison to previous work employing complex networks. With an optimized method the Rouge score (an automatic evaluation method used in summarization) was 0.5089, which is the best value ever achieved for an extractive summarizer with statistical methods based on complex networks for Brazilian Portuguese. Furthermore, the diversity metric can detect keywords with high precision, which is why we believe it is suitable to produce good summaries. It is also shown that incorporating linguistic knowledge through a syntactic parser does enhance the performance of the automatic summarizers, as expected, but the increase in the Rouge score is only minor. These results reinforce the suitability of complex network methods for improving automatic summarizers in particular, and treating text in general.

  8. Summarization of Text Document Using Query Dependent Parsing Techniques

    NASA Astrophysics Data System (ADS)

    Rokade, P. P.; Mrunal, Bewoor; Patil, S. H.

    2010-11-01

    World Wide Web is the largest source of information. Huge amount of data is present on the Web. There has been a great amount of work on query-independent summarization of documents. However, due to the success of Web search engines query-specific document summarization (query result snippets) has become an important problem. In this paper a method to create query specific summaries by identifying the most query-relevant fragments and combining them using the semantic associations within the document is discussed. In particular, first a structure is added to the documents in the preprocessing stage and converts them to document graphs. The present research work focuses on analytical study of different document clustering and summarization techniques currently the most research is focused on Query-Independent summarization. The main aim of this research work is to combine the both approaches of document clustering and query dependent summarization. This mainly includes applying different clustering algorithms on a text document. Create a weighted document graph of the resulting graph based on the keywords. And obtain the document graph to get the summary of the document. The performance of the summary using different clustering techniques will be analyzed and the optimal approach will be suggested.

  9. Cognitive analysis of the summarization of longitudinal patient records.

    PubMed

    Reichert, Daniel; Kaufman, David; Bloxham, Benjamin; Chase, Herbert; Elhadad, Noémie

    2010-01-01

    Electronic health records contain an abundance of valuable information that can be used to guide patient care. However, the large volume of information embodied in these records also renders access to relevant information a time-consuming and inefficient process. Our ultimate objective is to develop an automated summarizer that succinctly captures all relevant information in the patient record. In this paper, we present a cognitive study of 8 clinicians who were asked to create summaries based on data contained in the patients' electronic health record. The study characterized the primary sources of information that were prioritized by clinicians, the temporal strategies used to develop a summary and the cognitive operations used to guide the summarization process. Although we would not expect the automated summarizer to emulate human performance, we anticipate that this study will inform its development in instrumental ways. PMID:21347062

  10. Adaptive Maximum Marginal Relevance Based Multi-email Summarization

    NASA Astrophysics Data System (ADS)

    Wang, Baoxun; Liu, Bingquan; Sun, Chengjie; Wang, Xiaolong; Li, Bo

    By analyzing the inherent relationship between the maximum marginal relevance (MMR) model and the content cohesion of emails with the same subject, this paper presents an adaptive maximum marginal relevance based multi-email summarization method. Due to the adoption of approximate computing of email content cohesion, the adaptive MMR is able to automatically adjust the parameters according to the changing of the email sets. The experimental results have shown that the email summarizing system based on this technique can increase the precision while reducing the redundancy of the automatic summary results, consequently improve the average quality of email summaries.

  11. Video Analytics for Indexing, Summarization and Searching of Video Archives

    SciTech Connect

    Trease, Harold E.; Trease, Lynn L.

    2009-08-01

    This paper will be submitted to the proceedings The Eleventh IASTED International Conference on. Signal and Image Processing. Given a video or video archive how does one effectively and quickly summarize, classify, and search the information contained within the data? This paper addresses these issues by describing a process for the automated generation of a table-of-contents and keyword, topic-based index tables that can be used to catalogue, summarize, and search large amounts of video data. Having the ability to index and search the information contained within the videos, beyond just metadata tags, provides a mechanism to extract and identify "useful" content from image and video data.

  12. Enhancing Biomedical Text Summarization Using Semantic Relation Extraction

    PubMed Central

    Shang, Yue; Li, Yanpeng; Lin, Hongfei; Yang, Zhihao

    2011-01-01

    Automatic text summarization for a biomedical concept can help researchers to get the key points of a certain topic from large amount of biomedical literature efficiently. In this paper, we present a method for generating text summary for a given biomedical concept, e.g., H1N1 disease, from multiple documents based on semantic relation extraction. Our approach includes three stages: 1) We extract semantic relations in each sentence using the semantic knowledge representation tool SemRep. 2) We develop a relation-level retrieval method to select the relations most relevant to each query concept and visualize them in a graphic representation. 3) For relations in the relevant set, we extract informative sentences that can interpret them from the document collection to generate text summary using an information retrieval based method. Our major focus in this work is to investigate the contribution of semantic relation extraction to the task of biomedical text summarization. The experimental results on summarization for a set of diseases show that the introduction of semantic knowledge improves the performance and our results are better than the MEAD system, a well-known tool for text summarization. PMID:21887336

  13. Investigation of Learners' Perceptions for Video Summarization and Recommendation

    ERIC Educational Resources Information Center

    Yang, Jie Chi; Chen, Sherry Y.

    2012-01-01

    Recently, multimedia-based learning is widespread in educational settings. A number of studies investigate how to develop effective techniques to manage a huge volume of video sources, such as summarization and recommendation. However, few studies examine how these techniques affect learners' perceptions in multimedia learning systems. This…

  14. MPEG content summarization based on compressed domain feature analysis

    NASA Astrophysics Data System (ADS)

    Sugano, Masaru; Nakajima, Yasuyuki; Yanagihara, Hiromasa

    2003-11-01

    This paper addresses automatic summarization of MPEG audiovisual content on compressed domain. By analyzing semantically important low-level and mid-level audiovisual features, our method universally summarizes the MPEG-1/-2 contents in the form of digest or highlight. The former is a shortened version of an original, while the latter is an aggregation of important or interesting events. In our proposal, first, the incoming MPEG stream is segmented into shots and the above features are derived from each shot. Then the features are adaptively evaluated in an integrated manner, and finally the qualified shots are aggregated into a summary. Since all the processes are performed completely on compressed domain, summarization is achieved at very low computational cost. The experimental results show that news highlights and sports highlights in TV baseball games can be successfully extracted according to simple shot transition models. As for digest extraction, subjective evaluation proves that meaningful shots are extracted from content without a priori knowledge, even if it contains multiple genres of programs. Our method also has the advantage of generating an MPEG-7 based description such as summary and audiovisual segments in the course of summarization.

  15. Gaze-enabled Egocentric Video Summarization via Constrained Submodular Maximization

    PubMed Central

    Xut, Jia; Mukherjee, Lopamudra; Li, Yin; Warner, Jamieson; Rehg, James M.; Singht, Vikas

    2016-01-01

    With the proliferation of wearable cameras, the number of videos of users documenting their personal lives using such devices is rapidly increasing. Since such videos may span hours, there is an important need for mechanisms that represent the information content in a compact form (i.e., shorter videos which are more easily browsable/sharable). Motivated by these applications, this paper focuses on the problem of egocentric video summarization. Such videos are usually continuous with significant camera shake and other quality issues. Because of these reasons, there is growing consensus that direct application of standard video summarization tools to such data yields unsatisfactory performance. In this paper, we demonstrate that using gaze tracking information (such as fixation and saccade) significantly helps the summarization task. It allows meaningful comparison of different image frames and enables deriving personalized summaries (gaze provides a sense of the camera wearer's intent). We formulate a summarization model which captures common-sense properties of a good summary, and show that it can be solved as a submodular function maximization with partition matroid constraints, opening the door to a rich body of work from combinatorial optimization. We evaluate our approach on a new gaze-enabled egocentric video dataset (over 15 hours), which will be a valuable standalone resource. PMID:26973428

  16. A Summarization System for Chinese News from Multiple Sources.

    ERIC Educational Resources Information Center

    Chen, Hsin-Hsi; Kuo, June-Jei; Huang, Sheng-Jie; Lin, Chuan-Jie; Wung, Hung-Chia

    2003-01-01

    Proposes a summarization system for multiple documents that employs named entities and other signatures to cluster news from different sources, as well as punctuation marks, linking elements, and topic chains to identify the meaningful units (MUs). Using nouns and verbs to identify similar MUs, focusing and browsing models are applied to represent…

  17. Upper-Intermediate-Level ESL Students' Summarizing in English

    ERIC Educational Resources Information Center

    Vorobel, Oksana; Kim, Deoksoon

    2011-01-01

    This qualitative instrumental case study explores various factors that might influence upper-intermediate-level English as a second language (ESL) students' summarizing from a sociocultural perspective. The study was conducted in a formal classroom setting, during a reading and writing class in the English Language Institute at a university in the…

  18. QCS: a system for querying, clustering and summarizing documents.

    SciTech Connect

    Dunlavy, Daniel M.; Schlesinger, Judith D. (Center for Computing Sciences, Bowie, MD); O'Leary, Dianne P.; Conroy, John M.

    2006-10-01

    Information retrieval systems consist of many complicated components. Research and development of such systems is often hampered by the difficulty in evaluating how each particular component would behave across multiple systems. We present a novel hybrid information retrieval system--the Query, Cluster, Summarize (QCS) system--which is portable, modular, and permits experimentation with different instantiations of each of the constituent text analysis components. Most importantly, the combination of the three types of components in the QCS design improves retrievals by providing users more focused information organized by topic. We demonstrate the improved performance by a series of experiments using standard test sets from the Document Understanding Conferences (DUC) along with the best known automatic metric for summarization system evaluation, ROUGE. Although the DUC data and evaluations were originally designed to test multidocument summarization, we developed a framework to extend it to the task of evaluation for each of the three components: query, clustering, and summarization. Under this framework, we then demonstrate that the QCS system (end-to-end) achieves performance as good as or better than the best summarization engines. Given a query, QCS retrieves relevant documents, separates the retrieved documents into topic clusters, and creates a single summary for each cluster. In the current implementation, Latent Semantic Indexing is used for retrieval, generalized spherical k-means is used for the document clustering, and a method coupling sentence 'trimming', and a hidden Markov model, followed by a pivoted QR decomposition, is used to create a single extract summary for each cluster. The user interface is designed to provide access to detailed information in a compact and useful format. Our system demonstrates the feasibility of assembling an effective IR system from existing software libraries, the usefulness of the modularity of the design, and the

  19. QCS : a system for querying, clustering, and summarizing documents.

    SciTech Connect

    Dunlavy, Daniel M.

    2006-08-01

    Information retrieval systems consist of many complicated components. Research and development of such systems is often hampered by the difficulty in evaluating how each particular component would behave across multiple systems. We present a novel hybrid information retrieval system--the Query, Cluster, Summarize (QCS) system--which is portable, modular, and permits experimentation with different instantiations of each of the constituent text analysis components. Most importantly, the combination of the three types of components in the QCS design improves retrievals by providing users more focused information organized by topic. We demonstrate the improved performance by a series of experiments using standard test sets from the Document Understanding Conferences (DUC) along with the best known automatic metric for summarization system evaluation, ROUGE. Although the DUC data and evaluations were originally designed to test multidocument summarization, we developed a framework to extend it to the task of evaluation for each of the three components: query, clustering, and summarization. Under this framework, we then demonstrate that the QCS system (end-to-end) achieves performance as good as or better than the best summarization engines. Given a query, QCS retrieves relevant documents, separates the retrieved documents into topic clusters, and creates a single summary for each cluster. In the current implementation, Latent Semantic Indexing is used for retrieval, generalized spherical k-means is used for the document clustering, and a method coupling sentence ''trimming'', and a hidden Markov model, followed by a pivoted QR decomposition, is used to create a single extract summary for each cluster. The user interface is designed to provide access to detailed information in a compact and useful format. Our system demonstrates the feasibility of assembling an effective IR system from existing software libraries, the usefulness of the modularity of the design, and the

  20. Medical textbook summarization and guided navigation using statistical sentence extraction.

    PubMed

    Whalen, Gregory

    2005-01-01

    We present a method for automated medical textbook and encyclopedia summarization. Using statistical sentence extraction and semantic relationships, we extract sentences from text returned as part of an existing textbook search (similar to a book index). Our system guides users to the information they desire by summarizing the content of each relevant chapter or section returned in the search. The summary is tailored to contain sentences that specifically address the user's search terms. Our clustering method selects sentences that contain concepts specifically addressing the context of the query term in each of the returned sections. Our method examines conceptual relationships from the UMLS and selects clusters of concepts using Expectation Maximization (EM). Sentences associated with the concept clusters are shown to the user. We evaluated whether our extracted summary provides a suitable answer to the user's question. PMID:16779153

  1. Facilitating physicians' access to information via tailored text summarization.

    PubMed

    Elhadad, Noemie; McKeown, Kathleen; Kaufman, David; Jordan, Desmond

    2005-01-01

    We have developed a summarization system, TAS (Technical Article Summarizer), which, when provided with a patient record and journal articles returned by a search, automatically generates a summary that is tailored to the patient characteristics. We hypothesize that a personalized summary will allow a physician to more quickly find information relevant to patient care. In this paper, we present a user study in which subjects carried out a task under three different conditions: using search results only, using a generic summary and search results, and using a personalized summary with search results. Our study demonstrates that subjects do a better job on task completion with the personalized summary, and show a higher level of satisfaction, than under other conditions. PMID:16779035

  2. Highlight summarization in golf videos using audio signals

    NASA Astrophysics Data System (ADS)

    Kim, Hyoung-Gook; Kim, Jin Young

    2008-01-01

    In this paper, we present an automatic summarization of highlights in golf videos based on audio information alone without video information. The proposed highlight summarization system is carried out based on semantic audio segmentation and detection on action units from audio signals. Studio speech, field speech, music, and applause are segmented by means of sound classification. Swing is detected by the methods of impulse onset detection. Sounds like swing and applause form a complete action unit, while studio speech and music parts are used to anchor the program structure. With the advantage of highly precise detection of applause, highlights are extracted effectively. Our experimental results obtain high classification precision on 18 golf games. It proves that the proposed system is very effective and computationally efficient to apply the technology to embedded consumer electronic devices.

  3. Degree centrality for semantic abstraction summarization of therapeutic studies

    PubMed Central

    Zhang, Han; Fiszman, Marcelo; Shin, Dongwook; Miller, Christopher M.; Rosemblat, Graciela; Rindflesch, Thomas C.

    2011-01-01

    Automatic summarization has been proposed to help manage the results of biomedical information retrieval systems. Semantic MEDLINE, for example, summarizes semantic predications representing assertions in MEDLINE citations. Results are presented as a graph which maintains links to the original citations. Graphs summarizing more than 500 citations are hard to read and navigate, however. We exploit graph theory for focusing these large graphs. The method is based on degree centrality, which measures connectedness in a graph. Four categories of clinical concepts related to treatment of disease were identified and presented as a summary of input text. A baseline was created using term frequency of occurrence. The system was evaluated on summaries for treatment of five diseases compared to a reference standard produced manually by two physicians. The results showed that recall for system results was 72%, precision was 73%, and F-score was 0.72. The system F-score was considerably higher than that for the baseline (0.47). PMID:21575741

  4. An agglomerative approach for shot summarization based on content homogeneity

    NASA Astrophysics Data System (ADS)

    Ioannidis, Antonis; Chasanis, Vasileios; Likas, Aristidis

    2015-02-01

    An efficient shot summarization method is presented based on agglomerative clustering of the shot frames. Unlike other agglomerative methods, our approach relies on a cluster merging criterion that computes the content homogeneity of a merged cluster. An important feature of the proposed approach is the automatic estimation of the number of a shot's most representative frames, called keyframes. The method starts by splitting each video sequence into small, equal sized clusters (segments). Then, agglomerative clustering is performed, where from the current set of clusters, a pair of clusters is selected and merged to form a larger unimodal (homogeneous) cluster. The algorithm proceeds until no further cluster merging is possible. At the end, the medoid of each of the final clusters is selected as keyframe and the set of keyframes constitutes the summary of the shot. Numerical experiments demonstrate that our method reasonable estimates the number of ground-truth keyframes, while extracting non-repetitive keyframes that efficiently summarize the content of each shot.

  5. An unsupervised method for summarizing egocentric sport videos

    NASA Astrophysics Data System (ADS)

    Habibi Aghdam, Hamed; Jahani Heravi, Elnaz; Puig, Domenec

    2015-12-01

    People are getting more interested to record their sport activities using head-worn or hand-held cameras. This type of videos which is called egocentric sport videos has different motion and appearance patterns compared with life-logging videos. While a life-logging video can be defined in terms of well-defined human-object interactions, notwithstanding, it is not trivial to describe egocentric sport videos using well-defined activities. For this reason, summarizing egocentric sport videos based on human-object interaction might fail to produce meaningful results. In this paper, we propose an unsupervised method for summarizing egocentric videos by identifying the key-frames of the video. Our method utilizes both appearance and motion information and it automatically finds the number of the key-frames. Our blind user study on the new dataset collected from YouTube shows that in 93:5% cases, the users choose the proposed method as their first video summary choice. In addition, our method is within the top 2 choices of the users in 99% of studies.

  6. A Graph Summarization Algorithm Based on RFID Logistics

    NASA Astrophysics Data System (ADS)

    Sun, Yan; Hu, Kongfa; Lu, Zhipeng; Zhao, Li; Chen, Ling

    Radio Frequency Identification (RFID) applications are set to play an essential role in object tracking and supply chain management systems. The volume of data generated by a typical RFID application will be enormous as each item will generate a complete history of all the individual locations that it occupied at every point in time. The movement trails of such RFID data form gigantic commodity flowgraph representing the locations and durations of the path stages traversed by each item. In this paper, we use graph to construct a warehouse of RFID commodity flows, and introduce a database-style operation to summarize graphs, which produces a summary graph by grouping nodes based on user-selected node attributes, further allows users to control the hierarchy of summaries. It can cut down the size of graphs, and provide convenience for users to study just on the shrunk graph which they interested. Through extensive experiments, we demonstrate the effectiveness and efficiency of the proposed method.

  7. Disease Related Knowledge Summarization Based on Deep Graph Search

    PubMed Central

    Wu, Xiaofang; Yang, Zhihao; Li, ZhiHeng; Lin, Hongfei; Wang, Jian

    2015-01-01

    The volume of published biomedical literature on disease related knowledge is expanding rapidly. Traditional information retrieval (IR) techniques, when applied to large databases such as PubMed, often return large, unmanageable lists of citations that do not fulfill the searcher's information needs. In this paper, we present an approach to automatically construct disease related knowledge summarization from biomedical literature. In this approach, firstly Kullback-Leibler Divergence combined with mutual information metric is used to extract disease salient information. Then deep search based on depth first search (DFS) is applied to find hidden (indirect) relations between biomedical entities. Finally random walk algorithm is exploited to filter out the weak relations. The experimental results show that our approach achieves a precision of 60% and a recall of 61% on salient information extraction for Carcinoma of bladder and outperforms the method of Combo. PMID:26413521

  8. Invite, listen, and summarize: a patient-centered communication technique.

    PubMed

    Boyle, Dennis; Dwinnell, Brian; Platt, Frederic

    2005-01-01

    The need for physicians to have patient-centered communication skills is reflected in the educational objectives of numerous medical schools' curricula and in the competencies required by groups such as the Accreditation Council for Graduate Medical Education. An innovative method for teaching communications skills has been developed at the University of Colorado School of Medicine as part of its three-year, longitudinal course focusing on basic clinical skills required of all physicians. The method emphasizes techniques of open-ended inquiry, empathy, and engagement to gather data. Students refer to the method as ILS, or Invite, Listen, and Summarize. ILS was developed to combat the high-physician-control interview techniques, characterized by a series of "yes" or "no" questions. The authors began teaching the ILS approach in 2001 as one basic exercise and have since developed a two-year longitudinal communications curriculum. ILS is easy to use and remember, and it emphasizes techniques that have been shown in other studies to achieve the three basic functions of the medical interview: creating rapport, collecting good data, and improving compliance. The skills are taught using standardized patients in a series of four small-group exercises. Videotaped standardized patient encounters are used to evaluate the students. Tutors come from a variety of disciplines and receive standardized training. The curriculum has been well received. Despite the fact that the formal curriculum only occurs in the first two years, there is some evidence that it is improving students' interviewing skills at the end of their third year. PMID:15618088

  9. Applying Semantics in Dataset Summarization for Solar Data Ingest Pipelines

    NASA Astrophysics Data System (ADS)

    Michaelis, J.; McGuinness, D. L.; Zednik, S.; West, P.; Fox, P. A.

    2012-12-01

    for supporting the following use cases: (i) Temporal alignment of time-stamped MLSO observations with raw data gathered at MLSO. (ii) Linking of multiple visualization entries to common (and structurally complex) workflow structures - designed to capture the visualization generation process. To provide real-world use cases for the described approach, a semantic summarization system is being developed for data gathered from HAO's Coronal Multi-channel Polarimeter (CoMP) and Chromospheric Helium-I Imaging Photometer (CHIP) pipelines. Web Links: [1] http://mlso.hao.ucar.edu/ [2] http://www.w3.org/TR/vocab-data-cube/

  10. Effects of Teacher-Directed and Student-Interactive Summarization Instruction on Reading Comprehension and Written Summarization of Korean Fourth Graders

    ERIC Educational Resources Information Center

    Jeong, Jongseong

    2009-01-01

    The purpose of this study was to investigate how Korean fourth graders' performance on reading comprehension and written summarization changes as a function of instruction in summarization across test times. Seventy five Korean fourth graders from three classes were randomly assigned to the collaborative summarization, direct instruction, and…

  11. Rare-Earth-Free Permanent Magnets for Electrical Vehicle Motors and Wind Turbine Generators: Hexagonal Symmetry Based Materials Systems Mn-Bi and M-type Hexaferrite

    SciTech Connect

    Hong, Yang-Ki; Haskew, Timothy; Myryasov, Oleg; Jin, Sungho; Berkowitz, Ami

    2014-06-05

    The research we conducted focuses on the rare-earth (RE)-free permanent magnet by modeling, simulating, and synthesizing exchange coupled two-phase (hard/soft) RE-free core-shell nano-structured magnet. The RE-free magnets are made of magnetically hard core materials (high anisotropy materials including Mn-Bi-X and M-type hexaferrite) coated by soft shell materials (high magnetization materials including Fe-Co or Co). Therefore, our research helps understand the exchange coupling conditions of the core/shell magnets, interface exchange behavior between core and shell materials, formation mechanism of core/shell structures, stability conditions of core and shell materials, etc.

  12. Improvement of AEP Predictions Using Diurnal CFD Modelling with Site-Specific Stability Weightings Provided from Mesoscale Simulation

    NASA Astrophysics Data System (ADS)

    Hristov, Y.; Oxley, G.; Žagar, M.

    2014-06-01

    The Bolund measurement campaign, performed by Danish Technical University (DTU) Wind Energy Department (also known as RISØ), provided significant insight into wind flow modeling over complex terrain. In the blind comparison study several modelling solutions were submitted with the vast majority being steady-state Computational Fluid Dynamics (CFD) approaches with two equation k-epsilon turbulence closure. This approach yielded the most accurate results, and was identified as the state-of-the-art tool for wind turbine generator (WTG) micro-siting. Based on the findings from Bolund, further comparison between CFD and field measurement data has been deemed essential in order to improve simulation accuracy for turbine load and long-term Annual Energy Production (AEP) estimations. Vestas Wind Systems A/S is a major WTG original equipment manufacturer (OEM) with an installed base of over 60GW in over 70 countries accounting for 19% of the global installed base. The Vestas Performance and Diagnostic Centre (VPDC) provides online live data to more than 47GW of these turbines allowing a comprehensive comparison between modelled and real-world energy production data. In previous studies, multiple sites have been simulated with a steady neutral CFD formulation for the atmospheric surface layer (ASL), and wind resource (RSF) files have been generated as a base for long-term AEP predictions showing significant improvement over predictions performed with the industry standard linear WAsP tool. In this study, further improvements to the wind resource file generation with CFD are examined using an unsteady diurnal cycle approach with a full atmospheric boundary layer (ABL) formulation, with the unique stratifications throughout the cycle weighted according to mesoscale simulated sectorwise stability frequencies.

  13. A Study of Cognitive Mapping as a Means to Improve Summarization and Comprehension of Expository Text.

    ERIC Educational Resources Information Center

    Ruddell, Robert B.; Boyle, Owen F.

    1989-01-01

    Investigates the effects of cognitive mapping on written summarization and comprehension of expository text. Concludes that mapping appears to assist students in: (1) developing procedural knowledge resulting in more effective written summarization and (2) identifying and using supporting details in their essays. (MG)

  14. Text Summarization in the Biomedical Domain: A Systematic Review of Recent Research

    PubMed Central

    Mishra, Rashmi; Bian, Jiantao; Fiszman, Marcelo; Weir, Charlene R.; Jonnalagadda, Siddhartha; Mostafa, Javed; Fiol, Guilherme Del

    2014-01-01

    Objective The amount of information for clinicians and clinical researchers is growing exponentially. Text summarization reduces information as an attempt to enable users to find and understand relevant source texts more quickly and effortlessly. In recent years, substantial research has been conducted to develop and evaluate various summarization techniques in the biomedical domain. The goal of this study was to systematically review recent published research on summarization of textual documents in the biomedical domain. Materials and methods MEDLINE (2000 to October 2013), IEEE Digital Library, and the ACM Digital library were searched. Investigators independently screened and abstracted studies that examined text summarization techniques in the biomedical domain. Information is derived from selected articles on five dimensions: input, purpose, output, method and evaluation. Results Of 10,786 studies retrieved, 34 (0.3%) met the inclusion criteria. Natural Language processing (17; 50%) and a Hybrid technique comprising of statistical, Natural language processing and machine learning (15; 44%) were the most common summarization approaches. Most studies (28; 82%) conducted an intrinsic evaluation. Discussion This is the first systematic review of text summarization in the biomedical domain. The study identified research gaps and provides recommendations for guiding future research on biomedical text summarization. conclusion Recent research has focused on a Hybrid technique comprising statistical, language processing and machine learning techniques. Further research is needed on the application and evaluation of text summarization in real research or patient care settings. PMID:25016293

  15. PERSIVAL, a System for Personalized Search and Summarization over Multimedia Healthcare Information.

    ERIC Educational Resources Information Center

    McKeown, Kathleen R.; Chang, Shih-Fu; Cimino, James; Feiner, Steven K.; Friedman, Carol; Gravano, Luis; Hatzivassiloglou, Vasileios; Johnson, Steven; Jordan, Desmond A.; Klavans, Judith L.; Kushniruk, Andre; Patel, Vimla; Teufel, Simone

    This paper reports on the ongoing development of PERSIVAL (Personalized Retrieval and Summarization of Image, Video, and Language), a system designed to provide personalized access to a distributed digital library of medical literature and consumer health information. The goal for PERSIVAL is to tailor search, presentation, and summarization of…

  16. [Briefly summarized nursing card for patients with advanced cancer receiving out hospital management].

    PubMed

    Hayashi, Y; Andoh, M; Hioki, M; Sugitoh, Y; Hyoudoh, C

    1994-12-01

    Briefly summarized nursing card to perform adequate nursing for readmission patients with advanced cancer receiving outhospital management was developed and its clinical usefulness for nursing is discussed. The card is 18 cm x 13 cm, differential colored for diseases, and written only necessary summarized informations for adequate nursing at the patient's emergent readmission. By using this card for 24 patients, it was very useful because of its very selected, brief and summarized information. This card has much usefulness for nursing of such patients. PMID:7802460

  17. More than a "Basic Skill": Breaking down the Complexities of Summarizing for ABE/ESL Learners

    ERIC Educational Resources Information Center

    Ouellette-Schramm, Jennifer

    2015-01-01

    This article describes the complex cognitive and linguistic challenges of summarizing expository text at vocabulary, syntactic, and rhetorical levels. It then outlines activities to help ABE/ESL learners develop corresponding skills.

  18. Clearing the Air: Summarizing the Smoking-related Relative Risks of Bladder and Kidney Cancer.

    PubMed

    Purdue, Mark P; Silverman, Debra T

    2016-09-01

    This Platinum Priority editorial discusses the strengths and limitations of a recent meta-analysis summarizing the published smoking-related relative risks for bladder cancer and kidney cancer. PMID:27130147

  19. Duration Test Report for the Entegrity EW50 Wind Turbine

    SciTech Connect

    Smith, J.; Huskey, A.; Jager, D.; Hur, J.

    2012-12-01

    This report summarizes the results of a duration test that NREL conducted on the Entegrity EW50 wind turbine. This test was conducted in accordance with the International Electrotechnical Commissions' (IEC) standard, Wind Turbine Generator System Part 2: Design requirements for small wind turbines, IEC 61400-2 Ed.2.0, 2006-03.

  20. Evaluating the use of different positional strategies for sentence selection in biomedical literature summarization

    PubMed Central

    2013-01-01

    Background The position of a sentence in a document has been traditionally considered an indicator of the relevance of the sentence, and therefore it is frequently used by automatic summarization systems as an attribute for sentence selection. Sentences close to the beginning of the document are supposed to deal with the main topic and thus are selected for the summary. This criterion has shown to be very effective when summarizing some types of documents, such as news items. However, this property is not likely to be found in other types of documents, such as scientific articles, where other positional criteria may be preferred. The purpose of the present work is to study the utility of different positional strategies for biomedical literature summarization. Results We have evaluated three different positional strategies: (1) awarding the sentences at the beginning of the document, (2) preferring those at the beginning and end of the document, and (3) weighting the sentences according to the section in which they appear. To this end, we have implemented two summarizers, one based on semantic graphs and the other based on concept frequencies, and evaluated the summaries they produce when combined with each of the positional strategies above using ROUGE metrics. Our results indicate that it is possible to improve the quality of the summaries by weighting the sentences according to the section in which they appear (≈17% improvement in ROUGE-2 for the graph-based summarizer and ≈20% for the frequency-based summarizer), and that the sections containing the more salient information are the Methods and Material and the Discussion and Results ones. Conclusions It has been found that the use of traditional positional criteria that award sentences at the beginning and/or the end of the document are not helpful when summarizing scientific literature. In contrast, a more appropriate strategy is that which weights sentences according to the section in which they appear

  1. Theory and implementation of summarization: Improving sensor interpretation for spacecraft operations

    NASA Astrophysics Data System (ADS)

    Swartwout, Michael Alden

    New paradigms in space missions require radical changes in spacecraft operations. In the past, operations were insulated from competitive pressures of cost, quality and time by system infrastructures, technological limitations and historical precedent. However, modern demands now require that operations meet competitive performance goals. One target for improvement is the telemetry downlink, where significant resources are invested to acquire thousands of measurements for human interpretation. This cost-intensive method is used because conventional operations are not based on formal methodologies but on experiential reasoning and incrementally adapted procedures. Therefore, to improve the telemetry downlink it is first necessary to invent a rational framework for discussing operations. This research explores operations as a feedback control problem, develops the conceptual basis for the use of spacecraft telemetry, and presents a method to improve performance. The method is called summarization, a process to make vehicle data more useful to operators. Summarization enables rational trades for telemetry downlink by defining and quantitatively ranking these elements: all operational decisions, the knowledge needed to inform each decision, and all possible sensor mappings to acquire that knowledge. Summarization methods were implemented for the Sapphire microsatellite; conceptual health management and system models were developed and a degree-of-observability metric was defined. An automated tool was created to generate summarization methods from these models. Methods generated using a Sapphire model were compared against the conventional operations plan. Summarization was shown to identify the key decisions and isolate the most appropriate sensors. Secondly, a form of summarization called beacon monitoring was experimentally verified. Beacon monitoring automates the anomaly detection and notification tasks and migrates these responsibilities to the space segment. A

  2. Wind and turbine characteristics needed for integration of wind turbine arrays into a utility system

    NASA Technical Reports Server (NTRS)

    Park, G. L.

    1982-01-01

    Wind data and wind turbine generator (WTG) performance characteristics are often available in a form inconvenient for use by utility planners and engineers. The steps used by utility planners are summarized and the type of wind and WTG data needed for integration of WTG arrays suggested. These included long term yearly velocity averages for preliminary site feasibility, hourly velocities on a 'wind season' basis for more detailed economic analysis and for reliability studies, worst-case velocity profiles for gusts, and various minute-to-hourly velocity profiles for estimating the effect of longer-term wind fluctuations on utility operations. wind turbine data needed includes electrical properties of the generator, startup and shutdown characteristics, protection characteristics, pitch control response and control strategy, and electro-mechanical model for stability analysis.

  3. Joint Video Summarization and Transmission Adaptation for Energy-Efficient Wireless Video Streaming

    NASA Astrophysics Data System (ADS)

    Li, Zhu; Zhai, Fan; Katsaggelos, Aggelos K.

    2008-12-01

    The deployment of the higher data rate wireless infrastructure systems and the emerging convergence of voice, video, and data services have been driving various modern multimedia applications, such as video streaming and mobile TV. However, the greatest challenge for video transmission over an uplink multiaccess wireless channel is the limited channel bandwidth and battery energy of a mobile device. In this paper, we pursue an energy-efficient video communication solution through joint video summarization and transmission adaptation over a slow fading wireless channel. Video summarization, coding and modulation schemes, and packet transmission are optimally adapted to the unique packet arrival and delay characteristics of the video summaries. In addition to the optimal solution, we also propose a heuristic solution that has close-to-optimal performance. Operational energy efficiency versus video distortion performance is characterized under a summarization setting. Simulation results demonstrate the advantage of the proposed scheme in energy efficiency and video transmission quality.

  4. Automated Summarization of Publications Associated with Adverse Drug Reactions from PubMed

    PubMed Central

    Finkelstein, Joseph; Chen, Qinlang; Adams, Hayden; Friedman, Carol

    2016-01-01

    Academic literature provides rich and up-to-date information concerning adverse drug reactions (ADR), but it is time consuming and labor intensive for physicians to obtain information of ADRs from academic literature because they would have to generate queries, review retrieved articles and summarize the results. In this study, a method is developed to automatically detect and summarize ADRs from journal articles, rank them and present them to physicians in a user-friendly interface. The method studied ADRs for 6 drugs and returned on average 4.8 ADRs that were correct. The results demonstrated this method was feasible and effective. This method can be applied in clinical practice for assisting physicians to efficiently obtain information about ADRs associated with specific drugs. Automated summarization of ADR information from recent publications may facilitate translation of academic research into actionable information at point of care. PMID:27570654

  5. Automatic Summarization of MEDLINE Citations for Evidence–Based Medical Treatment: A Topic-Oriented Evaluation

    PubMed Central

    Fiszman, Marcelo; Demner-Fushman, Dina; Kilicoglu, Halil; Rindflesch, Thomas C.

    2009-01-01

    As the number of electronic biomedical textual resources increases, it becomes harder for physicians to find useful answers at the point of care. Information retrieval applications provide access to databases; however, little research has been done on using automatic summarization to help navigate the documents returned by these systems. After presenting a semantic abstraction automatic summarization system for MEDLINE citations, we concentrate on evaluating its ability to identify useful drug interventions for fifty-three diseases. The evaluation methodology uses existing sources of evidence-based medicine as surrogates for a physician-annotated reference standard. Mean average precision (MAP) and a clinical usefulness score developed for this study were computed as performance metrics. The automatic summarization system significantly outperformed the baseline in both metrics. The MAP gain was 0.17 (p < 0.01) and the increase in the overall score of clinical usefulness was 0.39 (p < 0.05). PMID:19022398

  6. The Effects of Summarization Instruction on Text Comprehension of Students with Learning Disabilities.

    ERIC Educational Resources Information Center

    Gajria, Meenakshi; Salvia, John

    1992-01-01

    This study, with 30 students with learning disabilities (grades 6-9) and 15 nondisabled students, found that instruction in a 5-rule summarization strategy significantly increased reading comprehension of expository prose. Strategy use was maintained over time, and students were reported to generalize its use. (Author/DB)

  7. A Comparison of Two Strategies for Teaching Third Graders to Summarize Information Text

    ERIC Educational Resources Information Center

    Dromsky, Ann Marie

    2011-01-01

    Summarizing text is one of the most effective comprehension strategies (National Institute of Child Health and Human Development, 2000) and an effective way to learn from information text (Dole, Duffy, Roehler, & Pearson, 1991; Pressley & Woloshyn, 1995). In addition, much research supports the explicit instruction of such strategies as…

  8. Utilizing Marzano's Summarizing and Note Taking Strategies on Seventh Grade Students' Mathematics Performance

    ERIC Educational Resources Information Center

    Jeanmarie-Gardner, Charmaine

    2013-01-01

    A quasi-experimental research study was conducted that investigated the academic impact of utilizing Marzano's summarizing and note taking strategies on mathematic achievement. A sample of seventh graders from a middle school located on Long Island's North Shore was tested to determine whether significant differences existed in mathematic test…

  9. Effects on Science Summarization of a Reading Comprehension Intervention for Adolescents with Behavior and Attention Disorders

    ERIC Educational Resources Information Center

    Rogevich, Mary E.; Perin, Dolores

    2008-01-01

    Sixty-three adolescent boys with behavioral disorders (BD), 31 of whom had comorbid attention deficit hyperactivity disorder (ADHD), participated in a self-regulated strategy development intervention called Think Before Reading, Think While Reading, Think After Reading, With Written Summarization (TWA-WS). TWA-WS adapted Linda Mason's TWA…

  10. Empirical Analysis of Exploiting Review Helpfulness for Extractive Summarization of Online Reviews

    ERIC Educational Resources Information Center

    Xiong, Wenting; Litman, Diane

    2014-01-01

    We propose a novel unsupervised extractive approach for summarizing online reviews by exploiting review helpfulness ratings. In addition to using the helpfulness ratings for review-level filtering, we suggest using them as the supervision of a topic model for sentence-level content scoring. The proposed method is metadata-driven, requiring no…

  11. iBIOMES Lite: Summarizing Biomolecular Simulation Data in Limited Settings

    PubMed Central

    2015-01-01

    As the amount of data generated by biomolecular simulations dramatically increases, new tools need to be developed to help manage this data at the individual investigator or small research group level. In this paper, we introduce iBIOMES Lite, a lightweight tool for biomolecular simulation data indexing and summarization. The main goal of iBIOMES Lite is to provide a simple interface to summarize computational experiments in a setting where the user might have limited privileges and limited access to IT resources. A command-line interface allows the user to summarize, publish, and search local simulation data sets. Published data sets are accessible via static hypertext markup language (HTML) pages that summarize the simulation protocols and also display data analysis graphically. The publication process is customized via extensible markup language (XML) descriptors while the HTML summary template is customized through extensible stylesheet language (XSL). iBIOMES Lite was tested on different platforms and at several national computing centers using various data sets generated through classical and quantum molecular dynamics, quantum chemistry, and QM/MM. The associated parsers currently support AMBER, GROMACS, Gaussian, and NWChem data set publication. The code is available at https://github.com/jcvthibault/ibiomes. PMID:24830957

  12. Enhancing Summarization Skills Using Twin Texts: Instruction in Narrative and Expository Text Structures

    ERIC Educational Resources Information Center

    Furtado, Leena; Johnson, Lisa

    2010-01-01

    This action-research case study endeavors to enhance the summarization skills of first grade students who are reading at or above the third grade level during the first trimester of the academic school year. Students read "twin text" sources, meaning, fiction and nonfiction literary selections focusing on a common theme to help identify and…

  13. iBIOMES Lite: summarizing biomolecular simulation data in limited settings.

    PubMed

    Thibault, Julien C; Cheatham, Thomas E; Facelli, Julio C

    2014-06-23

    As the amount of data generated by biomolecular simulations dramatically increases, new tools need to be developed to help manage this data at the individual investigator or small research group level. In this paper, we introduce iBIOMES Lite, a lightweight tool for biomolecular simulation data indexing and summarization. The main goal of iBIOMES Lite is to provide a simple interface to summarize computational experiments in a setting where the user might have limited privileges and limited access to IT resources. A command-line interface allows the user to summarize, publish, and search local simulation data sets. Published data sets are accessible via static hypertext markup language (HTML) pages that summarize the simulation protocols and also display data analysis graphically. The publication process is customized via extensible markup language (XML) descriptors while the HTML summary template is customized through extensible stylesheet language (XSL). iBIOMES Lite was tested on different platforms and at several national computing centers using various data sets generated through classical and quantum molecular dynamics, quantum chemistry, and QM/MM. The associated parsers currently support AMBER, GROMACS, Gaussian, and NWChem data set publication. The code is available at https://github.com/jcvthibault/ibiomes . PMID:24830957

  14. Science Text Comprehension: Drawing, Main Idea Selection, and Summarizing as Learning Strategies

    ERIC Educational Resources Information Center

    Leopold, Claudia; Leutner, Detlev

    2012-01-01

    The purpose of two experiments was to contrast instructions to generate drawings with two text-focused strategies--main idea selection (Exp. 1) and summarization (Exp. 2)--and to examine whether these strategies could help students learn from a chemistry science text. Both experiments followed a 2 x 2 design, with drawing strategy instructions…

  15. A Qualitative Study on the Use of Summarizing Strategies in Elementary Education

    ERIC Educational Resources Information Center

    Susar Kirmizi, Fatma; Akkaya, Nevin

    2011-01-01

    The objective of this study is to reveal how well summarizing strategies are used by Grade 4 and Grade 5 students as a reading comprehension strategy. This study was conducted in Buca, Izmir and the document analysis method, a qualitative research strategy, was employed. The study used a text titled "Environmental Pollution" and an "Evaluation…

  16. Summarizing scale-free networks based on virtual and real links

    NASA Astrophysics Data System (ADS)

    Bei, Yijun; Lin, Zhen; Chen, Deren

    2016-02-01

    Techniques to summarize and cluster graphs are indispensable to understand the internal characteristics of large complex networks. However, existing methods that analyze graphs mainly focus on aggregating strong-interaction vertices into the same group without considering the node properties, particularly multi-valued attributes. This study aims to develop a unified framework based on the concept of a virtual graph by integrating attributes and structural similarities. We propose a summarizing graph based on virtual and real links (SGVR) approach to aggregate similar nodes in a scale-free graph into k non-overlapping groups based on user-selected attributes considering both virtual links (attributes) and real links (graph structures). An effective data structure called HB-Graph is adopted to adjust the subgroups and optimize the grouping results. Extensive experiments are carried out on actual and synthetic datasets. Results indicate that our proposed method is both effective and efficient.

  17. Final Technical Report summarizing Purdue research activities as part of the DOE JET Topical Collaboration

    SciTech Connect

    Molnar, Denes

    2015-09-01

    This report summarizes research activities at Purdue University done as part of the DOE JET Topical Collaboration. These mainly involve calculation of covariant radiative energy loss in the (Djordjevic-)Gyulassy-Levai-Vitev ((D)GLV) framework for relativistic A+A reactions at RHIC and LHC energies using realistic bulk medium evolution with both transverse and longitudinal expansion. The single PDF file provided also includes a report from the entire JET Collaboration.

  18. Luminescent Rare-earth-based Nanoparticles: A Summarized Overview of their Synthesis, Functionalization, and Applications.

    PubMed

    Escudero, Alberto; Carrillo-Carrión, Carolina; Zyuzin, Mikhail V; Parak, Wolfgang J

    2016-08-01

    Rare-earth-based nanoparticles are currently attracting wide research interest in material science, physics, chemistry, medicine, and biology due to their optical properties, their stability, and novel applications. We present in this review a summarized overview of the general and recent developments in their synthesis and functionalization. Their luminescent properties are also discussed, including the latest advances in the enhancement of their emission luminescence. Some of their more relevant and novel biomedical, analytical, and optoelectronic applications are also commented on. PMID:27573400

  19. Formalization and separation: A systematic basis for interpreting approaches to summarizing science for climate policy.

    PubMed

    Sundqvist, Göran; Bohlin, Ingemar; Hermansen, Erlend A T; Yearley, Steven

    2015-06-01

    In studies of environmental issues, the question of how to establish a productive interplay between science and policy is widely debated, especially in relation to climate change. The aim of this article is to advance this discussion and contribute to a better understanding of how science is summarized for policy purposes by bringing together two academic discussions that usually take place in parallel: the question of how to deal with formalization (structuring the procedures for assessing and summarizing research, e.g. by protocols) and separation (maintaining a boundary between science and policy in processes of synthesizing science for policy). Combining the two dimensions, we draw a diagram onto which different initiatives can be mapped. A high degree of formalization and separation are key components of the canonical image of scientific practice. Influential Science and Technology Studies analysts, however, are well known for their critiques of attempts at separation and formalization. Three examples that summarize research for policy purposes are presented and mapped onto the diagram: the Intergovernmental Panel on Climate Change, the European Union's Science for Environment Policy initiative, and the UK Committee on Climate Change. These examples bring out salient differences concerning how formalization and separation are dealt with. Discussing the space opened up by the diagram, as well as the limitations of the attraction to its endpoints, we argue that policy analyses, including much Science and Technology Studies work, are in need of a more nuanced understanding of the two crucial dimensions of formalization and separation. Accordingly, two analytical claims are presented, concerning trajectories, how organizations represented in the diagram move over time, and mismatches, how organizations fail to handle the two dimensions well in practice. PMID:26477199

  20. How to Summarize a 6,000-Word Paper in a Six-Minute Video Clip

    PubMed Central

    Vachon, Patrick; Daudelin, Genevieve; Hivon, Myriam

    2013-01-01

    As part of our research team's knowledge transfer and exchange (KTE) efforts, we created a six-minute video clip that summarizes, in plain language, a scientific paper that describes why and how three teams of academic entrepreneurs developed new health technologies. Recognizing that video-based KTE strategies can be a valuable tool for health services and policy researchers, this paper explains the constraints and sources of inspiration that shaped our video production process. Aiming to provide practical guidance, we describe the steps and tools that we used to identify, refine and package the key content of the scientific paper into an original video format. PMID:23968634

  1. How to summarize a 6,000-word paper in a six-minute video clip.

    PubMed

    Lehoux, Pascale; Vachon, Patrick; Daudelin, Genevieve; Hivon, Myriam

    2013-05-01

    As part of our research team's knowledge transfer and exchange (KTE) efforts, we created a six-minute video clip that summarizes, in plain language, a scientific paper that describes why and how three teams of academic entrepreneurs developed new health technologies. Recognizing that video-based KTE strategies can be a valuable tool for health services and policy researchers, this paper explains the constraints and sources of inspiration that shaped our video production process. Aiming to provide practical guidance, we describe the steps and tools that we used to identify, refine and package the key content of the scientific paper into an original video format. PMID:23968634

  2. The Extent to Which Pre-Service Turkish Language and Literature Teachers Could Apply Summarizing Rules in Informative Texts

    ERIC Educational Resources Information Center

    Görgen, Izzet

    2015-01-01

    The purpose of the present study is to determine the extent to which pre-service Turkish Language and Literature teachers possess summarizing skill. Answers to the following questions were sought in the study: What is the summarizing skill level of the pre-service Turkish Language and Literature teachers? Which of the summarizing rules are…

  3. Predicting Noise From Wind Turbines

    NASA Technical Reports Server (NTRS)

    Grosveld, Ferdinand W.

    1990-01-01

    Computer program WINDY predicts broadband noise spectra of horizontal-axis wind-turbine generators. Enables adequate assessment of impact of broadband wind-turbine noise. Effects of turbulence, trailing-edge wakes, and bluntness taken into account. Program has practical application in design and siting of wind-turbine machines acceptable to community. Written in GW-Basic.

  4. 75 FR 74042 - Intent To Prepare an Environmental Impact Statement and To Conduct Scoping Meetings...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-30

    ... consist of up to 100 wind turbine generators with a combined total generating capacity of 150 MW, located... probability of substantial natural resources conflicts. NextEra's siting process for the wind turbine strings... Meetings: Interconnection of the Proposed Crowned Ridge Wind Energy Center Project, South Dakota...

  5. Evidence Summarized in Attorneys' Closing Arguments Predicts Acquittals in Criminal Trials of Child Sexual Abuse

    PubMed Central

    Stolzenberg, Stacia N.; Lyon, Thomas D.

    2014-01-01

    Evidence summarized in attorney's closing arguments of criminal child sexual abuse cases (N = 189) was coded to predict acquittal rates. Ten variables were significant bivariate predictors; five variables significant at p < .01 were entered into a multivariate model. Cases were likely to result in an acquittal when the defendant was not charged with force, the child maintained contact with the defendant after the abuse occurred, or the defense presented a hearsay witness regarding the victim's statements, a witness regarding the victim's character, or a witness regarding another witnesses' character (usually the mother). The findings suggest that jurors might believe that child molestation is akin to a stereotype of violent rape and that they may be swayed by defense challenges to the victim's credibility and the credibility of those close to the victim. PMID:24920247

  6. Interactive exploration of surveillance video through action shot summarization and trajectory visualization.

    PubMed

    Meghdadi, Amir H; Irani, Pourang

    2013-12-01

    We propose a novel video visual analytics system for interactive exploration of surveillance video data. Our approach consists of providing analysts with various views of information related to moving objects in a video. To do this we first extract each object's movement path. We visualize each movement by (a) creating a single action shot image (a still image that coalesces multiple frames), (b) plotting its trajectory in a space-time cube and (c) displaying an overall timeline view of all the movements. The action shots provide a still view of the moving object while the path view presents movement properties such as speed and location. We also provide tools for spatial and temporal filtering based on regions of interest. This allows analysts to filter out large amounts of movement activities while the action shot representation summarizes the content of each movement. We incorporated this multi-part visual representation of moving objects in sViSIT, a tool to facilitate browsing through the video content by interactive querying and retrieval of data. Based on our interaction with security personnel who routinely interact with surveillance video data, we identified some of the most common tasks performed. This resulted in designing a user study to measure time-to-completion of the various tasks. These generally required searching for specific events of interest (targets) in videos. Fourteen different tasks were designed and a total of 120 min of surveillance video were recorded (indoor and outdoor locations recording movements of people and vehicles). The time-to-completion of these tasks were compared against a manual fast forward video browsing guided with movement detection. We demonstrate how our system can facilitate lengthy video exploration and significantly reduce browsing time to find events of interest. Reports from expert users identify positive aspects of our approach which we summarize in our recommendations for future video visual analytics systems

  7. Effects of learning structure and summarization during computer-based instruction

    NASA Astrophysics Data System (ADS)

    Werner, Lynn

    The purpose of this study was to investigate the effects of learning strategy and summarization within a computer-based chemistry and physics program. Students worked individually or in cooperative dyads to complete science instruction; half of them completed summaries over the instructional content when directed to do so. The study examined the effects of learning strategy and summarization on posttest and enroute performance, attitude, time-on-task, and interaction behaviors. Results indicated no significant differences for posttest performance. Results for enroute performance indicated that practice scores for students who did not write summaries were significantly higher than for those who wrote summaries. Enroute results did not indicate a significant difference between those working in cooperative dyads and those working alone. Results for time-on-task indicated a significant interaction between learning strategy and summary condition. Students in the cooperative-no summary condition spent significantly more time on practice than those in the cooperative-summary condition. Furthermore, subjects in the individual-no summary condition spent significantly more time on practice than those in the cooperative-summary condition. Attitudes toward the computer-based program were generally positive. Students expressed positive attitudes toward the interactive exercises, the atomic animations and the on-line, interactive periodic table. Attitude scores also showed that students expressed positive feelings about the particular learning strategy to which they were assigned. Results from the study also indicated that students in the two cooperative conditions interacted together in somewhat different ways. Dyads in the summary condition exhibited significantly more helping behaviors and task-related behaviors than dyads in the no summary condition. The results of this study have implications for the design of computer-based instruction and the use of this medium with

  8. Video summarization based tele-endoscopy: a service to efficiently manage visual data generated during wireless capsule endoscopy procedure.

    PubMed

    Mehmood, Irfan; Sajjad, Muhammad; Baik, Sung Wook

    2014-09-01

    Wireless capsule endoscopy (WCE) has great advantages over traditional endoscopy because it is portable and easy to use. More importantly, WCE combined with mobile computing ensures rapid transmission of diagnostic data to hospitals and enables off-site senior gastroenterologists to offer timely decision making support. However, during this WCE process, video data are produced in huge amounts, but only a limited amount of data is actually useful for diagnosis. The sharing and analysis of this video data becomes a challenging task due the constraints such as limited memory, energy, and communication capability. In order to facilitate efficient WCE data collection and browsing tasks, we present a video summarization-based tele-endoscopy service that estimates the semantically relevant video frames from the perspective of gastroenterologists. For this purpose, image moments, curvature, and multi-scale contrast are computed and are fused to obtain the saliency map of each frame. This saliency map is used to select keyframes. The proposed tele-endoscopy service selects keyframes based on their relevance to the disease diagnosis. This ensures the sending of diagnostically relevant frames to the gastroenterologist instead of sending all the data, thus saving transmission costs and bandwidth. The proposed framework also saves storage costs as well as the precious time of doctors in browsing patient's information. The qualitative and quantitative results are encouraging and show that the proposed service provides video keyframes to the gastroenterologists without discarding important information. PMID:25037715

  9. Design guided data analysis for summarizing systematic pattern defects and process window

    NASA Astrophysics Data System (ADS)

    Xie, Qian; Venkatachalam, Panneerselvam; Lee, Julie; Chen, Zhijin; Zafar, Khurram

    2016-03-01

    As the semiconductor process technology moves into more advanced nodes, design and process induced systematic defects become increasingly significant yield limiters. Therefore, early detection of these defects is crucial. Focus Exposure Matrix (FEM) and Process Window Qualification (PWQ) are routine methods for discovering systematic patterning defects and establishing the lithography process window. These methods require the stepper to expose a reticle onto the wafer at various focus and exposure settings (also known as modulations). The wafer is subsequently inspected by a bright field, broadband plasma or an E-Beam Inspection tool using a high sensitivity inspection recipe (i.e. hot scan) that often reports a million or more defects. Analyzing this vast stream of data to identify the weak patterns and arrive at the optimal focus/exposure settings requires a significant amount of data reduction through aggressive sampling and nuisance filtering schemes. However, these schemes increase alpha risk, i.e. the probability of not catching some systematic or otherwise important defects within a modulation and thus reporting that modulation as a good condition for production wafers. In order to reduce this risk and establish a more accurate process window, we describe a technique that introduces image-and-design integration methodologies into the inspection data analysis workflow. These image-and-design integration methodologies include contour extraction and alignment to design, contour-to-design defect detection, defective/nuisance pattern retrieval, confirmed defective/nuisance pattern overlay with inspection data, and modulation-related weak-pattern ranking. The technique we present provides greater automation, from defect detection to defective pattern retrieval to decision-making steps, that allows for statistically summarized results and increased coverage of the wafer to be achieved without an adverse impact on cycle time. Statistically summarized results, lead

  10. The Summarization of Pyro-shock Testing Data and SRS Level Prediction Methodology

    NASA Astrophysics Data System (ADS)

    Shi, Qinzhong; Ando, Shigemasa; Seko, Hiromi; Nagahama, Kenta; Saegusa, Hiroshi

    2004-08-01

    Mechanical separation through pyrotechnic shock is widely employed in space vehicle separation. These kinds of pyrotechnic shock devices produce transient loads with high levels of acceleration at different location of satellite. The prediction of acceleration level is significant for the definition of payload shock environment in the earlier design phase and selection of proper accelerometers in the test. This paper summarizes the shock response spectrum (SRS) from the pyrotechnical testing data of several typical satellites from the view points of distance from the source, complex equipment mount structure, etc. The empirical curve for the prediction possibility of pyrotechnic shock level is discussed. At first, the SRS distribution maps at the measure points were compared to understand the shock response environment which may differ from the distance attenuation from the shock source, effects of material and size of structural components, effects of joints and inserts of structural components, etc. Then, the paper discusses the prediction methodologies related to the empirical and extrapolation model presented by NASA-HDBK-7005 is compared to the testing data distribution of several satellites.

  11. Development of a Summarized Health Index (SHI) for Use in Predicting Survival in Sea Turtles

    PubMed Central

    Li, Tsung-Hsien; Chang, Chao-Chin; Cheng, I-Jiunn; Lin, Suen-Chuain

    2015-01-01

    Veterinary care plays an influential role in sea turtle rehabilitation, especially in endangered species. Physiological characteristics, hematological and plasma biochemistry profiles, are useful references for clinical management in animals, especially when animals are during the convalescence period. In this study, these factors associated with sea turtle surviving were analyzed. The blood samples were collected when sea turtles remained alive, and then animals were followed up for surviving status. The results indicated that significantly negative correlation was found between buoyancy disorders (BD) and sea turtle surviving (p < 0.05). Furthermore, non-surviving sea turtles had significantly higher levels of aspartate aminotranspherase (AST), creatinine kinase (CK), creatinine and uric acid (UA) than surviving sea turtles (all p < 0.05). After further analysis by multiple logistic regression model, only factors of BD, creatinine and UA were included in the equation for calculating summarized health index (SHI) for each individual. Through evaluation by receiver operating characteristic (ROC) curve, the result indicated that the area under curve was 0.920 ± 0.037, and a cut-off SHI value of 2.5244 showed 80.0% sensitivity and 86.7% specificity in predicting survival. Therefore, the developed SHI could be a useful index to evaluate health status of sea turtles and to improve veterinary care at rehabilitation facilities. PMID:25803431

  12. MeSH: a window into full text for document summarization

    PubMed Central

    Bhattacharya, Sanmitra; Ha−Thuc, Viet; Srinivasan, Padmini

    2011-01-01

    Motivation: Previous research in the biomedical text-mining domain has historically been limited to titles, abstracts and metadata available in MEDLINE records. Recent research initiatives such as TREC Genomics and BioCreAtIvE strongly point to the merits of moving beyond abstracts and into the realm of full texts. Full texts are, however, more expensive to process not only in terms of resources needed but also in terms of accuracy. Since full texts contain embellishments that elaborate, contextualize, contrast, supplement, etc., there is greater risk for false positives. Motivated by this, we explore an approach that offers a compromise between the extremes of abstracts and full texts. Specifically, we create reduced versions of full text documents that contain only important portions. In the long-term, our goal is to explore the use of such summaries for functions such as document retrieval and information extraction. Here, we focus on designing summarization strategies. In particular, we explore the use of MeSH terms, manually assigned to documents by trained annotators, as clues to select important text segments from the full text documents. Results: Our experiments confirm the ability of our approach to pick the important text portions. Using the ROUGE measures for evaluation, we were able to achieve maximum ROUGE-1, ROUGE-2 and ROUGE-SU4 F-scores of 0.4150, 0.1435 and 0.1782, respectively, for our MeSH term-based method versus the maximum baseline scores of 0.3815, 0.1353 and 0.1428, respectively. Using a MeSH profile-based strategy, we were able to achieve maximum ROUGE F-scores of 0.4320, 0.1497 and 0.1887, respectively. Human evaluation of the baselines and our proposed strategies further corroborates the ability of our method to select important sentences from the full texts. Contact: sanmitra-bhattacharya@uiowa.edu; padmini-srinivasan@uiowa.edu PMID:21685060

  13. Summarization of Injury and Fatality Factors Involving Children and Youth in Grain Storage and Handling Incidents.

    PubMed

    Issa, S F; Field, W E; Hamm, K E; Cheng, Y H; Roberts, M J; Riedel, S M

    2016-01-01

    This article summarizes data gathered on 246 documented cases of children and youth under the age of 21 involved in grain storage and handling incidents in agricultural workplaces from 1964 to 2013 in the U.S. that have been entered into the Purdue Agricultural Confined Space Incident Database. The database is the result of ongoing efforts to collect and file information on documented injuries, fatalities, and entrapments in all forms of agricultural confined spaces. While the frequency of injuries and fatalities involving children and youth in agriculture has decreased in recent years, incidents related to agricultural confined spaces, especially grain storage and handling facilities, have remained largely unchanged during the same period. Approximately 21% of all documented incidents involved children and youth (age 20 and younger), and more than 77% of all documented incidents were fatal, suggesting an under-reporting of non-fatal incidents. Findings indicate that the majority of youth incidents occurred at OSHA exempt agricultural worksites. The states reporting the most incidents were Indiana, Iowa, Nebraska, Illinois, and Minnesota. Grain transport vehicles represented a significant portion of incidents involving children under the age of 16. The overwhelming majority of victims were male, and most incidents (50%) occurred in June, October, and November. Recommendations include developing intervention strategies that target OSHA exempt farms, feedlots, and seed processing facilities; preparing engineering design and best practice standards that reduce the exposure of children and youth to agricultural confined spaces; and developing gender-specific safety resources that incorporate gender-sensitive strategies to communicate safety information to the population of young males with the greatest risk of exposure to the hazards of agricultural confined spaces. PMID:27024990

  14. Summarization of recent literature pertaining to an occupational health standard for cadmium. Final report

    SciTech Connect

    Not Available

    1980-06-01

    Available information on cadmium was reviewed. Topics discussed included human and animal toxicology, analytical and sampling methods, work practices, and engineering controls. Studies have shown that cadmium is absorbed by the body and distributed to various tissues with the lungs and gastrointestinal tract providing the primary routes of intake and adsorption. Industrial exposure arises mainly through inhalation of cadmium dusts and fumes. Cigarette smoking significantly increases exposure to cadmium through this route. Fumes and dusts produce acute and chronic lung disease and chronic systemic disease. Occupational exposure to cadmium is frequently involved simultaneous with exposure to other metals, complicating the problem of isolating a single causative agent. The kidney is the critical organ for long term effects. The liver is considered to be one of the primary sites of cadmium accumulation and a major site of detoxification. Evidence for cadmium induced hypertension is still unclear. There is little human data concerning the transfer of cadmium across the placenta, uptake and distribution of cadmium in the embryo and fetus, and teratogenic effects. Available data fail to provide conclusive evidence that cadmium causes cancer.

  15. Humans in Space: Summarizing the Medico-Biological Results of the Space Shuttle Program

    NASA Technical Reports Server (NTRS)

    Risin, Diana; Stepaniak, P. C.; Grounds, D. J.

    2011-01-01

    As we celebrate the 50th anniversary of Gagarin's flight that opened the era of Humans in Space we also commemorate the 30th anniversary of the Space Shuttle Program (SSP) which was triumphantly completed by the flight of STS-135 on July 21, 2011. These were great milestones in the history of Human Space Exploration. Many important questions regarding the ability of humans to adapt and function in space were answered for the past 50 years and many lessons have been learned. Significant contribution to answering these questions was made by the SSP. To ensure the availability of the Shuttle Program experiences to the international space community NASA has made a decision to summarize the medico-biological results of the SSP in a fundamental edition that is scheduled to be completed by the end of 2011 beginning 2012. The goal of this edition is to define the normal responses of the major physiological systems to short-duration space flights and provide a comprehensive source of information for planning, ensuring successful operational activities and for management of potential medical problems that might arise during future long-term space missions. The book includes the following sections: 1. History of Shuttle Biomedical Research and Operations; 2. Medical Operations Overview Systems, Monitoring, and Care; 3. Biomedical Research Overview; 4. System-specific Adaptations/Responses, Issues, and Countermeasures; 5. Multisystem Issues and Countermeasures. In addition, selected operational documents will be presented in the appendices. The chapters are written by well-recognized experts in appropriate fields, peer reviewed, and edited by physicians and scientists with extensive expertise in space medical operations and space-related biomedical research. As Space Exploration continues the major question whether humans are capable of adapting to long term presence and adequate functioning in space habitats remains to be answered We expect that the comprehensive review of

  16. Rare-Earth-Free Nanostructure Magnets: Rare-Earth-Free Permanent Magnets for Electric Vehicle Motors and Wind Turbine Generators: Hexagonal Symmetry Based Materials Systems Mn-Bi and M-type Hexaferrite

    SciTech Connect

    2012-01-01

    REACT Project: The University of Alabama is developing new iron- and manganese-based composite materials for use in the electric motors of EVs and renewable power generators that will demonstrate magnetic properties superior to today’s best rare-earth-based magnets. Rare earths are difficult and expensive to refine. EVs and renewable power generators typically use rare earths to make their electric motors smaller and more powerful. The University of Alabama has the potential to improve upon the performance of current state-of-the-art rare-earth-based magnets using low-cost and more abundant materials such as manganese and iron. The ultimate goal of this project is to demonstrate improved performance in a full-size prototype magnet at reduced cost.

  17. Summarizing comments on the discussion and a prospectus for urgent future action.

    PubMed

    Thomas, John Meurig

    2016-02-28

    Following my personal reactions to some of the key points made in this Discussion (Part I), I present, in Part II, what I perceive to be the most important, and, in some cases, urgent actions that now need to be taken in the following inter-related fields: (i) design of catalysts, especially for the production of materials using anthropogenic carbon dioxide, CO2, as feedstock; (ii) the continuing role of catalysis in the protection of the environment; (iii) the importance of catalysis in the generation of fuel and the release of energy; and (iv) the wisdom of conducting life cycle and techno-economic analyses continually during the development of new catalysts, as well as of those in regular use. A brief account is also given of the prospect of designing atom-efficient catalysts in which either atomically dispersed rare (and expensive) metals such as Ir or Pt or the use of single-site earth-abundant elements (Al, Si, O) can be employed to facilitate important industrial reactions. PMID:26755761

  18. Site environmental programs

    SciTech Connect

    Schmidt, J.W.; Hanf, R.W.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the site environmental programs. Effluent monitoring and environmental surveillance programs monitor for impacts from operations in several areas. The first area consists of the point of possible release into the environment. The second area consists of possible contamination adjacent to DOE facilities, and the third area is the general environment both on and off the site.

  19. Opinion Integration and Summarization

    ERIC Educational Resources Information Center

    Lu, Yue

    2011-01-01

    As Web 2.0 applications become increasingly popular, more and more people express their opinions on the Web in various ways in real time. Such wide coverage of topics and abundance of users make the Web an extremely valuable source for mining people's opinions about all kinds of topics. However, since the opinions are usually expressed as…

  20. Biomedical text summarization to support genetic database curation: using Semantic MEDLINE to create a secondary database of genetic information

    PubMed Central

    Fiszman, Marcelo; Hurdle, John F; Rindflesch, Thomas C

    2010-01-01

    Objective: This paper examines the development and evaluation of an automatic summarization system in the domain of molecular genetics. The system is a potential component of an advanced biomedical information management application called Semantic MEDLINE and could assist librarians in developing secondary databases of genetic information extracted from the primary literature. Methods: An existing summarization system was modified for identifying biomedical text relevant to the genetic etiology of disease. The summarization system was evaluated on the task of identifying data describing genes associated with bladder cancer in MEDLINE citations. A gold standard was produced using records from Genetics Home Reference and Online Mendelian Inheritance in Man. Genes in text found by the system were compared to the gold standard. Recall, precision, and F-measure were calculated. Results: The system achieved recall of 46%, and precision of 88% (F-measure = 0.61) by taking Gene References into Function (GeneRIFs) into account. Conclusion: The new summarization schema for genetic etiology has potential as a component in Semantic MEDLINE to support the work of data curators. PMID:20936065

  1. Statement Summarizing Research Findings on the Issue of the Relationship Between Food-Additive-Free Diets and Hyperkinesis in Children.

    ERIC Educational Resources Information Center

    Lipton, Morris; Wender, Esther

    The National Advisory Committee on Hyperkinesis and Food Additives paper summarized some research findings on the issue of the relationship between food-additive-free diets and hyperkinesis in children. Based on several challenge studies, it is concluded that the evidence generally refutes Dr. B. F. Feingold's claim that artificial colorings in…

  2. Stimulating Graphical Summarization in Late Elementary Education: The Relationship between Two Instructional Mind-Map Approaches and Student Characteristics

    ERIC Educational Resources Information Center

    Merchie, Emmelien; Van Keer, Hilde

    2016-01-01

    This study examined the effectiveness of two instructional mind-mapping approaches to stimulate fifth and sixth graders' graphical summarization skills. Thirty-five fifth- and sixth-grade teachers and 644 students from 17 different elementary schools participated. A randomized quasi-experimental repeated-measures design was set up with two…

  3. The Effect of a Summarization-Based Cumulative Retelling Strategy on Listening Comprehension of College Students with Visual Impairments

    ERIC Educational Resources Information Center

    Tuncer, A. Tuba; Altunay, Banu

    2006-01-01

    Because students with visual impairments need auditory materials in order to access information, listening comprehension skills are important to their academic success. The present study investigated the effectiveness of summarization-based cumulative retelling strategy on the listening comprehension of four visually impaired college students. An…

  4. Usability evaluation of an experimental text summarization system and three search engines: implications for the reengineering of health care interfaces.

    PubMed Central

    Kushniruk, Andre W.; Kan, Min-Yem; McKeown, Kathleen; Klavans, Judith; Jordan, Desmond; LaFlamme, Mark; Patel, Vimia L.

    2002-01-01

    This paper describes the comparative evaluation of an experimental automated text summarization system, Centrifuser and three conventional search engines - Google, Yahoo and About.com. Centrifuser provides information to patients and families relevant to their questions about specific health conditions. It then produces a multidocument summary of articles retrieved by a standard search engine, tailored to the user's question. Subjects, consisting of friends or family of hospitalized patients, were asked to "think aloud" as they interacted with the four systems. The evaluation involved audio- and video recording of subject interactions with the interfaces in situ at a hospital. Results of the evaluation show that subjects found Centrifuser's summarization capability useful and easy to understand. In comparing Centrifuser to the three search engines, subjects' ratings varied; however, specific interface features were deemed useful across interfaces. We conclude with a discussion of the implications for engineering Web-based retrieval systems. PMID:12463858

  5. Combining information on multiple instrumental variables in Mendelian randomization: comparison of allele score and summarized data methods.

    PubMed

    Burgess, Stephen; Dudbridge, Frank; Thompson, Simon G

    2016-05-20

    Mendelian randomization is the use of genetic instrumental variables to obtain causal inferences from observational data. Two recent developments for combining information on multiple uncorrelated instrumental variables (IVs) into a single causal estimate are as follows: (i) allele scores, in which individual-level data on the IVs are aggregated into a univariate score, which is used as a single IV, and (ii) a summary statistic method, in which causal estimates calculated from each IV using summarized data are combined in an inverse-variance weighted meta-analysis. To avoid bias from weak instruments, unweighted and externally weighted allele scores have been recommended. Here, we propose equivalent approaches using summarized data and also provide extensions of the methods for use with correlated IVs. We investigate the impact of different choices of weights on the bias and precision of estimates in simulation studies. We show that allele score estimates can be reproduced using summarized data on genetic associations with the risk factor and the outcome. Estimates from the summary statistic method using external weights are biased towards the null when the weights are imprecisely estimated; in contrast, allele score estimates are unbiased. With equal or external weights, both methods provide appropriate tests of the null hypothesis of no causal effect even with large numbers of potentially weak instruments. We illustrate these methods using summarized data on the causal effect of low-density lipoprotein cholesterol on coronary heart disease risk. It is shown that a more precise causal estimate can be obtained using multiple genetic variants from a single gene region, even if the variants are correlated. © 2015 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd. PMID:26661904

  6. An Automatic Multidocument Text Summarization Approach Based on Naïve Bayesian Classifier Using Timestamp Strategy

    PubMed Central

    Ramanujam, Nedunchelian; Kaliappan, Manivannan

    2016-01-01

    Nowadays, automatic multidocument text summarization systems can successfully retrieve the summary sentences from the input documents. But, it has many limitations such as inaccurate extraction to essential sentences, low coverage, poor coherence among the sentences, and redundancy. This paper introduces a new concept of timestamp approach with Naïve Bayesian Classification approach for multidocument text summarization. The timestamp provides the summary an ordered look, which achieves the coherent looking summary. It extracts the more relevant information from the multiple documents. Here, scoring strategy is also used to calculate the score for the words to obtain the word frequency. The higher linguistic quality is estimated in terms of readability and comprehensibility. In order to show the efficiency of the proposed method, this paper presents the comparison between the proposed methods with the existing MEAD algorithm. The timestamp procedure is also applied on the MEAD algorithm and the results are examined with the proposed method. The results show that the proposed method results in lesser time than the existing MEAD algorithm to execute the summarization process. Moreover, the proposed method results in better precision, recall, and F-score than the existing clustering with lexical chaining approach. PMID:27034971

  7. Mobile-Cloud Assisted Video Summarization Framework for Efficient Management of Remote Sensing Data Generated by Wireless Capsule Sensors

    PubMed Central

    Mehmood, Irfan; Sajjad, Muhammad; Baik, Sung Wook

    2014-01-01

    Wireless capsule endoscopy (WCE) has great advantages over traditional endoscopy because it is portable and easy to use, especially in remote monitoring health-services. However, during the WCE process, the large amount of captured video data demands a significant deal of computation to analyze and retrieve informative video frames. In order to facilitate efficient WCE data collection and browsing task, we present a resource- and bandwidth-aware WCE video summarization framework that extracts the representative keyframes of the WCE video contents by removing redundant and non-informative frames. For redundancy elimination, we use Jeffrey-divergence between color histograms and inter-frame Boolean series-based correlation of color channels. To remove non-informative frames, multi-fractal texture features are extracted to assist the classification using an ensemble-based classifier. Owing to the limited WCE resources, it is impossible for the WCE system to perform computationally intensive video summarization tasks. To resolve computational challenges, mobile-cloud architecture is incorporated, which provides resizable computing capacities by adaptively offloading video summarization tasks between the client and the cloud server. The qualitative and quantitative results are encouraging and show that the proposed framework saves information transmission cost and bandwidth, as well as the valuable time of data analysts in browsing remote sensing data. PMID:25225874

  8. An Automatic Multidocument Text Summarization Approach Based on Naïve Bayesian Classifier Using Timestamp Strategy.

    PubMed

    Ramanujam, Nedunchelian; Kaliappan, Manivannan

    2016-01-01

    Nowadays, automatic multidocument text summarization systems can successfully retrieve the summary sentences from the input documents. But, it has many limitations such as inaccurate extraction to essential sentences, low coverage, poor coherence among the sentences, and redundancy. This paper introduces a new concept of timestamp approach with Naïve Bayesian Classification approach for multidocument text summarization. The timestamp provides the summary an ordered look, which achieves the coherent looking summary. It extracts the more relevant information from the multiple documents. Here, scoring strategy is also used to calculate the score for the words to obtain the word frequency. The higher linguistic quality is estimated in terms of readability and comprehensibility. In order to show the efficiency of the proposed method, this paper presents the comparison between the proposed methods with the existing MEAD algorithm. The timestamp procedure is also applied on the MEAD algorithm and the results are examined with the proposed method. The results show that the proposed method results in lesser time than the existing MEAD algorithm to execute the summarization process. Moreover, the proposed method results in better precision, recall, and F-score than the existing clustering with lexical chaining approach. PMID:27034971

  9. Mobile-cloud assisted video summarization framework for efficient management of remote sensing data generated by wireless capsule sensors.

    PubMed

    Mehmood, Irfan; Sajjad, Muhammad; Baik, Sung Wook

    2014-01-01

    Wireless capsule endoscopy (WCE) has great advantages over traditional endoscopy because it is portable and easy to use, especially in remote monitoring health-services. However, during the WCE process, the large amount of captured video data demands a significant deal of computation to analyze and retrieve informative video frames. In order to facilitate efficient WCE data collection and browsing task, we present a resource- and bandwidth-aware WCE video summarization framework that extracts the representative keyframes of the WCE video contents by removing redundant and non-informative frames. For redundancy elimination, we use Jeffrey-divergence between color histograms and inter-frame Boolean series-based correlation of color channels. To remove non-informative frames, multi-fractal texture features are extracted to assist the classification using an ensemble-based classifier. Owing to the limited WCE resources, it is impossible for the WCE system to perform computationally intensive video summarization tasks. To resolve computational challenges, mobile-cloud architecture is incorporated, which provides resizable computing capacities by adaptively offloading video summarization tasks between the client and the cloud server. The qualitative and quantitative results are encouraging and show that the proposed framework saves information transmission cost and bandwidth, as well as the valuable time of data analysts in browsing remote sensing data. PMID:25225874

  10. CERCLA Site discharges to POTWs CERCLA site sampling program: Detailed data report

    SciTech Connect

    Not Available

    1990-08-01

    The document contains wastewater data obtained from sampling at seventeen CERCLA sites during a study of wastewater discharges from CERCLA sites to publicly owned treatment works (POTWs). The document serves as an appendix to the report summarizing the findings of the CERCLA site sampling program in Section 3 (CERCLA Site Data Report) in the USEPA CERCLA Site Discharges to POTWs Treatability Manual.