Assessment of Gearbox Operational Loads and Reliability under High Mean Wind Speeds

DEFF Research Database (Denmark)

Dabrowski, Dariusz; Natarajan, Anand

2015-01-01

wind turbine that operates in storm conditions with mean wind speeds less than 30 m/s is presented. In the study, normal shut-downs of a wind turbine in storm conditions were investigated. The analysis were conducted for two storm control strategies and different wind conditions from an extreme...... operating gust, normal turbulence model and extreme turbulence model. In the paper, loads in the planetary gear are quantified as well as the torsional moments in the main shaft. On the basis of simulation results the annual probability of failure of the gearbox in a wind turbine with soft storm controller...... is calculated, and compared with the one had the gearbox working in a wind turbine operating with hard storm controller. In the study, it was found that normal shut-downs do not have a significant influence on the ultimate loads in the gearbox, since they are related mostly to the gusts occurring during...

Effect of Different Workscope Strategies on Wind Turbine Gearbox Life Cycle Repair Costs

Directory of Open Access Journals (Sweden)

D. Crowley

2013-01-01

Full Text Available The wind turbine industry is beginning to establish orthodoxies governing the repair of gearboxes, including policies governing the replacement of bearings during gearbox heavy maintenance events. Some maintainers recommend replacing all of the bearings, every time, regardless of condition or age. At the same time, others prefer to only replace the failed bearing. The former rationale achieves availability by spending more money than absolutely necessary; the latter sacrifices reliability in exchange for a lower shop visit cost. Even though neither approach results in the lowest Life Cycle Cost, no standard practice has yet been implemented to methodically determine what would be the best approach. Furthermore, as gearboxes approach the end of their planned service lives, a different strategy may be called-for. This paper presents an example of using a reliability-based statistical analysis to determine which strategy will yield the lowest Life Cycle Cost for wind turbine gearboxes.

Advanced Prop-fan Engine Technology (APET) single- and counter-rotation gearbox/pitch change mechanism

Science.gov (United States)

Reynolds, C. N.

1985-01-01

The preliminary design of advanced technology (1992) turboprop engines for single-rotation prop-fans and conceptual designs of pitch change mechanisms for single- and counter-rotation prop-fan application are discussed. The single-rotation gearbox is a split path, in-line configuration. The counter-rotation gearbox is an in-line, differential planetary design. The pitch change mechanisms for both the single- and counter-rotation arrangements are rotary/hydraulic. The advanced technology single-rotation gearbox yields a 2.4 percent improvement in aircraft fuel burn and a one percent improvement in operating cost relative to a current technology gearbox. The 1992 counter-rotation gearbox is 15 percent lighter, 15 percent more reliable, 5 percent lower in cost, and 45 percent lower in maintenance cost than the 1992 single-rotation gearbox. The pitch controls are modular, accessible, and external.

Gearbox vibration diagnostic analyzer

Science.gov (United States)

1992-01-01

This report describes the Gearbox Vibration Diagnostic Analyzer installed in the NASA Lewis Research Center's 500 HP Helicopter Transmission Test Stand to monitor gearbox testing. The vibration of the gearbox is analyzed using diagnostic algorithms to calculate a parameter indicating damaged components.

Development of a 5 MW reference gearbox for offshore wind turbines: 5 MW reference gearbox

Energy Technology Data Exchange (ETDEWEB)

Nejad, Amir Rasekhi [Norwegian Research Center for Offshore Wind Technology, Norwegian University of Science and Technology, Trondheim Norway; Center for Ships and Ocean Structures, Norwegian University of Science and Technology, Trondheim Norway; Guo, Yi [National Wind Technology Center, National Renewable Energy Laboratory, Golden Colorado USA; Gao, Zhen [Center for Ships and Ocean Structures, Norwegian University of Science and Technology, Trondheim Norway; Moan, Torgeir [Norwegian Research Center for Offshore Wind Technology, Norwegian University of Science and Technology, Trondheim Norway; Center for Ships and Ocean Structures, Norwegian University of Science and Technology, Trondheim Norway

2015-07-27

This paper presents detailed descriptions, modeling parameters and technical data of a 5MW high-speed gearbox developed for the National Renewable Energy Laboratory offshore 5MW baseline wind turbine. The main aim of this paper is to support the concept studies and research for large offshore wind turbines by providing a baseline gearbox model with detailed modeling parameters. This baseline gearbox follows the most conventional design types of those used in wind turbines. It is based on the four-point supports: two main bearings and two torque arms. The gearbox consists of three stages: two planetary and one parallel stage gears. The gear ratios among the stages are calculated in a way to obtain the minimum gearbox weight. The gearbox components are designed and selected based on the offshore wind turbine design codes and validated by comparison to the data available from large offshore wind turbine prototypes. All parameters required to establish the dynamic model of the gearbox are then provided. Moreover, a maintenance map indicating components with high to low probability of failure is shown. The 5 MW reference gearbox can be used as a baseline for research on wind turbine gearboxes and comparison studies. It can also be employed in global analysis tools to represent a more realistic model of a gearbox in a coupled analysis.

A bearingless coaxial magnetic gearbox

Directory of Open Access Journals (Sweden)

A.S. Abdel-Khalik

2014-09-01

Full Text Available Recently, magnetic gearboxes (MGBs are serious contenders to their conventional mechanical counterparts in terms of reduced maintenance requirements, improved reliability, tolerance to mechanical inaccuracies, and inherent overload protection. MGBs are preferably employed in high speed applications and compact harsh environments subjected to severe shock and vibration. A high gear ratio MGB is also a suitable candidate for single stage high-speed transmission applications such as helicopter power transmissions. In this paper, the conventional planetary magnetic gearbox is equipped with a three-phase winding to provide additional magnetic levitation capabilities besides torque transmission, thus creating a bearingless MGB configuration. This was achieved by adding a three-phase winding in the space between the ferromagnetic pieces. The current in this additional winding is controlled to provide decoupled axial forces irrespective of the transmitted mechanical power. This feature is important to reduce the mechanical losses especially for high-speed rotors and can be a viable method for vibration suppression.

Side-band algorithm for automatic wind turbine gearbox fault detection and diagnosis.

OpenAIRE

Zappalá, D.; Tavner, P.J.; Crabtree, C.J.; Sheng, S.

2014-01-01

Improving the availability of wind turbines is critical for minimising the cost of wind energy, especially offshore. The development of reliable and cost-effective gearbox condition monitoring systems (CMSs) is of concern to the wind industry, because the gearbox downtime has a significant effect on the wind turbine availabilities. Timely detection and diagnosis of developing gear defects is essential for minimising an unplanned downtime. One of the main limitations of most current CMSs is th...

Gearbox Instrumentation for the Investigation of Bearing Axial Cracking

Energy Technology Data Exchange (ETDEWEB)

Keller, Jonathan A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Lambert, Scott R [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2018-03-27

Failures in gearbox bearings have been the primary source of reliability issues for wind turbine drivetrains, leading to costly downtime and unplanned maintenance. The most common failure mode is attributed to so-called axial cracks or white-etching cracks, which primarily affect the intermediate and high-speed-stage bearings. The high-speed-shaft and bearing loads and sliding will be measured with a specially instrumented gearbox installed in a 1.5-megawatt turbine at the National Wind Technology Center in an upcoming test campaign. Additional instrumentation will also measure the tribological environment of these bearings, including bearing temperatures, lubricant temperature and water content, air temperature and humidity, and stray electrical current across the bearings. This paper fully describes the instrumentation package and summarizes initial results.

The Strength Analysis of Differential Planetary Gears of Gearbox for Concrete Mixer Truck

Science.gov (United States)

Bae, M. H.; Bae, T. Y.; Kim, D. J.

2018-03-01

The power train of mixer gearbox for concrete mixer truck includes differential planetary gears to get large reduction ratio for operating mixer a drum and simple structure. The planetary gears are very important part of a mixer gearbox where strength problems namely gear bending stress, gear compressive stress and scoring failure are the main concern. In the present study, calculating specifications of the differential planetary gears and analyzing the gear bending and compressive stresses as well as scoring factor of the differential planetary gears gearbox for an optimal design of the mixer gearbox in respect to cost and reliability are investigated. The analyses of actual gear bending and compressive stresses of the differential planetary gears using Lewes & Hertz equation and verifications of the calculated specifications of the differential planetary gears evaluate the results with the data of allowable bending and compressive stress from the Stress-No. of cycles curves of gears. In addition, we also analyze actual gear scoring factor as well as evaluate the possibility of scoring failure of the differential planetary gear.

A leakage-free resonance sparse decomposition technique for bearing fault detection in gearboxes

Science.gov (United States)

Osman, Shazali; Wang, Wilson

2018-03-01

Most of rotating machinery deficiencies are related to defects in rolling element bearings. Reliable bearing fault detection still remains a challenging task, especially for bearings in gearboxes as bearing-defect-related features are nonstationary and modulated by gear mesh vibration. A new leakage-free resonance sparse decomposition (LRSD) technique is proposed in this paper for early bearing fault detection of gearboxes. In the proposed LRSD technique, a leakage-free filter is suggested to remove strong gear mesh and shaft running signatures. A kurtosis and cosine distance measure is suggested to select appropriate redundancy r and quality factor Q. The signal residual is processed by signal sparse decomposition for highpass and lowpass resonance analysis to extract representative features for bearing fault detection. The effectiveness of the proposed technique is verified by a succession of experimental tests corresponding to different gearbox and bearing conditions.

Motor-operated gearbox efficiency

International Nuclear Information System (INIS)

DeWall, K.G.; Watkins, J.C.; Bramwell, D.; Weidenhamer, G.H.

1996-01-01

Researchers at the Idaho National Engineering Laboratory recently conducted tests investigating the operating efficiency of the power train (gearbox) in motor-operators typically used in nuclear power plants to power motor-operated valves. Actual efficiency ratios were determined from in-line measurements of electric motor torque (input to the operator gearbox) and valve stem torque (output from the gearbox) while the operators were subjected to gradually increasing loads until the electric motor stalled. The testing included parametric studies under reduced voltage and elevated temperature conditions. As part of the analysis of the results, the authors compared efficiency values determined from testing to the values published by the operator manufacturer and typically used by the industry in calculations for estimating motor-operator capabilities. The operators they tested under load ran at efficiencies lower than the running efficiency (typically 50%) published by the operator manufacturer

Motor-operated gearbox efficiency

Energy Technology Data Exchange (ETDEWEB)

DeWall, K.G.; Watkins, J.C.; Bramwell, D. [Idaho National Engineering Lab., Idaho Falls, ID (United States); Weidenhamer, G.H.

1996-12-01

Researchers at the Idaho National Engineering Laboratory recently conducted tests investigating the operating efficiency of the power train (gearbox) in motor-operators typically used in nuclear power plants to power motor-operated valves. Actual efficiency ratios were determined from in-line measurements of electric motor torque (input to the operator gearbox) and valve stem torque (output from the gearbox) while the operators were subjected to gradually increasing loads until the electric motor stalled. The testing included parametric studies under reduced voltage and elevated temperature conditions. As part of the analysis of the results, the authors compared efficiency values determined from testing to the values published by the operator manufacturer and typically used by the industry in calculations for estimating motor-operator capabilities. The operators they tested under load ran at efficiencies lower than the running efficiency (typically 50%) published by the operator manufacturer.

Motor-operator gearbox efficiency

International Nuclear Information System (INIS)

DeWall, K.G.; Watkins, J.C.; Bramwell, D.

1996-01-01

Researchers at the Idaho National Engineering Laboratory recently conducted tests investigating the operating efficiency of the power train (gearbox) in motor-operators typically used in nuclear power plants to power motor-operated valves. Actual efficiency ratios were determined from in-line measurements of electric motor torque (input to the operator gearbox) and valve stem torque (output from the gearbox) while the operators were subjected to gradually increasing loads until the electric motor stalled. The testing included parametric studies under reduced voltage and elevated temperature conditions. As part of the analysis of the results, we compared efficiency values determined from testing to the values published by the operator manufacturer and typically used by the industry in calculations for estimating motor-operator capabilities. The operators we tested under load ran at efficiencies lower than the running efficiency (typically 50%) published by the operator manufacturer

Fault detection of gearbox using time-frequency method

Science.gov (United States)

Widodo, A.; Satrijo, Dj.; Prahasto, T.; Haryanto, I.

2017-04-01

This research deals with fault detection and diagnosis of gearbox by using vibration signature. In this work, fault detection and diagnosis are approached by employing time-frequency method, and then the results are compared with cepstrum analysis. Experimental work has been conducted for data acquisition of vibration signal thru self-designed gearbox test rig. This test-rig is able to demonstrate normal and faulty gearbox i.e., wears and tooth breakage. Three accelerometers were used for vibration signal acquisition from gearbox, and optical tachometer was used for shaft rotation speed measurement. The results show that frequency domain analysis using fast-fourier transform was less sensitive to wears and tooth breakage condition. However, the method of short-time fourier transform was able to monitor the faults in gearbox. Wavelet Transform (WT) method also showed good performance in gearbox fault detection using vibration signal after employing time synchronous averaging (TSA).

Conceptual design of planetary gearbox system for constant generator speed in hydro power plant

Directory of Open Access Journals (Sweden)

Bhargav

2018-01-01

Full Text Available Micro Hydro Power Plant (MHPP is emerging as one of the most clean, renewable and reliable energy technology for harnessing power. In MHPP hydro governors are avoided, that results in turbine speed fluctuation. MHPP requires either speed or torque amplification of generator for constant power generation. To achieve this, planetary gear transmission system is explored for MHPP due to its higher efficiency and compact size. A conceptual planetary gearbox system is developed for MHPP to maintain constant generator speed. The conceptual gearbox is designed, modelled and analysed using ADAMS software. Simulation results are found to be in close agreement with analytical results. Hence, conceptual design of planetary gearbox can be used to govern constant generator speed. In this paper, a MHPP which generate constant power of 5 kW at constant generator speed of 1490 rpm is analysed and validated

Dynamic modeling of gearbox faults: A review

Science.gov (United States)

Liang, Xihui; Zuo, Ming J.; Feng, Zhipeng

2018-01-01

Gearbox is widely used in industrial and military applications. Due to high service load, harsh operating conditions or inevitable fatigue, faults may develop in gears. If the gear faults cannot be detected early, the health will continue to degrade, perhaps causing heavy economic loss or even catastrophe. Early fault detection and diagnosis allows properly scheduled shutdowns to prevent catastrophic failure and consequently result in a safer operation and higher cost reduction. Recently, many studies have been done to develop gearbox dynamic models with faults aiming to understand gear fault generation mechanism and then develop effective fault detection and diagnosis methods. This paper focuses on dynamics based gearbox fault modeling, detection and diagnosis. State-of-art and challenges are reviewed and discussed. This detailed literature review limits research results to the following fundamental yet key aspects: gear mesh stiffness evaluation, gearbox damage modeling and fault diagnosis techniques, gearbox transmission path modeling and method validation. In the end, a summary and some research prospects are presented.

Gearbox damage identification and quantification using stochastic resonance

Science.gov (United States)

Mba, Clement U.; Marchesiello, Stefano; Fasana, Alessandro; Garibaldi, Luigi

2018-03-01

Amongst the many new tools used for vibration based mechanical fault diagnosis in rotating machineries, stochastic resonance (SR) has been shown to be able to identify as well as quantify gearbox damage via numerical simulations. To validate the numerical simulation results that were obtained in a previous work by the authors, SR is applied in the present study to data from an experimental gearbox that is representative of an industrial gearbox. Both spur and helical gears are used in the gearbox setup. While the results of the direct application of SR to experimental data do not exactly corroborate the numerical simulation results, applying SR to experimental data in pre-processed form is shown to be quite effective. In addition, it is demonstrated that traditional statistical techniques used for gearbox diagnosis can be used as a reference to check how well SR performs.

Evaluation of wind turbine gearboxes; Evaluering af vindmoellegear

Energy Technology Data Exchange (ETDEWEB)

NONE

2003-08-15

A wind turbine's gearbox is the single component in which failures with risk of breakdown occur. The problems typically occur in the form of pitting damages in cogwheels and breakdown in bearings. The number of gearbox problems are increasing especially in 600 and 750 kW wind turbines. This project comprises a failure detection and analysis system, a gearbox calculation program, load monitoring, and finally dynamics of the mechanical transmission system. (BA)

A Market-Based Analysis on the Main Characteristics of Gearboxes Used in Onshore Wind Turbines

Directory of Open Access Journals (Sweden)

Cristina Vázquez-Hernández

2017-10-01

Full Text Available Even though wind energy is one of the most mature renewable technologies, it is in continuous development not only because of the trend towards larger wind turbines but also because of the development of new technological solutions. The gearbox is one of the components of the drive train in which the industry is concentrating more effort on research and development. Larger rotor blades lead to more demanding requirements for this component as a consequence of a higher mechanical torque and multiplication ratio (due to lower rotational speed of blades while the rotational speed on the generator side remains at similar values. In addition, operating conditions become increasingly demanding in terms of reliability, performance, and compactness. This paper analyses the different gearbox arrangements that are implemented by manufacturers of onshore wind turbines, as well as their market penetration (including different aspects that affect the design of the gearbox, such as drive train configuration and turbine size. The analysis carried out shows a clear convergence towards gearboxes with three stages. However, there is a noticeable diversity in the types of gears used, depending to a large extent on the preferences of each manufacturer but also on the nominal power of the wind turbine and drive train configuration.

Full Life Wind Turbine Gearbox Lubricating Fluids

Energy Technology Data Exchange (ETDEWEB)

Lutz, Glenn A.; Jungk, Manfred; Bryant, Jonathan J.; Lauer, Rebecca S.; Chobot, Anthony; Mayer, Tyler; Palmer, Shane; Kauffman, Robert E.

2012-02-28

using PFPE as the gearbox lubricating fluid. It is important to note the largest portion of savings comes in Levelized Replacement Cost, which is dictated by the assumption on gearbox reliability. Thus, verifying and quantifying the potential of PFPE fluid to effect gearbox reliability is the key assumption that would need to be further validated. In summary the proof of concept to use PFPE fluid as wind turbine gear box lubricant was validated with this project. The increase in life time was qualitatively demonstrated and this supports the need for future activity of field trials and laboratory aging studies to quantify the predicted 20 year life. With micro-pitting being the major failure mechanism in the last years, recent publications show that white etch cracking of bearings seem to have the highest impact on wind turbine reliability. With its higher film thicknesses compared to PAO reference oils, PFPE fluids have the potential to reduce this failure occurrence as well.

Bevel Gearbox Fault Diagnosis using Vibration Measurements

Directory of Open Access Journals (Sweden)

Hartono Dennis

2016-01-01

Full Text Available The use of vibration measurementanalysis has been proven to be effective for gearbox fault diagnosis. However, the complexity of vibration signals observed from a gearbox makes it difficult to accurately detectfaults in the gearbox. This work is based on a comparative studyof several time-frequency signal processing methods that can be used to extract information from transient vibration signals containing useful diagnostic information. Experiments were performed on a bevel gearbox test rig using vibration measurements obtained from accelerometers. Initially, thediscrete wavelet transform was implementedfor vibration signal analysis to extract the frequency content of signal from the relevant frequency region. Several time-frequency signal processing methods werethen incorporated to extract the fault features of vibration signals and their diagnostic performances were compared. It was shown thatthe Short Time Fourier Transform (STFT could not offer a good time resolution to detect the periodicity of the faulty gear tooth due the difficulty in choosing an appropriate window length to capture the impulse signal. The Continuous Wavelet Transform (CWT, on the other hand, was suitable to detection of vibration transients generated by localized fault from a gearbox due to its multi-scale property. However, both methods still require a thorough visual inspection. In contrast, it was shown from the experiments that the diagnostic method using the Cepstrumanalysis could provide a direct indication of the faulty tooth without the need of a thorough visual inspection as required by CWT and STFT.

Economic and Performance Analysis of Gear Box Failures. Cooperative Research and Development Final Report, CRADA Number CRD-07-236

Energy Technology Data Exchange (ETDEWEB)

Keller, Jonathan [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2015-10-01

The National Renewable Energy Laboratory (NREL) in Golden, CO, USA is forming a collaborative within the wind energy industry to address reliability issues on wind turbines. The National Wind Technology Center (NWTC), leading the collaborative effort, will allow gearbox manufacturers, bearing manufacturers, wind turbine owner/operators, and wind turbine manufacturers to team up for joint projects that address specific issues regarding design and reliability of wind turbine gearboxes. The primary means of investigation will be through full scale testing and analysis of actual gearboxes, both in the field and in the NREL 2.5 MW dynamometer test facility. These teams would contribute resources into a campaign that is intended to serve the mutual interests of a majority of the wind and gearbox industry stakeholders in addition to the specific project team objectives. that address specific issues regarding design and reliability of wind turbine gearboxes. The primary means of investigation will be through full scale testing and analysis of actual gearboxes, both in the field and in the NREL 2.5 MW dynamometer test facility. These teams would contribute resources into a campaign that is intended to serve the mutual interests of a majority of the wind and gearbox industry stakeholders in addition to the specific project team objectives.

Vibration Based Diagnosis for Planetary Gearboxes Using an Analytical Model

Directory of Open Access Journals (Sweden)

Liu Hong

2016-01-01

Full Text Available The application of conventional vibration based diagnostic techniques to planetary gearboxes is a challenge because of the complexity of frequency components in the measured spectrum, which is the result of relative motions between the rotary planets and the fixed accelerometer. In practice, since the fault signatures are usually contaminated by noises and vibrations from other mechanical components of gearboxes, the diagnostic efficacy may further deteriorate. Thus, it is essential to develop a novel vibration based scheme to diagnose gear failures for planetary gearboxes. Following a brief literature review, the paper begins with the introduction of an analytical model of planetary gear-sets developed by the authors in previous works, which can predict the distinct behaviors of fault introduced sidebands. This analytical model is easy to implement because the only prerequisite information is the basic geometry of the planetary gear-set. Afterwards, an automated diagnostic scheme is proposed to cope with the challenges associated with the characteristic configuration of planetary gearboxes. The proposed vibration based scheme integrates the analytical model, a denoising algorithm, and frequency domain indicators into one synergistic system for the detection and identification of damaged gear teeth in planetary gearboxes. Its performance is validated with the dynamic simulations and the experimental data from a planetary gearbox test rig.

A Method Based on Multi-Sensor Data Fusion for Fault Detection of Planetary Gearboxes

Directory of Open Access Journals (Sweden)

Detong Kong

2012-02-01

Full Text Available Studies on fault detection and diagnosis of planetary gearboxes are quite limited compared with those of fixed-axis gearboxes. Different from fixed-axis gearboxes, planetary gearboxes exhibit unique behaviors, which invalidate fault diagnosis methods that work well for fixed-axis gearboxes. It is a fact that for systems as complex as planetary gearboxes, multiple sensors mounted on different locations provide complementary information on the health condition of the systems. On this basis, a fault detection method based on multi-sensor data fusion is introduced in this paper. In this method, two features developed for planetary gearboxes are used to characterize the gear health conditions, and an adaptive neuro-fuzzy inference system (ANFIS is utilized to fuse all features from different sensors. In order to demonstrate the effectiveness of the proposed method, experiments are carried out on a planetary gearbox test rig, on which multiple accelerometers are mounted for data collection. The comparisons between the proposed method and the methods based on individual sensors show that the former achieves much higher accuracies in detecting planetary gearbox faults.

Wind Turbine Gearbox Condition Monitoring with AAKR and Moving Window Statistic Methods

OpenAIRE

Peng Guo; Nan Bai

2011-01-01

Condition Monitoring (CM) of wind turbines can greatly reduce the maintenance costs for wind farms, especially for offshore wind farms. A new condition monitoring method for a wind turbine gearbox using temperature trend analysis is proposed. Autoassociative Kernel Regression (AAKR) is used to construct the normal behavior model of the gearbox temperature. With a proper construction of the memory matrix, the AAKR model can cover the normal working space for the gearbox. When the gearbox has a...

Wind Turbine Gearbox Condition Monitoring with AAKR and Moving Window Statistic Methods

Directory of Open Access Journals (Sweden)

Peng Guo

2011-11-01

Full Text Available Condition Monitoring (CM of wind turbines can greatly reduce the maintenance costs for wind farms, especially for offshore wind farms. A new condition monitoring method for a wind turbine gearbox using temperature trend analysis is proposed. Autoassociative Kernel Regression (AAKR is used to construct the normal behavior model of the gearbox temperature. With a proper construction of the memory matrix, the AAKR model can cover the normal working space for the gearbox. When the gearbox has an incipient failure, the residuals between AAKR model estimates and the measurement temperature will become significant. A moving window statistical method is used to detect the changes of the residual mean value and standard deviation in a timely manner. When one of these parameters exceeds predefined thresholds, an incipient failure is flagged. In order to simulate the gearbox fault, manual temperature drift is added to the initial Supervisory Control and Data Acquisitions (SCADA data. Analysis of simulated gearbox failures shows that the new condition monitoring method is effective.

Motor-operated valve (MOV) actuator motor and gearbox testing

International Nuclear Information System (INIS)

DeWall, K.; Watkins, J.C.; Bramwell, D.

1997-07-01

Researchers at the Idaho National Engineering and Environmental Laboratory tested the performance of electric motors and actuator gearboxes typical of the equipment installed on motor-operated valves used in nuclear power plants. Using a test stand that simulates valve closure loads against flow and pressure, the authors tested five electric motors (four ac and one dc) and three gearboxes at conditions a motor might experience in a power plant, including such off-normal conditions as operation at high temperature and reduced voltage. They also monitored the efficiency of the actuator gearbox. All five motors operated at or above their rated starting torque during tests at normal voltages and temperatures. For all five motors, actual torque losses due to voltage degradation were greater than the losses calculated by methods typically used for predicting motor torque at degraded voltage conditions. For the dc motor the actual torque losses due to elevated operating temperatures were greater than the losses calculated by the typical predictive method. The actual efficiencies of the actuator gearboxes were generally lower than the running efficiencies published by the manufacturer and were generally nearer the published pull-out efficiencies. Operation of the gearbox at elevated temperature did not affect the operating efficiency

Vibration condition monitoring of planetary gearbox under varying external load

Energy Technology Data Exchange (ETDEWEB)

Bartelmus, W.; Zimroz, R. [Wroclaw University of Technology, Wroclaw (Poland)

2009-01-15

The paper shows that for condition monitoring of planetary gearboxes it is important to identify the external varying load condition. In the paper, systematic consideration has been taken of the influence of many factors on the vibration signals generated by a system in which a planetary gearbox is included. These considerations give the basis for vibration signal interpretation, development of the means of condition monitoring, and for the scenario of the degradation of the planetary gearbox. Real measured vibration signals obtained in the industrial environment are processed. The signals are recorded during normal operation of the diagnosed objects, namely planetary gearboxes, which are a part of the driving system used in a bucket wheel excavator, used in lignite mines. It has been found that the most important factor of the proper planetary gearbox condition is connected with perturbation of arm rotation, where an arm rotation gives rise to a specific vibration signal whose properties are depicted by a short-time Fourier transform (STFT) and Wigner-Ville distribution presented as a time-frequency map. The paper gives evidence that there are two dominant low-frequency causes that influence vibration signal modulation, i.e. the varying load, which comes from the nature of the bucket wheel digging process, and the arm/carrier rotation. These two causes determine the condition of the planetary gearboxes considered.

Application of Vibration and Oil Analysis for Reliability Information on Helicopter Main Rotor Gearbox

Science.gov (United States)

Murrad, Muhamad; Leong, M. Salman

Based on the experiences of the Malaysian Armed Forces (MAF), failure of the main rotor gearbox (MRGB) was one of the major contributing factors to helicopter breakdowns. Even though vibration and oil analysis are the effective techniques for monitoring the health of helicopter components, these two techniques were rarely combined to form an effective assessment tool in MAF. Results of the oil analysis were often used only for oil changing schedule while assessments of MRGB condition were mainly based on overall vibration readings. A study group was formed and given a mandate to improve the maintenance strategy of S61-A4 helicopter fleet in the MAF. The improvement consisted of a structured approach to the reassessment/redefinition suitable maintenance actions that should be taken for the MRGB. Basic and enhanced tools for condition monitoring (CM) are investigated to address the predominant failures of the MRGB. Quantitative accelerated life testing (QALT) was considered in this work with an intent to obtain the required reliability information in a shorter time with tests under normal stress conditions. These tests when performed correctly can provide valuable information about MRGB performance under normal operating conditions which enable maintenance personnel to make decision more quickly, accurately and economically. The time-to-failure and probability of failure information of the MRGB were generated by applying QALT analysis principles. This study is anticipated to make a dramatic change in its approach to CM, bringing significant savings and various benefits to MAF.

Reliability of wind turbine subassemblies

NARCIS (Netherlands)

Spinato, F.; Tavner, P.J.; Bussel, van G.J.W.; Koutoulakos, E.

2009-01-01

We have investigated the reliability of more than 6000 modern onshore wind turbines and their subassemblies in Denmark and Germany over 11 years and particularly changes in reliability of generators, gearboxes and converters in a subset of 650 turbines in Schleswig Holstein, Germany. We first start

Motor current signature analysis for gearbox condition monitoring under transient speeds using wavelet analysis and dual-level time synchronous averaging

Science.gov (United States)

Bravo-Imaz, Inaki; Davari Ardakani, Hossein; Liu, Zongchang; García-Arribas, Alfredo; Arnaiz, Aitor; Lee, Jay

2017-09-01

This paper focuses on analyzing motor current signature for fault diagnosis of gearboxes operating under transient speed regimes. Two different strategies are evaluated, extensively tested and compared to analyze the motor current signature in order to implement a condition monitoring system for gearboxes in industrial machinery. A specially designed test bench is used, thoroughly monitored to fully characterize the experiments, in which gears in different health status are tested. The measured signals are analyzed using discrete wavelet decomposition, in different decomposition levels using a range of mother wavelets. Moreover, a dual-level time synchronous averaging analysis is performed on the same signal to compare the performance of the two methods. From both analyses, the relevant features of the signals are extracted and cataloged using a self-organizing map, which allows for an easy detection and classification of the diverse health states of the gears. The results demonstrate the effectiveness of both methods for diagnosing gearbox faults. A slightly better performance was observed for dual-level time synchronous averaging method. Based on the obtained results, the proposed methods can used as effective and reliable condition monitoring procedures for gearbox condition monitoring using only motor current signature.

Wind Turbine Gearbox Oil Filtration and Condition Monitoring

Energy Technology Data Exchange (ETDEWEB)

Sheng, Shuangwen

2015-10-25

This is an invited presentation for a pre-conference workshop, titled advances and opportunities in lubrication: wind turbine, at the 2015 Society of Tribologists and Lubrication Engineers (STLE) Tribology Frontiers Conference held in Denver, CO. It gives a brief overview of wind turbine gearbox oil filtration and condition monitoring by highlighting typical industry practices and challenges. The presentation starts with an introduction by covering recent growth of global wind industry, reliability challenges, benefits of oil filtration and condition monitoring, and financial incentives to conduct wind operation and maintenance research, which includes gearbox oil filtration and condition monitoring work presented herein. Then, the presentation moves on to oil filtration by stressing the benefits of filtration, discussing typical main- and offline-loop practices, highlighting important factors considered when specifying a filtration system, and illustrating real-world application challenges through a cold-start example. In the next section on oil condition monitoring, a discussion on oil sample analysis, oil debris monitoring, oil cleanliness measurements and filter analysis is given based on testing results mostly obtained by and at NREL, and by pointing out a few challenges with oil sample analysis. The presentation concludes with a brief touch on future research and development (R and D) opportunities. It is hoping that the information presented can inform the STLE community to start or redirect their R and D work to help the wind industry advance.

Gear-box fault detection using time-frequency based methods

DEFF Research Database (Denmark)

Odgaard, Peter Fogh; Stoustrup, Jakob

2015-01-01

Gear-box fault monitoring and detection is important for optimization of power generation and availability of wind turbines. The current industrial approach is to use condition monitoring systems, which runs in parallel with the wind turbine control system, using expensive additional sensors...... in the gear-box resonance frequency can be detected. Two different time–frequency based approaches are presented in this paper. One is a filter based approach and the other is based on a Karhunen–Loeve basis. Both of them detect the gear-box fault with an acceptable detection delay of maximum 100s, which...... is neglectable compared with the fault developing time....

On damage detection in wind turbine gearboxes using outlier analysis

Science.gov (United States)

Antoniadou, Ifigeneia; Manson, Graeme; Dervilis, Nikolaos; Staszewski, Wieslaw J.; Worden, Keith

2012-04-01

The proportion of worldwide installed wind power in power systems increases over the years as a result of the steadily growing interest in renewable energy sources. Still, the advantages offered by the use of wind power are overshadowed by the high operational and maintenance costs, resulting in the low competitiveness of wind power in the energy market. In order to reduce the costs of corrective maintenance, the application of condition monitoring to gearboxes becomes highly important, since gearboxes are among the wind turbine components with the most frequent failure observations. While condition monitoring of gearboxes in general is common practice, with various methods having been developed over the last few decades, wind turbine gearbox condition monitoring faces a major challenge: the detection of faults under the time-varying load conditions prevailing in wind turbine systems. Classical time and frequency domain methods fail to detect faults under variable load conditions, due to the temporary effect that these faults have on vibration signals. This paper uses the statistical discipline of outlier analysis for the damage detection of gearbox tooth faults. A simplified two-degree-of-freedom gearbox model considering nonlinear backlash, time-periodic mesh stiffness and static transmission error, simulates the vibration signals to be analysed. Local stiffness reduction is used for the simulation of tooth faults and statistical processes determine the existence of intermittencies. The lowest level of fault detection, the threshold value, is considered and the Mahalanobis squared-distance is calculated for the novelty detection problem.

Final Technical Report: Supporting Wind Turbine Research and Testing - Gearbox Durability Study

Energy Technology Data Exchange (ETDEWEB)

Matthew Malkin

2012-04-30

The combination of premature failure of wind turbine gearboxes and the downtime caused by those failures leads to an increase in the cost of electricity produced by the wind. There is a need for guidance to asset managers regarding how to maximize the longevity of their gearboxes in order to help keep the cost of wind energy as low as possible. A low cost of energy supports the US Department of Energy's goal of achieving 20% of the electricity in the United States produced by wind by the year 2030. DNV KEMA has leveraged our unique position in the industry as an independent third party engineering organization to study the problem of gearbox health management and develop guidance to project operators. This report describes the study. The study was conducted in four tasks. In Task 1, data that may be related to gearbox health and are normally available to wind project operators were collected for analysis. Task 2 took a more in-depth look at a small number of gearboxes to gain insight in to relevant failure modes. Task 3 brought together the previous tasks by evaluating the available data in an effort to identify data that could provide early indications of impending gearbox failure. Last, the observations from the work were collected to develop recommendations regarding gearbox health management.

Development of a 5 MW reference gearbox for offshore wind turbines

OpenAIRE

Rasekhi Nejad, Amir; Guo, Yi; Gao, Zhen; Moan, Torgeir

2016-01-01

This paper presents detailed descriptions, modeling parameters and technical data of a 5MW high-speed gearbox developed for the National Renewable Energy Laboratory offshore 5MW baseline wind turbine. The main aim of this paper is to support the concept studies and research for large offshore wind turbines by providing a baseline gearbox model with detailed modeling parameters. This baseline gearbox follows the most conventional design types of those used in wind turbines. It is based on the ...

Lightweight Gearbox Technology, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — To date, the majority of the gearboxes used on the rovers have been based on very conventional materials, process and designs. This has primarily been a result of...

Will the energy crisis put an end to development of automatic gearboxes

Energy Technology Data Exchange (ETDEWEB)

Ward, D

1979-12-13

The power absorbing automatic gearbox may disappear with advancing fuel costs. Electronic controls will be at the center of improvements being developed for possible acceptable small car automatic gearboxes. A total engine management package being developed by Lucas involves extending the microprocessor which with current technology can control both the fuel injection system and the electronic ignition of a car engine to control the automatic gearbox.

Diagnosis of bearing creep in wind turbine gearboxes

DEFF Research Database (Denmark)

Skrimpas, Georgios Alexandros; Liu, Zhenyan; Hilmisson, Reynir

2016-01-01

One of the most wide spread gearbox topologies in the wind energy sector consists of a slow rotating planetary stage, an intermediate speed parallel stage and finally a high speed parallel stage driving the generator rotor. The shafts of the two latter stages are supported by ball or roller...... bearings where their outer races are fixed to the gearbox and their inner races rotate at the corresponding shaft speed. Bearing inner race defects are frequently encountered in gearboxes leading to either replacement of the whole unit or exchange of the shaft or bearing where feasible. The present work...... deals with the evaluation of the development of an inner race defect from surface pitting to race axial crack resulting in excessive rotational looseness, also referred to as bearing creep. It is shown that an inner race defect can be identified efficiently at an early stage by employing well known...

Novel Low Cost, High Reliability Wind Turbine Drivetrain

Energy Technology Data Exchange (ETDEWEB)

Chobot, Anthony; Das, Debarshi; Mayer, Tyler; Markey, Zach; Martinson, Tim; Reeve, Hayden; Attridge, Paul; El-Wardany, Tahany

2012-09-13

Clipper Windpower, in collaboration with United Technologies Research Center, the National Renewable Energy Laboratory, and Hamilton Sundstrand Corporation, developed a low-cost, deflection-compliant, reliable, and serviceable chain drive speed increaser. This chain and sprocket drivetrain design offers significant breakthroughs in the areas of cost and serviceability and addresses the key challenges of current geared and direct-drive systems. The use of gearboxes has proven to be challenging; the large torques and bending loads associated with use in large multi-MW wind applications have generally limited demonstrated lifetime to 8-10 years [1]. The large cost of gearbox replacement and the required use of large, expensive cranes can result in gearbox replacement costs on the order of $1M, representing a significant impact to overall cost of energy (COE). Direct-drive machines eliminate the gearbox, thereby targeting increased reliability and reduced life-cycle cost. However, the slow rotational speeds require very large and costly generators, which also typically have an undesirable dependence on expensive rare-earth magnet materials and large structural penalties for precise air gap control. The cost of rare-earth materials has increased 20X in the last 8 years representing a key risk to ever realizing the promised cost of energy reductions from direct-drive generators. A common challenge to both geared and direct drive architectures is a limited ability to manage input shaft deflections. The proposed Clipper drivetrain is deflection-compliant, insulating later drivetrain stages and generators from off-axis loads. The system is modular, allowing for all key parts to be removed and replaced without the use of a high capacity crane. Finally, the technology modularity allows for scalability and many possible drivetrain topologies. These benefits enable reductions in drivetrain capital cost by 10.0%, levelized replacement and O&M costs by 26.7%, and overall cost of

Vibration analysis of 1 MW gearbox for the Avedoere wind turbine

International Nuclear Information System (INIS)

Crone, A.

1993-08-01

Investigations of the vibrational behaviour of the gearbox for the Avedoere wind turbine, have been carried out by means of test bed measurements. Attention has especially been paid to the structure-borne noise source strength at the frequency of the output gear stage, as tonal gear noise emission from wind turbines, from experience, is dominated by components at this frequency. The structure-borne noise source strength related to the output gear stage of the gearbox has been evaluated and compared for two gear sets with different tooth profile. One is designed by the gear manufacturer, Flender AG, and the other by ELKRAFT A.m.b.A. Vibration measurements at different speeds between 1000 and 2000 rpm showed that the velocity levels at the harmonics of the toothmesth frequencies may change by more than 10 dB in a speed range close to the operational speed. These changes are due to natural vibration modes in the gearbox structure. When resonance conditions between the toothmesh frequency of the output gear stage and torsional modes in the gearbox shaft system may amplify the structure-borne noise generated in the gearbox to an undesirably high level, the natural torsional frequencies of the shaft system have been identified. Comparisons between the identified and calculated natural torsional frequencies show in general a good correlation, with a maximum deviation of 14% between the frequencies. The natural frequencies extracted from the measurements and the torsional calculations, indicate that the structure-borne noise from the gearbox, at the toothmesh frequency of the output gear stage, will not be strongly amplified due to resonance conditions, when the gearbox is operating in the wind turbine at speeds of 1500-1524 rpm. (EG)

Vestas V90-3MW Wind Turbine Gearbox Health Assessment Using a Vibration-Based Condition Monitoring System

Directory of Open Access Journals (Sweden)

A. Romero

2016-01-01

Full Text Available Reliable monitoring for the early fault diagnosis of gearbox faults is of great concern for the wind industry. This paper presents a novel approach for health condition monitoring (CM and fault diagnosis in wind turbine gearboxes using vibration analysis. This methodology is based on a machine learning algorithm that generates a baseline for the identification of deviations from the normal operation conditions of the turbine and the intrinsic characteristic-scale decomposition (ICD method for fault type recognition. Outliers picked up during the baseline stage are decomposed by the ICD method to obtain the product components which reveal the fault information. The new methodology proposed for gear and bearing defect identification was validated by laboratory and field trials, comparing well with the methods reviewed in the literature.

Diagnostic Analyzer for Gearboxes (DAG): User's Guide. Version 3.1 for Microsoft Windows 3.1

Science.gov (United States)

Jammu, Vinay B.; Kourosh, Danai

1997-01-01

This documentation describes the Diagnostic Analyzer for Gearboxes (DAG) software for performing fault diagnosis of gearboxes. First, the user would construct a graphical representation of the gearbox using the gear, bearing, shaft, and sensor tools contained in the DAG software. Next, a set of vibration features obtained by processing the vibration signals recorded from the gearbox using a signal analyzer is required. Given this information, the DAG software uses an unsupervised neural network referred to as the Fault Detection Network (FDN) to identify the occurrence of faults, and a pattern classifier called Single Category-Based Classifier (SCBC) for abnormality scaling of individual vibration features. The abnormality-scaled vibration features are then used as inputs to a Structure-Based Connectionist Network (SBCN) for identifying faults in gearbox subsystems and components. The weights of the SBCN represent its diagnostic knowledge and are derived from the structure of the gearbox graphically presented in DAG. The outputs of SBCN are fault possibility values between 0 and 1 for individual subsystems and components in the gearbox with a 1 representing a definite fault and a 0 representing normality. This manual describes the steps involved in creating the diagnostic gearbox model, along with the options and analysis tools of the DAG software.

Feature Mining and Health Assessment for Gearboxes Using Run-Up/Coast-Down Signals

Science.gov (United States)

Zhao, Ming; Lin, Jing; Miao, Yonghao; Xu, Xiaoqiang

2016-01-01

Vibration signals measured in the run-up/coast-down (R/C) processes usually carry rich information about the health status of machinery. However, a major challenge in R/C signals analysis lies in how to exploit more diagnostic information, and how this information could be properly integrated to achieve a more reliable maintenance decision. Aiming at this problem, a framework of R/C signals analysis is presented for the health assessment of gearbox. In the proposed methodology, we first investigate the data preprocessing and feature selection issues for R/C signals. Based on that, a sparsity-guided feature enhancement scheme is then proposed to extract the weak phase jitter associated with gear defect. In order for an effective feature mining and integration under R/C, a generalized phase demodulation technique is further established to reveal the evolution of modulation feature with operating speed and rotation angle. The experimental results indicate that the proposed methodology could not only detect the presence of gear damage, but also offer a novel insight into the dynamic behavior of gearbox. PMID:27827831

Monitoring of Wind Turbine Gearbox Condition through Oil and Wear Debris Analysis: A Full-Scale Testing Perspective

Energy Technology Data Exchange (ETDEWEB)

Sheng, Shuangwen

2016-10-01

Despite the wind industry's dramatic development during the past decade, it is still challenged by premature turbine subsystem/component failures, especially for turbines rated above 1 MW. Because a crane is needed for each replacement, gearboxes have been a focal point for improvement in reliability and availability. Condition monitoring (CM) is a technique that can help improve these factors, leading to reduced turbine operation and maintenance costs and, subsequently, lower cost of energy for wind power. Although technical benefits of CM for the wind industry are normally recognized, there is a lack of published information on the advantages and limitations of each CM technique confirmed by objective data from full-scale tests. This article presents first-hand oil and wear debris analysis results obtained through tests that were based on full-scale wind turbine gearboxes rated at 750 kW. The tests were conducted at the 2.5-MW dynamometer test facility at the National Wind Technology Center at the National Renewable Energy Laboratory. The gearboxes were tested in three conditions: run-in, healthy, and damaged. The investigated CM techniques include real-time oil condition and wear debris monitoring, both inline and online sensors, and offline oil sample and wear debris analysis, both onsite and offsite laboratories. The reported results and observations help increase wind industry awareness of the benefits and limitations of oil and debris analysis technologies and highlight the challenges in these technologies and other tribological fields for the Society of Tribologists and Lubrication Engineers and other organizations to help address, leading to extended gearbox service life.

Health condition identification of multi-stage planetary gearboxes using a mRVM-based method

Science.gov (United States)

Lei, Yaguo; Liu, Zongyao; Wu, Xionghui; Li, Naipeng; Chen, Wu; Lin, Jing

2015-08-01

Multi-stage planetary gearboxes are widely applied in aerospace, automotive and heavy industries. Their key components, such as gears and bearings, can easily suffer from damage due to tough working environment. Health condition identification of planetary gearboxes aims to prevent accidents and save costs. This paper proposes a method based on multiclass relevance vector machine (mRVM) to identify health condition of multi-stage planetary gearboxes. In this method, a mRVM algorithm is adopted as a classifier, and two features, i.e. accumulative amplitudes of carrier orders (AACO) and energy ratio based on difference spectra (ERDS), are used as the input of the classifier to classify different health conditions of multi-stage planetary gearboxes. To test the proposed method, seven health conditions of a two-stage planetary gearbox are considered and vibration data is acquired from the planetary gearbox under different motor speeds and loading conditions. The results of three tests based on different data show that the proposed method obtains an improved identification performance and robustness compared with the existing method.

Vibration Analysis and Time Series Prediction for Wind Turbine Gearbox Prognostics

Directory of Open Access Journals (Sweden)

Hossam A. Gabbar

2013-01-01

Full Text Available Premature failure of a gearbox in a wind turbine poses a high risk of increasing the operational and maintenance costs and decreasing the profit margins. Prognostics and health management (PHM techniques are widely used to access the current health condition of the gearbox and project it in future to predict premature failures. This paper proposes such techniques for predicting gearbox health condition index extracted from the vibration signals emanating from the gearbox. The progression of the monitoring index is predicted using two different prediction techniques, adaptive neuro-fuzzy inference system (ANFIS and nonlinear autoregressive model with exogenous inputs (NARX. The proposed prediction techniques are evaluated through sun-spot data-set and applied on vibration based health related monitoring index calculated through psychoacoustic phenomenon. A comparison is given for their prediction accuracy. The results are helpful in understanding the relationship of machine conditions, the corresponding indicating features, the level of damage/degradation, and their progression.

Planetary Load Sharing in Three-Point Mounted Wind Turbine Gearboxes: A Design and Test Comparison

Energy Technology Data Exchange (ETDEWEB)

Keller, Jonathan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Guo, Yi [National Renewable Energy Lab. (NREL), Golden, CO (United States); Zhang, Zhiwei [Romax InSight, Nottingham, (United Kingdom); Lucas, Doug [The Timken Company, Jackson Township, OH (United States)

2017-04-06

This work compares the planetary load-sharing characteristics of wind turbine gearboxes supported by cylindrical roller bearings (CRBs) and preloaded tapered roller bearings (TRBs) when subjected to rotor moments. Planetary bearing loads were measured in field-representative dynamometer tests and compared to loads predicted by finite-element models. Preloaded TRBs significantly improved load sharing. In pure torque conditions, the upwind planet bearing load in the gearbox with preloaded TRBs was only 14% more than the assumed load compared to 47% more for the gearbox with CRBs. Consequently, the predicted fatigue life of the complete set of planetary bearings for the gearbox with preloaded TRBs is 3.5 times greater than that of the gearbox with CRBs.

MOV motor and gearbox performance under design basis loads

International Nuclear Information System (INIS)

DeWall, K.G.; Watkins, J.C.

1998-01-01

This paper describes the results of valve testing sponsored by the US Nuclear Regulatory Commission, Office of Nuclear Regulatory Research and conducted at the Idaho National Engineering and Environmental Laboratory. The research objective was to evaluate the capabilities of specific actuator motor and gearbox assemblies under various design basis loading conditions. The testing was performed using the motor-operated valve load simulator, a test fixture that simulates the stem load profiles a valve actuator would experience when closing a valve against flow and pressure loadings. The authors tested five typical motors (four ac motors and one dc motor) with three gearbox assemblies at conditions a motor might experience in a power plant, including such off-normal conditions as operation at high temperature and reduced voltage. The authors also determined the efficiency of the actuator gearbox. The testing produced the following significant results: all five motors operated at or above their rated torque during tests at full voltage and ambient temperature; for all five motors (dc as well as ac), the actual torque loss due to voltage degradation was greater than the torque loss predicted using common methods; startup torques in locked rotor tests compared well with stall torques in dynamometer-type tests; the methods commonly used to predict torque losses due to elevated operating temperatures sometimes bounded the actual losses, but not in all cases; the greatest discrepancy involved the prediction for the dc motor; running efficiencies published by the manufacturer for actuator gearboxes were higher than the actual efficiencies determined from testing, in some instances, the published pullout efficiencies were also higher than the actual values; operation of the gearbox at elevated temperature did not affect the operating efficiency

Vibration-based Fault Diagnostic of a Spur Gearbox

Directory of Open Access Journals (Sweden)

Hartono Dennis

2016-01-01

Full Text Available This paper presents comparative studies of Fast Fourier Transform (FFT, Short Time Fourier Transform (STFT and Continuous Wavelet Transform (CWT as several advanced time-frequency analysis methods for diagnosing an early stage of spur gear tooth failure. An incipient fault of a chipped tooth was investigated in this work using vibration measurements from a spur gearbox test rig. Time Synchronous Averaging was implemented for the analysis to enhance the clarity of fault feature from the gear of interest. Based on the experimental results and analysis, it was shown that FFT method could identify the location of the faulty gear with sufficient accuracy. On the other hand, Short Time Fourier Transform method could not provide the angular location information of the faulty gear. It was found that the Continuous Wavelet Transform method offered the best representation of angle-frequency representation. It was not only able to distinguish the difference between the normal and faulty gearboxes from the joint angle-frequency results but could also provide an accurate angular location of the faulty gear tooth in the gearbox.

Gearbox Vibration Signal Amplitude and Frequency Modulation

Directory of Open Access Journals (Sweden)

Fakher Chaari

2012-01-01

Full Text Available Gearboxes usually run under fluctuating load conditions during service, however most of papers available in the literature describe models of gearboxes under stationary load conditions. Main task of published papers is fault modeling for their detection. Considering real situation from industry, the assumption of stationarity of load conditions cannot be longer kept. Vibration signals issued from monitoring in maintenance operations differ from mentioned models (due to load non-stationarity and may be difficult to analyze which lead to erroneous diagnosis of the system. The objective of this paper is to study the influence of time varying load conditions on a gearbox dynamic behavior. To investigate this, a simple spur gear system without defects is modeled. It is subjected to a time varying load. The speed-torque characteristic of the driving motor is considered. The load variation induces speed variation, which causes a variation in the gearmesh stiffness period. Computer simulation shows deep amplitude modulations with sidebands that don't differ from those obtained when there is a defective tooth. In order to put in evidence the time varying load effects, Short Time Fourier Transform and then Smoothed Wigner-Ville distribution are used. Results show that the last one is well suited for the studied case.

Karhunen Loeve Basis Used for Detection of Gearbox Faults in a Wind Turbine

DEFF Research Database (Denmark)

Odgaard, Peter Fogh; Stoustrup, Jakob

2014-01-01

Reliability and sustainability of wind turbines increase in importance as wind turbines contribute with increasing power generation to the world's power grids. One possible way to achieve this is by using advanced fault detection and isolation methods in wind turbines based on the measurements...... provided to the control system. In this paper a Karhunen-Loeve basis approach is designed for detecting changes in frequency response from rotating parts like a gearbox. The potential of this method is shown by applying it to an established Wind Turbine FDI and FTC Benchmark model. These faults...

Influence of flexible pin for planets on service life of wind turbine gearboxes

International Nuclear Information System (INIS)

Park, Young Jun; Lee, Geun Ho; Nam, Yong Yun; Kim, Jeong Kil

2012-01-01

An overhung mounted carrier with flexible pins is applied to the planetary gear train of a wind turbine gearbox to investigate the influence of the self aligning effect by means of the deflection of the planet spindle and the flexible pin on the lifetime of the planet gear for a wind turbine gearbox. To analyze the load distribution of planet gears, both Euler theory and commercial software are employed. By applying an overhung mounted carrier with flexible pins in the wind turbine gearbox, we can improve the misalignment performance, face load factor, and service life of the planet gears. In particular, it was confirmed that a service life of more than 20 years could be realized for wind turbine gearboxes by applying a flexible pin to overhung mounted carrier

Final assessment of vibro-acoustic source strength descriptors of helicopter gearboxes

DEFF Research Database (Denmark)

Ohlrich, Mogens; Rasmussen, Ulrik Møller

1996-01-01

Two novel measurement techniques have been developed for quantifying the vibro-aqcoustic source strength of lightweight helicopter gearboxes. The accuracy, robustness and implementation of these methods have been examined by a comprehensive investigation, including theoretical studies of simple...... multi-modal beam systems and extensive experiments with more realistic small scale models and with large, detailed 3/4-scale test structures of a medium-size helicopter. In addition, partial verification tests have been conducted with the Eurocopter BK 117 helicopter and its main rotor gearbox....... The results of this work are essential as input for any prediction code of the internal noise in a helicopter cabin, because the prediction requires knowledge of the major sources, that is, the rotors, engines and gearboxes....

Gearbox Fault Features Extraction Using Vibration Measurements and Novel Adaptive Filtering Scheme

Directory of Open Access Journals (Sweden)

Ghalib R. Ibrahim

2012-01-01

Full Text Available Vibration signals measured from a gearbox are complex multicomponent signals, generated by tooth meshing, gear shaft rotation, gearbox resonance vibration signatures, and a substantial amount of noise. This paper presents a novel scheme for extracting gearbox fault features using adaptive filtering techniques for enhancing condition features, meshing frequency sidebands. A modified least mean square (LMS algorithm is examined and validated using only one accelerometer, instead of using two accelerometers in traditional arrangement, as the main signal and a desired signal is artificially generated from the measured shaft speed and gear meshing frequencies. The proposed scheme is applied to a signal simulated from gearbox frequencies with a numerous values of step size. Findings confirm that 10−5 step size invariably produces more accurate results and there has been a substantial improvement in signal clarity (better signal-to-noise ratio, which makes meshing frequency sidebands more discernible. The developed scheme is validated via a number of experiments carried out using two-stage helical gearbox for a healthy pair of gears and a pair suffering from a tooth breakage with severity fault 1 (25% tooth removal and fault 2 (50% tooth removal under loads (0%, and 80% of the total load. The experimental results show remarkable improvements and enhance gear condition features. This paper illustrates that the new approach offers a more effective way to detect early faults.

Gearbox tooth cut fault diagnostics using acoustic emission and vibration sensors--a comparative study.

Science.gov (United States)

Qu, Yongzhi; He, David; Yoon, Jae; Van Hecke, Brandon; Bechhoefer, Eric; Zhu, Junda

2014-01-14

In recent years, acoustic emission (AE) sensors and AE-based techniques have been developed and tested for gearbox fault diagnosis. In general, AE-based techniques require much higher sampling rates than vibration analysis-based techniques for gearbox fault diagnosis. Therefore, it is questionable whether an AE-based technique would give a better or at least the same performance as the vibration analysis-based techniques using the same sampling rate. To answer the question, this paper presents a comparative study for gearbox tooth damage level diagnostics using AE and vibration measurements, the first known attempt to compare the gearbox fault diagnostic performance of AE- and vibration analysis-based approaches using the same sampling rate. Partial tooth cut faults are seeded in a gearbox test rig and experimentally tested in a laboratory. Results have shown that the AE-based approach has the potential to differentiate gear tooth damage levels in comparison with the vibration-based approach. While vibration signals are easily affected by mechanical resonance, the AE signals show more stable performance.

A new nonlinear blind source separation method with chaos indicators for decoupling diagnosis of hybrid failures: A marine propulsion gearbox case with a large speed variation

International Nuclear Information System (INIS)

Li, Zhixiong; Peng, Z

2016-01-01

The normal operation of propulsion gearboxes ensures the ship safety. Chaos indicators could efficiently indicate the state change of the gearboxes. However, accurate detection of gearbox hybrid faults using Chaos indicators is a challenging task and the detection under speed variation conditions is attracting considerable attentions. Literature review suggests that the gearbox vibration is a kind of nonlinear mixture of variant vibration sources and the blind source separation (BSS) is reported to be a promising technique for fault vibration analysis, but very limited work has addressed the nonlinear BSS approach for hybrid faults decoupling diagnosis. Aiming to enhance the fault detection performance of Chaos indicators, this work presents a new nonlinear BSS algorithm for gearbox hybrid faults detection under a speed variation condition. This new method appropriately introduces the kernel spectral regression (KSR) framework into the morphological component analysis (MCA). The original vibration data are projected into the reproducing kernel Hilbert space (RKHS) where the instinct nonlinear structure in the original data can be linearized by KSR. Thus the MCA is able to deal with nonlinear BSS in the KSR space. Reliable hybrid faults decoupling is then achieved by this new nonlinear MCA (NMCA). Subsequently, by calculating the Chaos indicators of the decoupled fault components and comparing them with benchmarks, the hybrid faults can be precisely identified. Two specially designed case studies were implemented to evaluate the proposed NMCA-Chaos method on hybrid gear faults decoupling diagnosis. The performance of the NMCA-Chaos was compared with state of art techniques. The analysis results show high performance of the proposed method on hybrid faults detection in a marine propulsion gearbox with large speed variations.

Motor-gearbox selection for energy efficiency

NARCIS (Netherlands)

Dresscher, Douwe; de Vries, Theodorus J.A.; Stramigioli, Stefano

Energy consumption of robotic systems is getting more and more attention. Previous work suggests that energy losses in the actuators of robots are a significant source of high energy consumption. A possible reason is that, so far, motor-gearbox selection methods have not focussed on energy

Integrated Approach Using Condition Monitoring and Modeling to Investigate Wind Turbine Gearbox Design: Preprint

Energy Technology Data Exchange (ETDEWEB)

Sheng, S.; Guo, Y.

2015-03-01

Vibration-based condition monitoring (CM) of geared utility-scale turbine drivetrains has been used by the wind industry to help improve operation and maintenance (O&M) practices, increase turbine availability, and reduce O&M cost. This study is a new endeavor that integrates the vibration-based CM technique with wind turbine gearbox modeling to investigate various gearbox design options. A teamof researchers performed vibration-based CM measurements on a damaged wind turbine gearbox with a classic configuration, (i.e., one planetary stage and two parallel stages). We observed that the acceleration amplitudes around the first-order sidebands of the intermediate stage gear set meshing frequency were much lower than that measured at the high-speed gear set, and similar difference wasalso observed in a healthy gearbox. One factor for a reduction at the intermediate stage gear set is hypothesized to be the soft sun-spline configuration in the test gearbox. To evaluate this hypothesis, a multibody dynamic model of the healthy test gearbox was first developed and validated. Relative percent difference of the first-order sidebands--of the high-speed and intermediate stagegear-meshing frequencies--in the soft and the rigid sun spline configurations were compared. The results verified that the soft sun-spline configuration can reduce the sidebands of the intermediate stage gear set and also the locating bearing loads. The study demonstrates that combining vibration-based CM with appropriate modeling can provide insights for evaluating different wind turbinegearbox design options.

Gearbox fault diagnosis based on deep random forest fusion of acoustic and vibratory signals

Science.gov (United States)

Li, Chuan; Sanchez, René-Vinicio; Zurita, Grover; Cerrada, Mariela; Cabrera, Diego; Vásquez, Rafael E.

2016-08-01

Fault diagnosis is an effective tool to guarantee safe operations in gearboxes. Acoustic and vibratory measurements in such mechanical devices are all sensitive to the existence of faults. This work addresses the use of a deep random forest fusion (DRFF) technique to improve fault diagnosis performance for gearboxes by using measurements of an acoustic emission (AE) sensor and an accelerometer that are used for monitoring the gearbox condition simultaneously. The statistical parameters of the wavelet packet transform (WPT) are first produced from the AE signal and the vibratory signal, respectively. Two deep Boltzmann machines (DBMs) are then developed for deep representations of the WPT statistical parameters. A random forest is finally suggested to fuse the outputs of the two DBMs as the integrated DRFF model. The proposed DRFF technique is evaluated using gearbox fault diagnosis experiments under different operational conditions, and achieves 97.68% of the classification rate for 11 different condition patterns. Compared to other peer algorithms, the addressed method exhibits the best performance. The results indicate that the deep learning fusion of acoustic and vibratory signals may improve fault diagnosis capabilities for gearboxes.

Recommendations on Model Fidelity for Wind Turbine Gearbox Simulations: Preprint

Energy Technology Data Exchange (ETDEWEB)

Guo, Y.; Keller, J.; La Cava, W.; Austin, J.; Nejad, A. R.; Halse, C.; Bastard, L.; Helsen, J.

2015-01-01

This work investigates the minimum level of fidelity required to accurately simulate wind turbine gearboxes using state-of-the-art design tools. Excessive model fidelity including drivetrain complexity, gearbox complexity, excitation sources, and imperfections, significantly increases computational time, but may not provide a commensurate increase in the value of the results. Essential design parameters are evaluated, including the planetary load-sharing factor, gear tooth load distribution, and sun orbit motion. Based on the sensitivity study results, recommendations for the minimum model fidelities are provided.

Gearbox Tooth Cut Fault Diagnostics Using Acoustic Emission and Vibration Sensors — A Comparative Study

Directory of Open Access Journals (Sweden)

Yongzhi Qu

2014-01-01

Full Text Available In recent years, acoustic emission (AE sensors and AE-based techniques have been developed and tested for gearbox fault diagnosis. In general, AE-based techniques require much higher sampling rates than vibration analysis-based techniques for gearbox fault diagnosis. Therefore, it is questionable whether an AE-based technique would give a better or at least the same performance as the vibration analysis-based techniques using the same sampling rate. To answer the question, this paper presents a comparative study for gearbox tooth damage level diagnostics using AE and vibration measurements, the first known attempt to compare the gearbox fault diagnostic performance of AE- and vibration analysis-based approaches using the same sampling rate. Partial tooth cut faults are seeded in a gearbox test rig and experimentally tested in a laboratory. Results have shown that the AE-based approach has the potential to differentiate gear tooth damage levels in comparison with the vibration-based approach. While vibration signals are easily affected by mechanical resonance, the AE signals show more stable performance.

Gearbox Tooth Cut Fault Diagnostics Using Acoustic Emission and Vibration Sensors — A Comparative Study

Science.gov (United States)

Qu, Yongzhi; He, David; Yoon, Jae; Van Hecke, Brandon; Bechhoefer, Eric; Zhu, Junda

2014-01-01

In recent years, acoustic emission (AE) sensors and AE-based techniques have been developed and tested for gearbox fault diagnosis. In general, AE-based techniques require much higher sampling rates than vibration analysis-based techniques for gearbox fault diagnosis. Therefore, it is questionable whether an AE-based technique would give a better or at least the same performance as the vibration analysis-based techniques using the same sampling rate. To answer the question, this paper presents a comparative study for gearbox tooth damage level diagnostics using AE and vibration measurements, the first known attempt to compare the gearbox fault diagnostic performance of AE- and vibration analysis-based approaches using the same sampling rate. Partial tooth cut faults are seeded in a gearbox test rig and experimentally tested in a laboratory. Results have shown that the AE-based approach has the potential to differentiate gear tooth damage levels in comparison with the vibration-based approach. While vibration signals are easily affected by mechanical resonance, the AE signals show more stable performance. PMID:24424467

ANALYSIS OF THE POSSIBILITY OF INTEGRATING A MINING RIGHT-ANGLE PLANETARY GEARBOX WITH TECHNICAL DIAGNOSTICS SYSTEMS

Directory of Open Access Journals (Sweden)

Andrzej WIECZOREK

2016-12-01

Full Text Available A key factor enabling the achievement of the required capacity by longwall mining systems is to obtain a satisfactory service life for individual components of such systems. Such components include right-angle planetary gearboxes for armoured face conveyors. An increase in the service life of such equipment can be achieved by ensuring adequacy in terms of design, materials and organization. As a part of organizational changes, the use of individual diagnostics systems may have the greatest impact on the service life of mining gearboxes; however, their widespread implementation is limited by economic and operational barriers. This paper presents an analysis of the possibility of integrating mining gearboxes with electronic systems of technical diagnostics, as well as expanding the scope of the technical condition monitoring by the machines operating together with these gearboxes. As a result of the calculation and design work performed, it has been demonstrated that it is possible to integrate technical diagnostics systems with advanced data transmission capabilities inside gearboxes.

The study about planetary gearbox virtual prototyping with nonlinear gear contact characteristics

International Nuclear Information System (INIS)

Yin Huabing; Zhou Guangming

2010-01-01

. It solves the difficulty of gear contact simulation in multi-body dynamic model and provides a new method in gear mesh stiffness calculation, which exports simulationX (or other software) model of nonlinear gear stiffness to replace that in multi-body dynamic model and succeeds in integrating planetary gear transmission with other parts of the vehicle. According to the simulation results, the conclusion can be made that the nonlinear modelling method for planetary gearbox is reliable and practical. It can be used to evaluate vibration characteristic of planetary gear transmission with high speed input

Simultaneous-Fault Diagnosis of Gearboxes Using Probabilistic Committee Machine

Science.gov (United States)

Zhong, Jian-Hua; Wong, Pak Kin; Yang, Zhi-Xin

2016-01-01

This study combines signal de-noising, feature extraction, two pairwise-coupled relevance vector machines (PCRVMs) and particle swarm optimization (PSO) for parameter optimization to form an intelligent diagnostic framework for gearbox fault detection. Firstly, the noises of sensor signals are de-noised by using the wavelet threshold method to lower the noise level. Then, the Hilbert-Huang transform (HHT) and energy pattern calculation are applied to extract the fault features from de-noised signals. After that, an eleven-dimension vector, which consists of the energies of nine intrinsic mode functions (IMFs), maximum value of HHT marginal spectrum and its corresponding frequency component, is obtained to represent the features of each gearbox fault. The two PCRVMs serve as two different fault detection committee members, and they are trained by using vibration and sound signals, respectively. The individual diagnostic result from each committee member is then combined by applying a new probabilistic ensemble method, which can improve the overall diagnostic accuracy and increase the number of detectable faults as compared to individual classifiers acting alone. The effectiveness of the proposed framework is experimentally verified by using test cases. The experimental results show the proposed framework is superior to existing single classifiers in terms of diagnostic accuracies for both single- and simultaneous-faults in the gearbox. PMID:26848665

Ultimate design load analysis of planetary gearbox bearings under extreme events

DEFF Research Database (Denmark)

Gallego Calderon, Juan Felipe; Natarajan, Anand; Cutululis, Nicolaos Antonio

2017-01-01

This paper investigates the impact of extreme events on the planet bearings of a 5 MW gearbox. The system is simulated using an aeroelastic tool, where the turbine structure is modeled, and MATLAB/Simulink, where the drivetrain (gearbox and generator) are modeled using a lumped-parameter approach....... Three extreme events are assessed: low-voltage ride through, emergency stop and normal stop. The analysis is focused on finding which event has the most negative impact on the bearing extreme radial loads. The two latter events are carried out following the guidelines of the International...

Multiple-Fault Detection Methodology Based on Vibration and Current Analysis Applied to Bearings in Induction Motors and Gearboxes on the Kinematic Chain

Directory of Open Access Journals (Sweden)

Juan Jose Saucedo-Dorantes

2016-01-01

Full Text Available Gearboxes and induction motors are important components in industrial applications and their monitoring condition is critical in the industrial sector so as to reduce costs and maintenance downtimes. There are several techniques associated with the fault diagnosis in rotating machinery; however, vibration and stator currents analysis are commonly used due to their proven reliability. Indeed, vibration and current analysis provide fault condition information by means of the fault-related spectral component identification. This work presents a methodology based on vibration and current analysis for the diagnosis of wear in a gearbox and the detection of bearing defect in an induction motor both linked to the same kinematic chain; besides, the location of the fault-related components for analysis is supported by the corresponding theoretical models. The theoretical models are based on calculation of characteristic gearbox and bearings fault frequencies, in order to locate the spectral components of the faults. In this work, the influence of vibrations over the system is observed by performing motor current signal analysis to detect the presence of faults. The obtained results show the feasibility of detecting multiple faults in a kinematic chain, making the proposed methodology suitable to be used in the application of industrial machinery diagnosis.

Part-turn gearboxes for electric actuators; Schwenkgetriebe fuer elektrische Stellantriebe

Energy Technology Data Exchange (ETDEWEB)

Herbstritt, M. [Riester (W.) GmbH und Co. KG, Muellheim (Germany)

2002-09-01

Different types of gearboxes provide a useful complement to the electric actuator type ranges. The gearboxes can be combined with the actuators in many ways. Multi-turn actuators, for example, can be turned into part-turn actuators. When using a modular system, a suitable solution for almost any automation task in the field of industrial valves can be found. (orig.) [German] Sinnvoll ergaenzt werden elektrische Stellantriebe fuer Armaturen durch verschiedene Arten von Getrieben. Die Getriebe sind in vielfaeltiger Weise mit den Stellantrieben kombinierbar. So werden beispielsweise aus Drehantrieben Schwenkantriebe. Mit einem Baukasten-System laesst sich so fuer nahezu jede Automatisierungsaufgabe im Bereich der Industriearmaturen eine passende Loesung finden. (orig.)

Design, development and test of the gearbox condition monitoring system using sound signal processing

Directory of Open Access Journals (Sweden)

M Zamani

2016-09-01

Full Text Available Introduction One of the ways used for minimizing the cost of maintenance and repairs of rotating industrial equipment is condition monitoring using acoustic analysis. One of the most important problems which always have been under consideration in industrial equipment application is confidence possibility. Each dynamic, electrical, hydraulic or thermal system has certain characteristics which show the normal condition of the machine during function. Any changes of the characteristics can be a signal of a problem in the machine. The aim of condition monitoring is system condition determination using measurements of the signals of characteristics and using this information for system impairment prognostication. There are a lot of ways for condition monitoring of different systems, but sound analysis is accepted and used extensively as a method for condition investigation of rotating machines. The aim of this research is the design and construction of considered gearbox and using of obtaining data in frequency and time spectrum in order to analyze the sound and diagnosis. Materials and Methods This research was conducted at the department of mechanical biosystem workshop at Aboureihan College at Tehran University in February 15th.2015. In this research, in order to investigate the trend of diagnosis and gearbox condition, a system was designed and then constructed. The sound of correct and damaged gearbox was investigated by audiometer and stored in computer for data analysis. Sound measurement was done in three pinions speed of 749, 1050 and 1496 rpm and for correct gearboxes, damage of the fracture of a tooth and a tooth wear. Gearbox design and construction: In order to conduct the research, a gearbox with simple gearwheels was designed according to current needs. Then mentioned gearbox and its accessories were modeled in CATIA V5-R20 software and then the system was constructed. Gearbox is a machine that is used for mechanical power transition

A novel vibration-based fault diagnostic algorithm for gearboxes under speed fluctuations without rotational speed measurement

Science.gov (United States)

Hong, Liu; Qu, Yongzhi; Dhupia, Jaspreet Singh; Sheng, Shuangwen; Tan, Yuegang; Zhou, Zude

2017-09-01

The localized failures of gears introduce cyclic-transient impulses in the measured gearbox vibration signals. These impulses are usually identified from the sidebands around gear-mesh harmonics through the spectral analysis of cyclo-stationary signals. However, in practice, several high-powered applications of gearboxes like wind turbines are intrinsically characterized by nonstationary processes that blur the measured vibration spectra of a gearbox and deteriorate the efficacy of spectral diagnostic methods. Although order-tracking techniques have been proposed to improve the performance of spectral diagnosis for nonstationary signals measured in such applications, the required hardware for the measurement of rotational speed of these machines is often unavailable in industrial settings. Moreover, existing tacho-less order-tracking approaches are usually limited by the high time-frequency resolution requirement, which is a prerequisite for the precise estimation of the instantaneous frequency. To address such issues, a novel fault-signature enhancement algorithm is proposed that can alleviate the spectral smearing without the need of rotational speed measurement. This proposed tacho-less diagnostic technique resamples the measured acceleration signal of the gearbox based on the optimal warping path evaluated from the fast dynamic time-warping algorithm, which aligns a filtered shaft rotational harmonic signal with respect to a reference signal assuming a constant shaft rotational speed estimated from the approximation of operational speed. The effectiveness of this method is validated using both simulated signals from a fixed-axis gear pair under nonstationary conditions and experimental measurements from a 750-kW planetary wind turbine gearbox on a dynamometer test rig. The results demonstrate that the proposed algorithm can identify fault information from typical gearbox vibration measurements carried out in a resource-constrained industrial environment.

Improving Wind Turbine Drivetrain Reliability Using a Combined Experimental, Computational, and Analytical Approach

Energy Technology Data Exchange (ETDEWEB)

Guo, Y.; van Dam, J.; Bergua, R.; Jove, J.; Campbell, J.

2015-03-01

Nontorque loads induced by the wind turbine rotor overhang weight and aerodynamic forces can greatly affect drivetrain loads and responses. If not addressed properly, these loads can result in a decrease in gearbox component life. This work uses analytical modeling, computational modeling, and experimental data to evaluate a unique drivetrain design that minimizes the effects of nontorque loads on gearbox reliability: the Pure Torque(R) drivetrain developed by Alstom. The drivetrain has a hub-support configuration that transmits nontorque loads directly into the tower rather than through the gearbox as in other design approaches. An analytical model of Alstom's Pure Torque drivetrain provides insight into the relationships among turbine component weights, aerodynamic forces, and the resulting drivetrain loads. Main shaft bending loads are orders of magnitude lower than the rated torque and are hardly affected by wind conditions and turbine operations.

Wind Turbine Drivetrain Reliability Collaborative Workshop: A Recap

Energy Technology Data Exchange (ETDEWEB)

Keller, Jonathan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sheng, Shuangwen [National Renewable Energy Lab. (NREL), Golden, CO (United States); Cotrell, Jason [National Renewable Energy Lab. (NREL), Golden, CO (United States); Greco, Aaron [Argonne National Lab. (ANL), Argonne, IL (United States)

2016-08-01

The Wind Turbine Drivetrain Reliability Collaborative Workshop was convened by the National Renewable Energy Laboratory (NREL), Argonne National Laboratory, and the U.S. Department of Energy to explore the state of the art in wind turbine drivetrain mechanical system reliability as well as research and development (R&D) challenges that if solved could have significant benefits. The workshop was held at the Research Support Facility on NREL's main campus in Golden, Colorado, from February 16-17, 2016. More than 120 attendees participated from industry, academia, and government. Plenary presentations covered wind turbine drivetrain design, testing, and analysis; tribology -- the science and engineering of interacting surfaces in relative motion -- and failure modes; and condition monitoring and data analytics. In addition to the presentations, workshops were held in each of these areas to discuss R&D challenges. This report serves as a summary of the presentations, workshops, and conclusions on R&D challenges in wind turbine drivetrain reliability.

Research on Dynamic Coupled Characteristics of A Tracked Vehicle Gearbox

Directory of Open Access Journals (Sweden)

Hui Liu

2011-12-01

Full Text Available A tracked vehicle gearbox is divided into two subsystems-housing and gear train. Dynamic behaviors of the two subsystems are coupled practically. And the coupled characteristics describe the integrative dynamic behaviors of gearbox. This study proposes a coupled simulation model to investigate the interrelationship between dynamics of two subsystems. Multi-source excitations are numerically calculated to provide boundary conditions. The flexibility of transmission shafts and housing is mathematically described based on mode superposition. The coupled dynamic characteristics are analyzed with dynamics simulation computation. The flexibility of housing is one of the main causes to induce the fluctuation of dynamic responses of transmission shafts. The experimental results show that the proposed method is accurate through comparison of simulation results and test data.

Electrical gearbox equivalent by means of dynamic machine operation

NARCIS (Netherlands)

Gerrits, T.; Wijnands, C.G.E.; Paulides, J.J.H.; Duarte, J.L.

2011-01-01

A dynamic propulsion system using variable torque/speed characteristics, designed to realize a machine integrated equivalent of a gearbox is presented. This is achieved through adaption of the machine characteristics, and driven by specialized power electronics, leading to a reconfigurable stator

On the mechanical friction losses occurring in automotive differential gearboxes.

Science.gov (United States)

Antoni, Grégory

2014-01-01

In the automobile industry, the mechanical losses resulting from friction are largely responsible for various kinds of surface damage, such as the scuffing occurring in some mechanical assemblies. These scuffing processes seem to be due to a local loss of lubrication between certain mechanical elements of the same assembly, leading to a sharp increase in the friction, which can lead to a surface and volume damage in some of them, and even can cause, in the worst case, the whole destruction of the mechanical system if it has continued to operate. Predicting and checking the occurrence of this kind of undesirable phenomena, especially in some principal systems of the vehicle, represents nowadays, a crucial challenge in terms of automobile reliability and safety. This study focuses on the mechanical friction losses liable to occur in differential automobile gearboxes, which can lead in the long term to the scuffing of these mechanical systems. The friction losses involved were modeled, using a simple analytical approach, which is presented and discussed.

Multi-Stage Feature Selection by Using Genetic Algorithms for Fault Diagnosis in Gearboxes Based on Vibration Signal

Directory of Open Access Journals (Sweden)

Mariela Cerrada

2015-09-01

Full Text Available There are growing demands for condition-based monitoring of gearboxes, and techniques to improve the reliability, effectiveness and accuracy for fault diagnosis are considered valuable contributions. Feature selection is still an important aspect in machine learning-based diagnosis in order to reach good performance in the diagnosis system. The main aim of this research is to propose a multi-stage feature selection mechanism for selecting the best set of condition parameters on the time, frequency and time-frequency domains, which are extracted from vibration signals for fault diagnosis purposes in gearboxes. The selection is based on genetic algorithms, proposing in each stage a new subset of the best features regarding the classifier performance in a supervised environment. The selected features are augmented at each stage and used as input for a neural network classifier in the next step, while a new subset of feature candidates is treated by the selection process. As a result, the inherent exploration and exploitation of the genetic algorithms for finding the best solutions of the selection problem are locally focused. The Sensors 2015, 15 23904 approach is tested on a dataset from a real test bed with several fault classes under different running conditions of load and velocity. The model performance for diagnosis is over 98%.

Customized Multiwavelets for Planetary Gearbox Fault Detection Based on Vibration Sensor Signals

Directory of Open Access Journals (Sweden)

Lue Chen

2013-01-01

Full Text Available Planetary gearboxes exhibit complicated dynamic responses which are more difficult to detect in vibration signals than fixed-axis gear trains because of the special gear transmission structures. Diverse advanced methods have been developed for this challenging task to reduce or avoid unscheduled breakdown and catastrophic accidents. It is feasible to make fault features distinct by using multiwavelet denoising which depends on the feature separation and the threshold denoising. However, standard and fixed multiwavelets are not suitable for accurate fault feature detections because they are usually independent of the measured signals. To overcome this drawback, a method to construct customized multiwavelets based on the redundant symmetric lifting scheme is proposed in this paper. A novel indicator which combines kurtosis and entropy is applied to select the optimal multiwavelets, because kurtosis is sensitive to sharp impulses and entropy is effective for periodic impulses. The improved neighboring coefficients method is introduced into multiwavelet denoising. The vibration signals of a planetary gearbox from a satellite communication antenna on a measurement ship are captured under various motor speeds. The results show the proposed method could accurately detect the incipient pitting faults on two neighboring teeth in the planetary gearbox.

Vibration based condition monitoring of a multistage epicyclic gearbox in lifting cranes

Science.gov (United States)

Assaad, Bassel; Eltabach, Mario; Antoni, Jérôme

2014-01-01

This paper proposes a model-based technique for detecting wear in a multistage planetary gearbox used by lifting cranes. The proposed method establishes a vibration signal model which deals with cyclostationary and autoregressive models. First-order cyclostationarity is addressed by the analysis of the time synchronous average (TSA) of the angular resampled vibration signal. Then an autoregressive model (AR) is applied to the TSA part in order to extract a residual signal containing pertinent fault signatures. The paper also explores a number of methods commonly used in vibration monitoring of planetary gearboxes, in order to make comparisons. In the experimental part of this study, these techniques are applied to accelerated lifetime test bench data for the lifting winch. After processing raw signals recorded with an accelerometer mounted on the outside of the gearbox, a number of condition indicators (CIs) are derived from the TSA signal, the residual autoregressive signal and other signals derived using standard signal processing methods. The goal is to check the evolution of the CIs during the accelerated lifetime test (ALT). Clarity and fluctuation level of the historical trends are finally considered as a criteria for comparing between the extracted CIs.

Recommendations on Model Fidelity for Wind Turbine Gearbox Simulations; NREL (National Renewable Energy Laboratory)

Energy Technology Data Exchange (ETDEWEB)

Keller, J.; Lacava, W.; Austin, J.; Nejad, A.; Halse, C.; Bastard, L.; Helsen, J.

2015-02-01

This work investigates the minimum level of fidelity required to accurately simulate wind turbine gearboxes using state-of-the-art design tools. Excessive model fidelity including drivetrain complexity, gearbox complexity, excitation sources, and imperfections, significantly increases computational time, but may not provide a commensurate increase in the value of the results. Essential designparameters are evaluated, including the planetary load-sharing factor, gear tooth load distribution, and sun orbit motion. Based on the sensitivity study results, recommendations for the minimum model fidelities are provided.

Gearbox Fault Diagnosis in a Wind Turbine Using Single Sensor Based Blind Source Separation

Directory of Open Access Journals (Sweden)

Yuning Qian

2016-01-01

Full Text Available This paper presents a single sensor based blind source separation approach, namely, the wavelet-assisted stationary subspace analysis (WSSA, for gearbox fault diagnosis in a wind turbine. Continuous wavelet transform (CWT is used as a preprocessing tool to decompose a single sensor measurement data into a set of wavelet coefficients to meet the multidimensional requirement of the stationary subspace analysis (SSA. The SSA is a blind source separation technique that can separate the multidimensional signals into stationary and nonstationary source components without the need for independency and prior information of the source signals. After that, the separated nonstationary source component with the maximum kurtosis value is analyzed by the enveloping spectral analysis to identify potential fault-related characteristic frequencies. Case studies performed on a wind turbine gearbox test system verify the effectiveness of the WSSA approach and indicate that it outperforms independent component analysis (ICA and empirical mode decomposition (EMD, as well as the spectral-kurtosis-based enveloping, for wind turbine gearbox fault diagnosis.

Non-Dispersive Infrared Sensor for Online Condition Monitoring of Gearbox Oil

Directory of Open Access Journals (Sweden)

Markus S. Rauscher

2017-02-01

Full Text Available The condition of lubricating oil used in automotive and industrial gearboxes must be controlled in order to guarantee optimum performance and prevent damage to machinery parts. In normal practice, this is done by regular oil change intervals and routine laboratory analysis, both of which involve considerable operating costs. In this paper, we present a compact and robust optical sensor that can be installed in the lubrication circuit to provide quasi-continuous information about the condition of the oil. The measuring principle is based on non-dispersive infrared spectroscopy. The implemented sensor setup consists of an optical measurement cell, two thin-film infrared emitters, and two four-channel pyroelectric detectors equipped with optical bandpass filters. We present a method based on multivariate partial least squares regression to select appropriate optical bandpass filters for monitoring the oxidation, water content, and acid number of the oil. We perform a ray tracing analysis to analyze and correct the influence of the light path in the optical setup on the optical parameters of the bandpass filters. The measurement values acquired with the sensor for three different gearbox oil types show high correlation with laboratory reference data for the oxidation, water content, and acid number. The presented sensor can thus be a useful supplementary tool for the online condition monitoring of lubricants when integrated into a gearbox oil circuit.

Influence of Multiharmonics Excitation on Rattle Noise in Automotive Gearboxes

Directory of Open Access Journals (Sweden)

Y. Kadmiri

2011-01-01

Full Text Available We consider the automotive gearbox rattle noise resulting from vibro-impacts that can occur between the idle gears under excessive velocity fluctuations of the shaft-driving gears imposed by engine torque fluctuation. Even if the rattling phenomenon has no consequence on reliability, it may be particularly annoying for vehicle interior sound quality and acoustic comfort. The main parameters governing such kind of vibrations are the excitation source associated with engine torque fluctuation which can be modeled by an imposed displacement of the driveline, the inertia of the idle gear, the drag torque acting during the free flight motion, and the impact laws. In the case of rattle, it is reasonable to assume that duration of impacts between teeth is very short compared to the excitation period. Then, these impacts are modeled by a coefficient of restitution law. The excitation source is not composed only with fundamental component but also with other harmonic components. This study presents some effects of these additional components on the dynamic response of the idle gear.

Condition Indicators for Gearbox Condition Monitoring Systems

Directory of Open Access Journals (Sweden)

P. Večeř

2005-01-01

Full Text Available Condition monitoring systems for manual transmissions based on vibration diagnostics are widely applied in industry. The systems deal with various condition indicators, most of which are focused on a specific type of gearbox fault. Frequently used condition indicators (CIs are described in this paper. The ability of a selected condition indicator to describe the degree of gearing wear was tested using vibration signals acquired during durability testing of manual transmission with helical gears. 

An Approach for the Dynamic Measurement of Ring Gear Strains of Planetary Gearboxes Using Fiber Bragg Gratings

Directory of Open Access Journals (Sweden)

Hang Niu

2017-12-01

Full Text Available The strain of the ring gear can reflect the dynamic characteristics of planetary gearboxes directly, which makes it an ideal signal to monitor the health condition of the gearbox. To overcome the disadvantages of traditional methods, a new approach for the dynamic measurement of ring gear strains using fiber Bragg gratings (FBGs is proposed in this paper. Firstly, the installation of FBGs is determined according to the analysis for the strain distribution of the ring gear. Secondly, the parameters of the FBG are determined in consideration of the accuracy and sensitivity of the measurement as well as the size of the ring gear. The strain measured by the FBG is then simulated under non-uniform strain field conditions. Thirdly, a dynamic measurement system is built and tested. Finally, the strains of the ring gear are measured in a planetary gearbox under normal and faulty conditions. The experimental results showed good agreement with the theoretical results in values, trends, and the fault features can be seen from the time domain of the measured strain signal, which proves that the proposed method is feasible for the measurement of the ring gear strains of planetary gearboxes.

An Approach for the Dynamic Measurement of Ring Gear Strains of Planetary Gearboxes Using Fiber Bragg Gratings.

Science.gov (United States)

Niu, Hang; Zhang, Xiaodong; Hou, Chenggang

2017-12-16

The strain of the ring gear can reflect the dynamic characteristics of planetary gearboxes directly, which makes it an ideal signal to monitor the health condition of the gearbox. To overcome the disadvantages of traditional methods, a new approach for the dynamic measurement of ring gear strains using fiber Bragg gratings (FBGs) is proposed in this paper. Firstly, the installation of FBGs is determined according to the analysis for the strain distribution of the ring gear. Secondly, the parameters of the FBG are determined in consideration of the accuracy and sensitivity of the measurement as well as the size of the ring gear. The strain measured by the FBG is then simulated under non-uniform strain field conditions. Thirdly, a dynamic measurement system is built and tested. Finally, the strains of the ring gear are measured in a planetary gearbox under normal and faulty conditions. The experimental results showed good agreement with the theoretical results in values, trends, and the fault features can be seen from the time domain of the measured strain signal, which proves that the proposed method is feasible for the measurement of the ring gear strains of planetary gearboxes.

Very High Frequency Monitoring System for Engine Gearbox and Generator Health Management (Postprint)

National Research Council Canada - National Science Library

Watson, Matthew J; Byington, Carl S; Behbahani, Alireza

2007-01-01

...) vibration monitoring system that integrates various vibro-acoustic data with intelligent feature extraction and fault isolation algorithms to effectively assess engine gearbox and generator health...

Application of Artificial Neural Network for Damage Detection in Planetary Gearbox of Wind Turbine

Directory of Open Access Journals (Sweden)

Marcin Strączkiewicz

2016-01-01

Full Text Available In the monitoring process of wind turbines the utmost attention should be given to gearboxes. This conclusion is derived from numerous summary papers. They reveal that, on the one hand, gearboxes are one of the most fault susceptible elements in the drive-train and, on the other, the most expensive to replace. Although state-of-the-art CMS can usually provide advanced signal processing tools for extraction of diagnostic information, there are still many installations, where the diagnosis is based simply on the averaged wideband features like root-mean-square (RMS or peak-peak (PP. Furthermore, for machinery working in highly changing operational conditions, like wind turbines, those estimators are strongly fluctuating, and this fluctuation is not linearly correlated to operation parameters. Thus, the sudden increase of a particular feature does not necessarily have to indicate the development of fault. To overcome this obstacle, it is proposed to detect a fault development with Artificial Neural Network (ANN and further observation of linear regression parameters calculated on the estimation error between healthy and unknown condition. The proposed reasoning is presented on the real life example of ring gear fault in wind turbine’s planetary gearbox.

Advanced Propfan Engine Technology (APET) definition study, single and counter-rotation gearbox/pitch change mechanism design

Science.gov (United States)

Anderson, R. D.

1985-01-01

Single-rotation propfan-powered regional transport aircraft were studied to identify key technology development issues and programs. The need for improved thrust specific fuel consumption to reduce fuel burned and aircraft direct operating cost is the dominant factor. Typical cycle trends for minimizing fuel consumption are reviewed, and two 10,000 shp class engine configurations for propfan propulsion systems for the 1990's are presented. Recommended engine configurations are both three-spool design with dual spool compressors and free power turbines. The benefits of these new propulsion system concepts were evaluated using an advanced airframe, and results are compared for single-rotation propfan and turbofan advanced technology propulsion systems. The single-rotation gearbox is compared to a similar design with current technology to establish the benefits of the advanced gearbox technology. The conceptual design of the advanced pitch change mechanism identified a high pressure hydraulic system that is superior to the other contenders and completely external to the gearboxes.

A fault diagnosis scheme for planetary gearboxes using adaptive multi-scale morphology filter and modified hierarchical permutation entropy

Science.gov (United States)

Li, Yongbo; Li, Guoyan; Yang, Yuantao; Liang, Xihui; Xu, Minqiang

2018-05-01

The fault diagnosis of planetary gearboxes is crucial to reduce the maintenance costs and economic losses. This paper proposes a novel fault diagnosis method based on adaptive multi-scale morphological filter (AMMF) and modified hierarchical permutation entropy (MHPE) to identify the different health conditions of planetary gearboxes. In this method, AMMF is firstly adopted to remove the fault-unrelated components and enhance the fault characteristics. Second, MHPE is utilized to extract the fault features from the denoised vibration signals. Third, Laplacian score (LS) approach is employed to refine the fault features. In the end, the obtained features are fed into the binary tree support vector machine (BT-SVM) to accomplish the fault pattern identification. The proposed method is numerically and experimentally demonstrated to be able to recognize the different fault categories of planetary gearboxes.

ALGORITHM OF WORK OF SYSTEM OF MANAGEMENT BY AUTOMATED GEAR-BOXES CARS

Directory of Open Access Journals (Sweden)

O. Smirnov

2009-01-01

Full Text Available The development of algorithms of management system’s work by the automated gear-boxes vehicles is considered and the results of their practical use on the example of the KamAZ truck are considered.

Multilevel Analysis of Continuous AE from Helicopter Gearbox

Czech Academy of Sciences Publication Activity Database

Chlada, Milan; Převorovský, Zdeněk; Heřmánek, Jan; Krofta, Josef

2014-01-01

Roč. 19, č. 12 (2014) ISSN 1435-4934. [European Conference on Non-Destructive Testing (ECNDT 2014) /11./. Praha, 06.10.2014-10.10.2014] R&D Projects: GA MPO FR-TI3/755 Institutional support: RVO:61388998 Keywords : structural health monitoring (SHM) * signal processing * acoustic emission (AE) * diagnostics of helicopter gearbox * wavelet analysis * continuous acoustic emission Subject RIV: JU - Aeronautics, Aerodynamics, Aircrafts http://www.ndt.net/events/ECNDT2014/app/content/Paper/630_Chlada_Rev1.pdf

Frequency analysis of a two-stage planetary gearbox using two different methodologies

Science.gov (United States)

Feki, Nabih; Karray, Maha; Khabou, Mohamed Tawfik; Chaari, Fakher; Haddar, Mohamed

2017-12-01

This paper is focused on the characterization of the frequency content of vibration signals issued from a two-stage planetary gearbox. To achieve this goal, two different methodologies are adopted: the lumped-parameter modeling approach and the phenomenological modeling approach. The two methodologies aim to describe the complex vibrations generated by a two-stage planetary gearbox. The phenomenological model describes directly the vibrations as measured by a sensor fixed outside the fixed ring gear with respect to an inertial reference frame, while results from a lumped-parameter model are referenced with respect to a rotating frame and then transferred into an inertial reference frame. Two different case studies of the two-stage planetary gear are adopted to describe the vibration and the corresponding spectra using both models. Each case presents a specific geometry and a specific spectral structure.

'GRC1.5': Uptower Gearbox Testing to Investigate Bearing Axial Cracking

Energy Technology Data Exchange (ETDEWEB)

Keller, Jonathan; Vaes, David; McNiff, Brian

2016-02-16

This presentation focuses on the investigation of bearing axial cracking using the GRC1.5 uptower gearbox. Topics covered include the testing options considered, the project goal, and current and near-term activities.

Summary of the Large Civil Tiltrotor (LCTR2) Engine Gearbox Study

Science.gov (United States)

Snyder, Christopher A.; Robuck, Mark; Wilkerson, Joseph; Nordstrom, Carl

2010-01-01

In support of the Fundamental Aeronautics Program, Subsonic Rotary Wing Project, NASA is continuing to study the Large Civil Tiltrotor (LCTR) concept to help define/refine vehicle, system and subsystem attributes. These attributes can then be used to define performance requirements and identify new or advanced technologies to achieve an operational vehicle class. As part of this goal, NASA contracted with The Boeing Company and its subcontractor Rolls-Royce to perform an investigation of different combinations of engine and gearbox variability to achieve a maximum of 50 percent rotor tip speed reduction from hover to cruise conditions. Previous NASA studies identified the 50 percent rotor speed reduction minimized vehicle gross weight and fuel burn. The LCTR2 (LCTR-iteration 2) was the contracted study baseline for initial sizing. Rotor tip speed ratios (cruise to hover) of 100, 77, and 54 percent were analyzed for each combination of engine and gearbox speed reduction to achieve the chosen rotor tip speed ratio. Three different engine and gearbox technology levels were assumed; commercial off-the-shelf (COTS), entry-in-service (EIS) in 2025 and EIS in 2035. These technology levels were applied to determine each particular effect on vehicle gross weight and fuel burn, while other vehicle technologies were assumed constant. This report summarizes the work performed that is being put together into a comprehensive NASA contractor report. Some background on the LCTR concept and baseline vehicle will be given and then a discussion concerning the technical approach utilized. Major study assumptions and results will be presented and discussed. Finally conclusions will be drawn as well as suggestions provided for future efforts.

Analyzing the Wheeled Vehicle Gearbox Structures for Running in Harsh Conditions

Directory of Open Access Journals (Sweden)

V. V. Vasiliev

2015-01-01

Full Text Available In domestic automotive industry the need for transition from transmission with manual control to automatic gearboxes (GB emerged long ago. Regarding the leading foreign manufacturers (Allison, ZF, Eaton, etc., an experience in design of automatic transmissions and the level of technological development is incomparably small. Thus, to have an informed choice of the gearbox structure types and control system is a relevant problem. Application efficiency of this or other gearbox depends both on its adaptability to the actual operating conditions and on the quality of transition refinement. This paper analyzes the special features of the gear change process in the most common types of automatic gearboxes. Constructive feasibilities of an "ideal" gear change (without power loss and strategies for gear shifting are compared. The paper offers an overview of common problems when achieving these goals and the ways to solve them. An automatic transmission of the particular type used in the wheeled vehicles under off-road conditions determines the probability of maintaining their mobility. This is due to the phenomenon of wheel`s breakdown to slipping caused by sharp increase of torque on the wheel. Planetary hydromechanical transmissions (AT provide continuous input torque to the wheels, but they are expensive and difficult to manufacture and use. Besides, to provide a high number of density ratios in them is more complicated than in the automated and manual transmissions (AMT. This is important when moving long in the lower gears under difficult conditions. Compared with AT dual clutch transmissions due to design features require even more precise and fast control system of actuators and engine. Automation of constant-mesh or synchromesh transmissions provides a significant reduction in the duration of interruption in torque delivery. If it is not enough to increase mobility in the harsh conditions, a rational choice is to use a transmission type of TCCT

Joint High-Order Synchrosqueezing Transform and Multi-Taper Empirical Wavelet Transform for Fault Diagnosis of Wind Turbine Planetary Gearbox under Nonstationary Conditions

Directory of Open Access Journals (Sweden)

Yue Hu

2018-01-01

Full Text Available Wind turbines usually operate under nonstationary conditions, such as wide-range speed fluctuation and time-varying load. Its critical component, the planetary gearbox, is prone to malfunction or failure, which leads to downtime and repair costs. Therefore, fault diagnosis and condition monitoring for the planetary gearbox in wind turbines is a vital research topic. Meanwhile, the signals measured by the vibration sensors mounted in the gearbox exhibit time-varying and nonstationary features. In this study, a novel time-frequency method based on high-order synchrosqueezing transform (SST and multi-taper empirical wavelet transform (MTEWT is proposed for the wind turbine planetary gearbox under nonstationary conditions. The high-order SST uses accurate instantaneous frequency approximations to obtain a sharper time-frequency representation (TFR. As the acquired signal consists of many components, like the meshing and rotating components of the gear and bearing, the fault component may be masked by other unrelated components. The MTEWT is used to separate the fault feature from the masking components. A variety of experimental signals of the wind turbine planetary gearbox under nonstationary conditions have been analyzed to demonstrate the effectiveness and robustness of the proposed method. Results show that the proposed method is effective in diagnosing both gear and bearing faults.

Joint High-Order Synchrosqueezing Transform and Multi-Taper Empirical Wavelet Transform for Fault Diagnosis of Wind Turbine Planetary Gearbox under Nonstationary Conditions.

Science.gov (United States)

Hu, Yue; Tu, Xiaotong; Li, Fucai; Meng, Guang

2018-01-07

Wind turbines usually operate under nonstationary conditions, such as wide-range speed fluctuation and time-varying load. Its critical component, the planetary gearbox, is prone to malfunction or failure, which leads to downtime and repair costs. Therefore, fault diagnosis and condition monitoring for the planetary gearbox in wind turbines is a vital research topic. Meanwhile, the signals measured by the vibration sensors mounted in the gearbox exhibit time-varying and nonstationary features. In this study, a novel time-frequency method based on high-order synchrosqueezing transform (SST) and multi-taper empirical wavelet transform (MTEWT) is proposed for the wind turbine planetary gearbox under nonstationary conditions. The high-order SST uses accurate instantaneous frequency approximations to obtain a sharper time-frequency representation (TFR). As the acquired signal consists of many components, like the meshing and rotating components of the gear and bearing, the fault component may be masked by other unrelated components. The MTEWT is used to separate the fault feature from the masking components. A variety of experimental signals of the wind turbine planetary gearbox under nonstationary conditions have been analyzed to demonstrate the effectiveness and robustness of the proposed method. Results show that the proposed method is effective in diagnosing both gear and bearing faults.

Comparison and Implementation of a Rigid and a Flexible Multibody Planetary Gearbox Model

DEFF Research Database (Denmark)

Jørgensen, Martin Felix; Pedersen, Niels Leergaard; Sørensen, Jens Nørkær

2014-01-01

We propose algorithms for developing (1) a rigid (constrained) and (2) a flexible planetary gearbox model. The two methods are compared against each other and advantages/disadvantages of each method are discussed. The rigid model (1) has gear tooth reaction forces expressed by Lagrange multipliers...... between one and two gear teeth in mesh. The final results are from modelling the planetary gearbox in a 500 kW wind turbine which we also described in Jørgensen et al. (2013)........ The flexible approach (2) is being compared with the gear tooth forces from the rigid approach, first without damping and second the influence of damping is examined. Variable stiffness as a function of base circle arc length is implemented in the flexible approach such that it handles the realistic switch...

Planetary gearbox fault feature enhancement based on combined adaptive filter method

Directory of Open Access Journals (Sweden)

Shuangshu Tian

2015-12-01

Full Text Available The reliability of vibration signals acquired from a planetary gear system (the indispensable part of wind turbine gearbox is directly related to the accuracy of fault diagnosis. The complex operation environment leads to lots of interference signals which are included in the vibration signals. Furthermore, both multiple gears meshing with each other and the differences in transmission rout produce strong nonlinearity in the vibration signals, which makes it difficult to eliminate the noise. This article presents a combined adaptive filter method by taking a delayed signal as reference signal, the Self-Adaptive Noise Cancellation method is adopted to eliminate the white noise. In the meanwhile, by applying Gaussian function to transform the input signal into high-dimension feature-space signal, the kernel least mean square algorithm is used to cancel the nonlinear interference. Effectiveness of the method has been verified by simulation signals and test rig signals. By dealing with simulation signal, the signal-to-noise ratio can be improved around 30 dB (white noise and the amplitude of nonlinear interference signal can be depressed up to 50%. Experimental results show remarkable improvements and enhance gear fault features.

Effects of pressure angle and tip relief on the life of speed increasing gearbox: a case study.

Science.gov (United States)

Shanmugasundaram, Sankar; Kumaresan, Manivarma; Muthusamy, Nataraj

2014-01-01

This paper examines failure of helical gear in speed increasing gearbox used in the wind turbine generator (WTG). In addition, an attempt has been made to get suitable gear micro-geometry such as pressure angle and tip relief to minimize the gear failure in the wind turbines. As the gear trains in the wind turbine gearbox is prearranged with higher speed ratio and the gearboxes experience shock load due to atmospheric turbulence, gust wind speed, non-synchronization of pitching, frequent grid drops and failure of braking, the gear failure occurs either in the intermediate or high speed stage pinion. KISS soft gear calculation software was used to determine the gear specifications and analysis is carried out in ANSYS software version.11.0 for the existing and the proposed gear to evaluate the performance of bending stress tooth deflection and stiffness. The main objective of this research study is to propose suitable gear micro-geometry that is tip relief and pressure angle blend for increasing tooth strength of the helical gear used in the wind turbine for trouble free operation.

A diagnostic signal selection scheme for planetary gearbox vibration monitoring under non-stationary operational conditions

International Nuclear Information System (INIS)

Feng, Ke; Wang, KeSheng; Zhang, Mian; Ni, Qing; Zuo, Ming J

2017-01-01

The planetary gearbox, due to its unique mechanical structures, is an important rotating machine for transmission systems. Its engineering applications are often in non-stationary operational conditions, such as helicopters, wind energy systems, etc. The unique physical structures and working conditions make the vibrations measured from planetary gearboxes exhibit a complex time-varying modulation and therefore yield complicated spectral structures. As a result, traditional signal processing methods, such as Fourier analysis, and the selection of characteristic fault frequencies for diagnosis face serious challenges. To overcome this drawback, this paper proposes a signal selection scheme for fault-emphasized diagnostics based upon two order tracking techniques. The basic procedures for the proposed scheme are as follows. (1) Computed order tracking is applied to reveal the order contents and identify the order(s) of interest. (2) Vold–Kalman filter order tracking is used to extract the order(s) of interest—these filtered order(s) constitute the so-called selected vibrations. (3) Time domain statistic indicators are applied to the selected vibrations for faulty information-emphasized diagnostics. The proposed scheme is explained and demonstrated in a signal simulation model and experimental studies and the method proves to be effective for planetary gearbox fault diagnosis. (paper)

Numerical analysis and experimental investigation of modalproperties for the gearbox in wind turbine

Institute of Scientific and Technical Information of China (English)

Pengxing; YI; Peng; HUANG; Tielin; SHI

2016-01-01

Wind turbine gearbox （WTG）, which functionsas an accelerator, ensures theof wind turbine systems.performance and service lifeThis paper examines thedistinctive modal properties of WTGs through finiteelement （FE） and experimental modal analyses. Thestudy is performed in two parts. First, a whole systemmodel is developed to investigate the first 10 modalfrequencies and mode shapes of WTG using flexible multi-body modeling techniques. Given the complex structureand operating conditions of WTG, this study applies springelements to the model and quantifies how the beatings andgear pair interactions affect the dynamic characteristics ofWTGs. Second, the FE modal results are validated throughexperimental modal analyses of a 1.5 WM WTG using thefrequency response function method of single pointexcitation and multi-point response. The natural frequen-cies from the FE and experimental modal analyses showfavorable agreement and reveal that the characteristicfrequency of the studied gearbox avoids its eigen-frequency very well.

Application of lifting wavelet and random forest in compound fault diagnosis of gearbox

Science.gov (United States)

Chen, Tang; Cui, Yulian; Feng, Fuzhou; Wu, Chunzhi

2018-03-01

Aiming at the weakness of compound fault characteristic signals of a gearbox of an armored vehicle and difficult to identify fault types, a fault diagnosis method based on lifting wavelet and random forest is proposed. First of all, this method uses the lifting wavelet transform to decompose the original vibration signal in multi-layers, reconstructs the multi-layer low-frequency and high-frequency components obtained by the decomposition to get multiple component signals. Then the time-domain feature parameters are obtained for each component signal to form multiple feature vectors, which is input into the random forest pattern recognition classifier to determine the compound fault type. Finally, a variety of compound fault data of the gearbox fault analog test platform are verified, the results show that the recognition accuracy of the fault diagnosis method combined with the lifting wavelet and the random forest is up to 99.99%.

A new oil debris sensor for online condition monitoring of wind turbine gearboxes

DEFF Research Database (Denmark)

Wang, Chao; Liu, Hui; Liu, Xiao

2015-01-01

Online Condition Monitoring (CM) is a key technology for the Operation and Maintenance (O&M) of wind turbines. Lubricating oil is the blood of the wind turbine gearbox. Metal debris in lubricating oil contains abundant information regarding the ageing and wear/damage of mechanical transmission sy...

Study on development system of increasing gearbox for high-performance wind-power generator

Science.gov (United States)

Xu, Hongbin; Yan, Kejun; Zhao, Junyu

2005-12-01

Based on the analysis of the development potentiality of wind-power generator and domestic manufacture of its key parts in China, an independent development system of the Increasing Gearbox for High-performance Wind-power Generator (IGHPWG) was introduced. The main elements of the system were studied, including the procedure design, design analysis system, manufacturing technology and detecting system, and the relative important technologies were analyzed such as mixed optimal joint transmission structure of the first planetary drive with two grade parallel axle drive based on equal strength, tooth root round cutting technology before milling hard tooth surface, high-precise tooth grinding technology, heat treatment optimal technology and complex surface technique, and rig test and detection technique of IGHPWG. The development conception was advanced the data share and quality assurance system through all the elements of the development system. The increasing Gearboxes for 600KW and 1MW Wind-power Generator have been successfully developed through the application of the development system.

Multidisciplinary Inverse Reliability Analysis Based on Collaborative Optimization with Combination of Linear Approximations

Directory of Open Access Journals (Sweden)

Xin-Jia Meng

2015-01-01

Full Text Available Multidisciplinary reliability is an important part of the reliability-based multidisciplinary design optimization (RBMDO. However, it usually has a considerable amount of calculation. The purpose of this paper is to improve the computational efficiency of multidisciplinary inverse reliability analysis. A multidisciplinary inverse reliability analysis method based on collaborative optimization with combination of linear approximations (CLA-CO is proposed in this paper. In the proposed method, the multidisciplinary reliability assessment problem is first transformed into a problem of most probable failure point (MPP search of inverse reliability, and then the process of searching for MPP of multidisciplinary inverse reliability is performed based on the framework of CLA-CO. This method improves the MPP searching process through two elements. One is treating the discipline analyses as the equality constraints in the subsystem optimization, and the other is using linear approximations corresponding to subsystem responses as the replacement of the consistency equality constraint in system optimization. With these two elements, the proposed method realizes the parallel analysis of each discipline, and it also has a higher computational efficiency. Additionally, there are no difficulties in applying the proposed method to problems with nonnormal distribution variables. One mathematical test problem and an electronic packaging problem are used to demonstrate the effectiveness of the proposed method.

RICE: A Reliable and Efficient Remote Instrumentation Collaboration Environment

Directory of Open Access Journals (Sweden)

Prasad Calyam

2008-01-01

Full Text Available Remote access of scientific instruments over the Internet (i.e., remote instrumentation demand high-resolution (2D and 3D video image transfers with simultaneous real-time mouse and keyboard controls. Consequently, user quality of experience (QoE is highly sensitive to network bottlenecks. Further, improper user control while reacting to impaired video caused due to network bottlenecks could result in physical damages to the expensive instrument equipment. Hence, it is vital to understand the interplay between (a user keyboard/mouse actions toward the instrument, and (b corresponding network reactions for transfer of instrument video images toward the user. In this paper, we first present an analytical model for characterizing user and network interplay during remote instrumentation sessions in terms of demand and supply interplay principles of traditional economics. Next, we describe the trends of the model parameters using subjective and objective measurements obtained from QoE experiments. Thereafter, we describe our Remote Instrumentation Collaboration Environment (RICE software that leverages our experiences from the user and network interplay studies, and has functionalities that facilitate reliable and efficient remote instrumentation such as (a network health awareness to detect network bottleneck periods, and (b collaboration tools for multiple participants to interact during research and training sessions.

Wind Turbine Drivetrain Condition Monitoring During GRC Phase 1 and Phase 2 Testing

Energy Technology Data Exchange (ETDEWEB)

Sheng, S.; Link, H.; LaCava, W.; van Dam, J.; McNiff, B.; Veers, P.; Keller, J.; Butterfield, S.; Oyague, F.

2011-10-01

This report will present the wind turbine drivetrain condition monitoring (CM) research conducted under the phase 1 and phase 2 Gearbox Reliability Collaborative (GRC) tests. The rationale and approach for this drivetrain CM research, investigated CM systems, test configuration and results, and a discussion on challenges in wind turbine drivetrain CM and future research and development areas, will be presented.

An Investigation of Vibration Signal Averaging of Individual Components in an Epicyclic Gearbox

Science.gov (United States)

1991-06-01

kHz. These were mounted on a set of small steel blocks bonded to the gearbox casing at various positions. A six channel PCB charge amplifying power... callable library of routines, ATLAB, available with the data acquisition card was used to acquire the digitised data into Fortran 2-byte integer arrays. A

A novelty detection diagnostic methodology for gearboxes operating under fluctuating operating conditions using probabilistic techniques

Science.gov (United States)

Schmidt, S.; Heyns, P. S.; de Villiers, J. P.

2018-02-01

In this paper, a fault diagnostic methodology is developed which is able to detect, locate and trend gear faults under fluctuating operating conditions when only vibration data from a single transducer, measured on a healthy gearbox are available. A two-phase feature extraction and modelling process is proposed to infer the operating condition and based on the operating condition, to detect changes in the machine condition. Information from optimised machine and operating condition hidden Markov models are statistically combined to generate a discrepancy signal which is post-processed to infer the condition of the gearbox. The discrepancy signal is processed and combined with statistical methods for automatic fault detection and localisation and to perform fault trending over time. The proposed methodology is validated on experimental data and a tacholess order tracking methodology is used to enhance the cost-effectiveness of the diagnostic methodology.

Dynamic Modeling of Wind Turbine Gearboxes and Experimental Validation

DEFF Research Database (Denmark)

Pedersen, Rune

Grinding corrections are often applied to gear teeth, which will alter the load distribution across the tooth. Grinding corrections will also change the load sharing between neighboring tooth pairs, and in turn the gear mesh stiffness. In this thesis, a model for calculating the gear mesh stiffness...... is presented. The model takes into account the effects of load and applied grinding corrections. The results are verified by comparing to simulated and experimental results reported in the existing literature. Using gear data loosely based on a 1 MW wind turbine gearbox, the gear mesh stiffness is expanded...

Residual signal feature extraction for gearbox planetary stage fault detection

DEFF Research Database (Denmark)

Skrimpas, Georgios Alexandros; Ursin, Thomas; Sweeney, Christian Walsted

2017-01-01

Faults in planetary gears and related bearings, e.g. planet bearings and planet carrier bearings, pose inherent difficulties on their accurate and consistent detection associated mainly to the low energy in slow rotating stages and the operating complexity of planetary gearboxes. In this work......, identification of the expected spectral signature for proper residual signal calculation and filtering of any frequency component not related to the planetary stage. Two field cases of planet carrier bearing defect and planet wheel spalling are presented and discussed, showing the efficiency of the followed...

Torsional analysis of 1 MW gearbox and shaft system in the Avedoere wind turbine

International Nuclear Information System (INIS)

Crone, A.

1993-05-01

In order to predict undesired high gear noise emission from the Avedoere wind turbine due to critical torsional resonances in the shaft system, the torsional natural frequencies and corresponding mode shapes have been calculated. The analysis has involved a comprehensive, detailed model of the gearbox shaft system. The natural frequencies and mode shapes have also been calculated for the test bed shaft system enabling a calibration of the calculations when comparing with measurements made on the test bed system. The natural torsional frequencies of the test bed shaft system and the wind turbine shaft system, both including the Flender, Peak 4375 gearbox, have been calculated together with the corresponding mode shapes. The sensitivity analysis showed that the natural frequencies of one of the torsional modes may be close to or coinciding with the toothmesh frequency of the output gear stage, in the wind turbine shaft system. The shape of this mode indicates however, that this mode is not very likely to be strongly excited by forces acting in the tooth contact at the mesh frequency. This conclusion also counts for a second mode which was calculated to have a natural frequency close to the toothmesh frequency of the output stage. The analysis also shows that the frequencies of the 1st, the 3rd and the 4th harmonics of the toothmesh frequency of the 2nd gear stage, deviate by less than 15% from several modes of the wind turbine shaft system, which seem likely to be excited by forces acting in the tooth contact of this stage. Amplification of the structure-borne noise from the gearbox at these frequencies may be expected. The amplification at these frequencies is not expected to have any critical influence on the tonal gear noise radiated from the wind turbine. (EG)

A Systematic Methodology for Gearbox Health Assessment and Fault Classification

Directory of Open Access Journals (Sweden)

Jay Lee

2011-01-01

Full Text Available A systematic methodology for gearbox health assessment and fault classification is developed and evaluated for 560 data sets of gearbox vibration data provided by the Prognostics and Health Management Society for the 2009 data challenge competition. A comprehensive set of signal processing and feature extraction methods are used to extract over 200 features, including features extracted from the raw time signal, time synchronous signal, wavelet decomposition signal, frequency domain spectrum, envelope spectrum, among others. A regime segmentation approach using the tachometer signal, a spectrum similarity metric, and gear mesh frequency peak information are used to segment the data by gear type, input shaft speed, and braking torque load. A health assessment method that finds the minimum feature vector sum in each regime is used to classify and find the 80 baseline healthy data sets. A fault diagnosis method based on a distance calculation from normal along with specific features correlated to different fault signatures is used to diagnosis specific faults. The fault diagnosis method is evaluated for the diagnosis of a gear tooth breakage, input shaft imbalance, bent shaft, bearing inner race defect, and bad key, and the method could be further extended for other faults as long as a set of features can be correlated with a known fault signature. Future work looks to further refine the distance calculation algorithm for fault diagnosis, as well as further evaluate other signal processing method such as the empirical mode decomposition to see if an improved set of features can be used to improve the fault diagnosis accuracy.

Using a Hybrid Cost-FMEA Analysis for Wind Turbine Reliability Analysis

Directory of Open Access Journals (Sweden)

Nacef Tazi

2017-02-01

Full Text Available Failure mode and effects analysis (FMEA has been proven to be an effective methodology to improve system design reliability. However, the standard approach reveals some weaknesses when applied to wind turbine systems. The conventional criticality assessment method has been criticized as having many limitations such as the weighting of severity and detection factors. In this paper, we aim to overcome these drawbacks and develop a hybrid cost-FMEA by integrating cost factors to assess the criticality, these costs vary from replacement costs to expected failure costs. Then, a quantitative comparative study is carried out to point out average failure rate, main cause of failure, expected failure costs and failure detection techniques. A special reliability analysis of gearbox and rotor-blades are presented.

Vibration analysis of 1 MW gearbox for the Avedoere wind turbine. Test bed measurements

International Nuclear Information System (INIS)

Crone, A.

1995-03-01

The investigations had several purposes: Firstly, to determine and evaluate the structure-borne noise source strength of the gearbox, which is relevant for the final gear noise emission from the wind turbine. Secondly, to select the potentially least noisy gear set out of two, which have been made for the output gear stage. And Thirdly, to obtain the natural vibration modes of the gearbox structure, in order to determine if the structure-borne noise, transmitted to the wind turbine structure, will be amplified due to resonance conditions. Additional vibration tests were carried out. Among these, trials of 'in situ' measurement of the Transmission Error of the output gear stage, and measurements of the torsional vibrations of the input and output shaft. The test of the two output gear sets (from Flender AG and ELKRAFT A.m.b.A.) had the aim to determine the least noisy one of two different tooth profiles. Both gear sets were intended for the Avedoere Wind Turbine when it, in its first period of operation, is going to operate as a stall regulated turbine. After the first mesurements and the exchange of the Flender-designed gear set with the ELKRAFT-designed gear set, troubles with the backmost bearing of the intermediate shaft arose. The evaluation of the structure-borne noise source strength (expressed as the vibration velocity level), has in general been made at load conditions which correspond to the conditions in the wind turibne at a wind speed of 8 m/s, 10 m above terrain (v 10 ). This condition, is the one normally used when the noise emission from wind turbines is evaluated. At the comparison of the two gear sets against each other, the influence of the torque load on the source strength has also been considered. This comparison may indicate the load at which the profile correction is most effective, and may determine the noise potential of the gearbox at wind speeds lower than 8 m/s, which could also be of interest

75 FR 27548 - Quality GearBox, LLC; Notice of Competing Preliminary Permit Application Accepted for Filing and...

Science.gov (United States)

2010-05-17

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 13718-000] Quality GearBox... project would consist of: (1) An existing 8.5-foot- high by 325-foot-long gravity dam; (2) an existing 19-acre impoundment with a storage capacity of 133 acre feet; (3) an existing filtration plant to be...

Characterization of cutting parameters in the minimum quantity lubricant (MQL) machining process of a gearbox

OpenAIRE

Travieso Rodriguez, Jose Antonio; Gómez Gras, David; García Vilana, Silvia; Mainau Noguer, Ferran; Jerez Mesa, Ramón

2015-01-01

This paper aims to find the key process parameters for machining different parts of an automobile gearbox, commissioned by a company that needs to replace with the MQL lubrication system their current machining process based on cutting fluids. It particularly focuses on the definition of appropriate cutting parameters for machining under the MQL condition through a statistical method of Design of Experiments (DOE). Using a combination of recommended parameters, significant improvements in the...

Cloud Incubator Car: A Reliable Platform for Autonomous Driving

Directory of Open Access Journals (Sweden)

Raúl Borraz

2018-02-01

Full Text Available It appears clear that the future of road transport is going through enormous changes (intelligent transport systems, the main one being the Intelligent Vehicle (IV. Automated driving requires a huge research effort in multiple technological areas: sensing, control, and driving algorithms. We present a comprehensible and reliable platform for autonomous driving technology development as well as for testing purposes, developed in the Intelligent Vehicles Lab at the Technical University of Cartagena. We propose an open and modular architecture capable of easily integrating a wide variety of sensors and actuators which can be used for testing algorithms and control strategies. As a proof of concept, this paper presents a reliable and complete navigation application for a commercial vehicle (Renault Twizy. It comprises a complete perception system (2D LIDAR, 3D HD LIDAR, ToF cameras, Real-Time Kinematic (RTK unit, Inertial Measurement Unit (IMU, an automation of the driving elements of the vehicle (throttle, steering, brakes, and gearbox, a control system, and a decision-making system. Furthermore, two flexible and reliable algorithms are presented for carrying out global and local route planning on board autonomous vehicles.

Optimum balance between innovation and reliability

International Nuclear Information System (INIS)

Negro, B.

2004-01-01

This PowerPoint presentation introduced Gamesa Eolica companies and their industrial capacity, with reference to the product portfolio, market position, main technologies applied, and internationalization. Gamesa has commercial offices in Spain, Germany, Italy, Greece, Portugal, France, and Brazil and is involved in joint ventures with local companies in China, India, Australia, Japan and the United Kingdom. It is a modular vertically integrated company that is involved with wind turbine production, development of wind farms and aeronautic components that include nacelles, blade moulds, root joints, blades, towers, generators and gearboxes. The benefits of modular vertical integration include: quality control in critical components and final product performance; cost competitiveness due to optimized production processes; shorter lead times in the market; and, product reliability. Gamesa Eolica will invest in new production centres in the United States and Europe in 2004 in response to demands for new multi-megawatt wind turbines. tabs., figs

The DOE Next-Generation Drivetrain for Wind Turbine Applications: Gearbox, Generator, and Advanced Si/SiC Hybrid Inverter System: Preprint

Energy Technology Data Exchange (ETDEWEB)

Erdman, William; Keller, Jonathan

2016-08-01

This paper reports on the design and testing results from the U.S. Department of Energy Next-Generation Wind Turbine Drivetrain Project. The drivetrain design reduces the cost of energy by increasing energy capture through drivetrain efficiency improvements; by reducing operation and maintenance costs through reducing gearbox failures; and by lowering capital costs through weight reduction and a series of mechanical and electronic innovations. The paper provides an overview of the drivetrain gearbox and generator and provides a deeper look into the power converter system. The power converter has a number of innovations including the use of hybrid silicon (Si)/silicon carbide (SiC) isolated baseplate switching modules. Switching energies are compared between SiC and Si PIN diodes. The efficiency improvement by use of the SiC diode in a three-level converter is also described. Finally, a brief discussion covering utility interconnect requirements for turbines is provided with a particular focus on utility events that lead to high transient torque loads on drivetrain mechanical elements.

Gearbox Fatigue Load Estimation for Condition Monitoring of Wind Turbines

DEFF Research Database (Denmark)

Perisic, Nevena; Pedersen, Bo Juul; Kirkegaard, Poul Henning

2012-01-01

control and data acquisition (SCADA) system. Estimated loads can be further used for prediction of remaining operating lifetime of turbine components, detection of high stress level or fault detection. An augmented Kalman filter is chosen as the fatigue load estimator because its characteristics well suit......The focus of the paper is on a design of a fatigue load estimator for predictive condition monitoring systems (CMS) of wind turbines. In order to avoid high-price measurement equipment required for direct load measuring, an indirect approach is suggested using only measurements from supervisory...... for the real time application. This paper presents results of the estimation of the gearbox fatigue load, often called shaft torque, using simulated data of wind turbine. Noise sensitivity of the algorithm is investigated by assuming different levels of measurement noise. Shaft torque estimations are compared...

Advanced Propfan Engine Technology (APET) and Single-rotation Gearbox/Pitch Change Mechanism

Science.gov (United States)

Sargisson, D. F.

1985-01-01

The projected performance, in the 1990's time period, of the equivalent technology level high bypass ratio turbofan powered aircraft (at the 150 passenger size) is compared with advanced turboprop propulsion systems. Fuel burn analysis, economic analysis, and pollution (noise, emissions) estimates were made. Three different cruise Mach numbers were investigated for both the turbofan and the turboprop systems. Aerodynamic design and performance estimates were made for nacelles, inlets, and exhaust systems. Air to oil heat exchangers were investigated for oil cooling advanced gearboxes at the 12,500 SHP level. The results and conclusions are positive in that high speed turboprop aircraft will exhibit superior fuel burn characteristics and lower operating costs when compared with equivalent technology turbofan aircraft.

Structural Testing of the Blade Reliability Collaborative Effect of Defect Wind Turbine Blades

Energy Technology Data Exchange (ETDEWEB)

Desmond, M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hughes, S. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Paquette, J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-06-08

Two 8.3-meter (m) wind turbine blades intentionally constructed with manufacturing flaws were tested to failure at the National Wind Technology Center (NWTC) at the National Renewable Energy Laboratory (NREL) south of Boulder, Colorado. Two blades were tested; one blade was manufactured with a fiberglass spar cap and the second blade was manufactured with a carbon fiber spar cap. Test loading primarily consisted of flap fatigue loading of the blades, with one quasi-static ultimate load case applied to the carbon fiber spar cap blade. Results of the test program were intended to provide the full-scale test data needed for validation of model and coupon test results of the effect of defects in wind turbine blade composite materials. Testing was part of the Blade Reliability Collaborative (BRC) led by Sandia National Laboratories (SNL). The BRC seeks to develop a deeper understanding of the causes of unexpected blade failures (Paquette 2012), and to develop methods to enable blades to survive to their expected operational lifetime. Recent work in the BRC includes examining and characterizing flaws and defects known to exist in wind turbine blades from manufacturing processes (Riddle et al. 2011). Recent results from reliability databases show that wind turbine rotor blades continue to be a leading contributor to turbine downtime (Paquette 2012).

Validity and reliability of a new instrument for the evaluation of dental collaboration in disabled people

Directory of Open Access Journals (Sweden)

Scilla Sparabombe

2013-10-01

Full Text Available Background: nowadays, oral health in people with disabilities is an important topic. The phsychological and behavioural problems of these people, their difficulties with environmental adaptations and the absence of any traditional communication determine the compliance needed for treatment The aim of this work was to test the validity and reliability of an original questionnaire that could become an instrument assessing the individual features in people with mental retardation and other developmental disabilities at the time of dental treatment.Methods: it was created a questionnaire with standardised answers regarding four specific areas: neuropsychology, emotional-affect, autonomy and environmental resources. The questionnaire was completed by 63 patients from three different institutes (two rehabilitation institutes and an Institute of Dentistry for patients with special needs. To analyse the answers, each item was transformed into a numeric value. A value of 1 was displayed as the minimum while 4 represented full possession of the considered skills. A total of 17 variables were analysed with descriptive statistics and multivariate analysis. Internal consistency reliability was measured using Cronbach’s alpha. Furthermore, an analysis on convergent/discriminant validity was provided.Results: all variables were positively correlated. The most significant were “guidance”, “communication”, “sociability”, “view”, “hearing” and “feeding”. Items like “self-control”, “equanimity”, “problematic behaviour”, “extroversion” and “autonomy” offered vague and less significant information in identifying the patient’s collaboration level. Variables like “evaluation by the compiler about the patient’s collaboration”, “previous dental experiences” and “attendant” were confirmed. Cronbach’s alpha was 0.77 (standardized result, which meet the a priori criterion of 0.90≥alpha≥0.70.Conclusions

Real-Time Order Tracking of Gear Mesh Vibration in High Speed Planetary Gearboxes

Directory of Open Access Journals (Sweden)

Plöger Daniel Fritz

2018-01-01

Full Text Available Possible approaches to real-time order tracking are discussed. Two methods for real-time order tracking are developed and validated experimentally for the entire audible spectrum. An adaptive heterodyne filter bank is compared to a direct integral transform. The performance of both methods is adequate for usage in an active vibration control (AVC algorithm. Vold-Kalman filters are not suitable for AVC. The vibration data of three different planetary gearboxes is analyzed using order tracking. While some of the existing research could be reproduced, the data contradicts statements made by several authors. Lastly, the architecture of a novel AVC algorithm is sketched out.

An Improved Rigid Multibody Model for the Dynamic Analysis of the Planetary Gearbox in a Wind Turbine

Directory of Open Access Journals (Sweden)

Wenguang Yang

2016-01-01

Full Text Available This paper proposes an improved rigid multibody model for the dynamic analysis of the planetary gearbox in a wind turbine. The improvements mainly include choosing the inertia frame as the reference frame of the carrier, the ring, and the sun and adding a new degree of freedom for each planet. An element assembly method is introduced to build the model, and a time-varying mesh stiffness model is presented. A planetary gear study case is employed to verify the validity of the improved model. Comparisons between the improvement model and the traditional model show that the natural characteristics are very close; the improved model can obtain the right equivalent moment of inertia of the planetary gear in the transient simulation, and all the rotation speeds satisfy the transmission relationships well; harmonic resonance and resonance modulation phenomena can be found in their vibration signals. The improved model is applied in a multistage gearbox dynamics analysis to reveal the prospects of the model. Modal analysis and transient analysis with and without time-varying mesh stiffness considered are conducted. The rotation speeds from the transient analysis are consistent with the theory, and resonance modulation can be found in the vibration signals.

Reliability optimization using multiobjective ant colony system approaches

International Nuclear Information System (INIS)

Zhao Jianhua; Liu Zhaoheng; Dao, M.-T.

2007-01-01

The multiobjective ant colony system (ACS) meta-heuristic has been developed to provide solutions for the reliability optimization problem of series-parallel systems. This type of problems involves selection of components with multiple choices and redundancy levels that produce maximum benefits, and is subject to the cost and weight constraints at the system level. These are very common and realistic problems encountered in conceptual design of many engineering systems. It is becoming increasingly important to develop efficient solutions to these problems because many mechanical and electrical systems are becoming more complex, even as development schedules get shorter and reliability requirements become very stringent. The multiobjective ACS algorithm offers distinct advantages to these problems compared with alternative optimization methods, and can be applied to a more diverse problem domain with respect to the type or size of the problems. Through the combination of probabilistic search, multiobjective formulation of local moves and the dynamic penalty method, the multiobjective ACSRAP, allows us to obtain an optimal design solution very frequently and more quickly than with some other heuristic approaches. The proposed algorithm was successfully applied to an engineering design problem of gearbox with multiple stages

A Smart Collaborative Routing Protocol for Reliable Data Diffusion in IoT Scenarios.

Science.gov (United States)

Ai, Zheng-Yang; Zhou, Yu-Tong; Song, Fei

2018-06-13

It is knotty for current routing protocols to meet the needs of reliable data diffusion during the Internet of Things (IoT) deployments. Due to the random placement, limited resources and unattended features of existing sensor nodes, the wireless transmissions are easily exposed to unauthorized users, which becomes a vulnerable area for various malicious attacks, such as wormhole and Sybil attacks. However, the scheme based on geographic location is a suitable candidate to defend against them. This paper is inspired to propose a smart collaborative routing protocol, Geographic energy aware routing and Inspecting Node (GIN), for guaranteeing the reliability of data exchanging. The proposed protocol integrates the directed diffusion routing, Greedy Perimeter Stateless Routing (GPSR), and the inspecting node mechanism. We first discuss current wireless routing protocols from three diverse perspectives (improving transmission rate, shortening transmission range and reducing transmission consumption). Then, the details of GIN, including the model establishment and implementation processes, are presented by means of the theoretical analysis. Through leveraging the game theory, the inspecting node is elected to monitor the network behaviors. Thirdly, we evaluate the network performances, in terms of transmission delay, packet loss ratio, and throughput, between GIN and three traditional schemes (i.e., Flooding, GPSR, and GEAR). The simulation results illustrate that the proposed protocol is able to outperform the others.

Reliable Collaborative Filtering on Spatio-Temporal Privacy Data

Directory of Open Access Journals (Sweden)

Zhen Liu

2017-01-01

Full Text Available Lots of multilayer information, such as the spatio-temporal privacy check-in data, is accumulated in the location-based social network (LBSN. When using the collaborative filtering algorithm for LBSN location recommendation, one of the core issues is how to improve recommendation performance by combining the traditional algorithm with the multilayer information. The existing approaches of collaborative filtering use only the sparse user-item rating matrix. It entails high computational complexity and inaccurate results. A novel collaborative filtering-based location recommendation algorithm called LGP-CF, which takes spatio-temporal privacy information into account, is proposed in this paper. By mining the users check-in behavior pattern, the dataset is segmented semantically to reduce the data size that needs to be computed. Then the clustering algorithm is used to obtain and narrow the set of similar users. User-location bipartite graph is modeled using the filtered similar user set. Then LGP-CF can quickly locate the location and trajectory of users through message propagation and aggregation over the graph. Through calculating users similarity by spatio-temporal privacy data on the graph, we can finally calculate the rating of recommendable locations. Experiments results on the physical clusters indicate that compared with the existing algorithms, the proposed LGP-CF algorithm can make recommendations more accurately.

Flexible, Secure, and Reliable Data Sharing Service Based on Collaboration in Multicloud Environment

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Qiang Wei

2018-01-01

Full Text Available Due to the abundant storage resources and high reliability data service of cloud computing, more individuals and enterprises are motivated to outsource their data to public cloud platform and enable legal data users to search and download what they need in the outsourced dataset. However, in “Paid Data Sharing” model, some valuable data should be encrypted before outsourcing for protecting owner’s economic benefits, which is an obstacle for flexible application. Specifically, if the owner does not know who (user will download which data files in advance and even does not know the attributes of user, he/she has to either remain online all the time or import a trusted third party (TTP to distribute the file decryption key to data user. Obviously, making the owner always remain online is too inflexible, and wholly depending on the security of TTP is a potential risk. In this paper, we propose a flexible, secure, and reliable data sharing scheme based on collaboration in multicloud environment. For securely and instantly providing data sharing service even if the owner is offline and without TTP, we distribute all encrypted split data/key blocks together to multiple cloud service providers (CSPs, respectively. An elaborate cryptographic protocol we designed helps the owner verify the correctness of data exchange bills, which is directly related to the owner’s economic benefits. Besides, in order to support reliable data service, the erasure-correcting code technic is exploited for tolerating multiple failures among CSPs, and we offer a secure keyword search mechanism that makes the system more close to reality. Extensive security analyses and experiments on real-world data show that our scheme is secure and efficient.

Experimental Characterization of a Grid-Loss Event on a 2.5-MW Dynamometer Using Advanced Operational Modal Analysis: Preprint

Energy Technology Data Exchange (ETDEWEB)

Helsen, J.; Weijtjens, W.; Guo, Y.; Keller, J.; McNiff, B.; Devriendt, C.; Guillaume, P.

2015-02-01

This paper experimentally investigates a worst case grid loss event conducted on the National Renewable Energy Laboratory (NREL) Gearbox Reliability Collaborative (GRC) drivetrain mounted on the 2.5MW NREL dynamic nacelle test-rig. The GRC drivetrain has a directly grid-coupled, fixed speed asynchronous generator. The main goal is the assessment of the dynamic content driving this particular assess the dynamic content of the high-speed stage of the GRC gearbox. In addition to external accelerometers, high frequency sampled measurements of strain gauges were used to assess torque fluctuations and bending moments both at the nacelle main shaft and gearbox high-speed shaft (HSS) through the entire duration of the event. Modal analysis was conducted using a polyreference Least Squares Complex Frequency-domain (pLSCF) modal identification estimator. The event driving the torsional resonance was identified. Moreover, the pLSCF estimator identified main drivetrain resonances based on a combination of acceleration and strain measurements. Without external action during the grid-loss event, a mode shape characterized by counter phase rotation of the rotor and generator rotor determined by the drivetrain flexibility and rotor inertias was the main driver of the event. This behavior resulted in significant torque oscillations with large amplitude negative torque periods. Based on tooth strain measurements of the HSS pinion, this work showed that at each zero-crossing, the teeth lost contact and came into contact with the backside flank. In addition, dynamic nontorque loads between the gearbox and generator at the HSS played an important role, as indicated by strain gauge-measurements.

An Adaptive Multi-Sensor Data Fusion Method Based on Deep Convolutional Neural Networks for Fault Diagnosis of Planetary Gearbox

Science.gov (United States)

Jing, Luyang; Wang, Taiyong; Zhao, Ming; Wang, Peng

2017-01-01

A fault diagnosis approach based on multi-sensor data fusion is a promising tool to deal with complicated damage detection problems of mechanical systems. Nevertheless, this approach suffers from two challenges, which are (1) the feature extraction from various types of sensory data and (2) the selection of a suitable fusion level. It is usually difficult to choose an optimal feature or fusion level for a specific fault diagnosis task, and extensive domain expertise and human labor are also highly required during these selections. To address these two challenges, we propose an adaptive multi-sensor data fusion method based on deep convolutional neural networks (DCNN) for fault diagnosis. The proposed method can learn features from raw data and optimize a combination of different fusion levels adaptively to satisfy the requirements of any fault diagnosis task. The proposed method is tested through a planetary gearbox test rig. Handcraft features, manual-selected fusion levels, single sensory data, and two traditional intelligent models, back-propagation neural networks (BPNN) and a support vector machine (SVM), are used as comparisons in the experiment. The results demonstrate that the proposed method is able to detect the conditions of the planetary gearbox effectively with the best diagnosis accuracy among all comparative methods in the experiment. PMID:28230767

A Two-Stage Diagnosis Framework for Wind Turbine Gearbox Condition Monitoring

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Janet M. Twomey

2013-01-01

Full Text Available Advances in high performance sensing technologies enable the development of wind turbine condition monitoring system to diagnose and predict the system-wide effects of failure events. This paper presents a vibration-based two stage fault detection framework for failure diagnosis of rotating components in wind turbines. The proposed framework integrates an analytical defect detection method and a graphical verification method together to ensure the diagnosis efficiency and accuracy. The efficacy of the proposed methodology is demonstrated with a case study with the gearbox condition monitoring Round Robin study dataset provided by the National Renewable Energy Laboratory (NREL. The developed methodology successfully picked five faults out of seven in total with accurate severity levels without producing any false alarm in the blind analysis. The case study results indicated that the developed fault detection framework is effective for analyzing gear and bearing faults in wind turbine drive train system based upon system vibration characteristics.

EDF/EPRI collaborative program on operator reliability experiments

International Nuclear Information System (INIS)

Villemeur, A.; Meslin, T.; Mosneron, F.; Worledge, D.H.; Joksimovich, V.; Spurgin, A.J.

1988-01-01

Electricite de France (EDF) and Electric Power Research Institute (EPRI) have been involved in human reliability studies over the last few years, in the context of improvements in human reliability assessment (HRA) methodologies, and have been following a systematic process since 1982 which consists of addressing the following five ingredients: - First, classify human interactions into a limited number of classes. - Second, introduce an acceptable framework to organize the application of HRA to PRA studies. - Third, select approach(es) to quantification. - Fourth, test promising models. - Fifth, establish an appropriate data base for tested model(s) with regard to specific applications. EPRI has just recently completed Phase I of the fourth topic. This primarily focused on testing the fundamental hypotheses behing the human cognitive reliability (HCR) correlation, using power plant simulators. EDF has been carrying out simulator studies since 1980, both for man-machine interface validation and HRA data collection. This background of experience provided a stepping stone for the EPRI project. On the other hand, before 1986, EDF had mainly been concentrating on getting qualitative insights from the tests and lacked experience in quantitative analysis and modeling, while EPRI had made advances in this latter area. Before the EPRI Operator Reliability Experiments (ORE) project was initiated, it was abundantly clear to EPRI and EDF that cooperation between the two could be useful and that both parties could gain from the cooperation

Analysis of dynamic meshing characteristic of planetary gear transmission in wind power increasing gearbox

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Wang Jungang

2017-01-01

Full Text Available Dynamic behavior of planetary gear’s tooth contact surface in the different location can better conform operation condition comparing to the general gear pair. Nonlinear finite element algorithm was derived according to the basic control equation of contact dynamics. A finite element model of planetary gear transmission in wind power increasing gearbox was proposed considering different meshing locations based on nonlinear finite element solution. The characteristics of stress distribution at different meshing positions were analyzed. A simulation of the meshing process was conducted using finite element analysis. It was shown that node stresses of external meshing planetary gear varied significantly at different position. The analysis provides some useful insights into the performance of planetary gear’s tooth contact surface.

Aviation Fuel System Reliability and Fail-Safety Analysis. Promising Alternative Ways for Improving the Fuel System Reliability

Directory of Open Access Journals (Sweden)

I. S. Shumilov

2017-01-01

Full Text Available The paper deals with design requirements for an aviation fuel system (AFS, AFS basic design requirements, reliability, and design precautions to avoid AFS failure. Compares the reliability and fail-safety of AFS and aircraft hydraulic system (AHS, considers the promising alternative ways to raise reliability of fuel systems, as well as elaborates recommendations to improve reliability of the pipeline system components and pipeline systems, in general, based on the selection of design solutions.It is extremely advisable to design the AFS and AHS in accordance with Aviation Regulations АП25 and Accident Prevention Guidelines, ICAO (International Civil Aviation Association, which will reduce risk of emergency situations, and in some cases even avoid heavy disasters.ATS and AHS designs should be based on the uniform principles to ensure the highest reliability and safety. However, currently, this principle is not enough kept, and AFS looses in reliability and fail-safety as compared with AHS. When there are the examined failures (single and their combinations the guidelines to ensure the AFS efficiency should be the same as those of norm-adopted in the Regulations АП25 for AHS. This will significantly increase reliability and fail-safety of the fuel systems and aircraft flights, in general, despite a slight increase in AFS mass.The proposed improvements through the use of components redundancy of the fuel system will greatly raise reliability of the fuel system of a passenger aircraft, which will, without serious consequences for the flight, withstand up to 2 failures, its reliability and fail-safety design will be similar to those of the AHS, however, above improvement measures will lead to a slightly increasing total mass of the fuel system.It is advisable to set a second pump on the engine in parallel with the first one. It will run in case the first one fails for some reasons. The second pump, like the first pump, can be driven from the

MODELING OF DYNAMIC PROCESSES IN PLANETARY IN-WHEEL MOTOR GEARBOXES OF MINE TRUCKS DURING ITS STARTING AND ACCELERATION

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V. V. Mikhailov

2012-01-01

Full Text Available The paper describes a mathematical model for planetary double-row in-wheel motor gear box. Main parameters of its dynamic system have been determined in the paper. The paper reveals simulation of transition processes during starting and acceleration of a mine truck with electric motor wheels. Its own gear box frequency has been established theoretically and experimentally in the paper. The paper proposes an algorithm and program for calculations as an alternative to high-cost tests while investigating gear mechanism dynamics of large-size planetary gearboxes.

Fault feature extraction of planet gear in wind turbine gearbox based on spectral kurtosis and time wavelet energy spectrum

Science.gov (United States)

Kong, Yun; Wang, Tianyang; Li, Zheng; Chu, Fulei

2017-09-01

Planetary transmission plays a vital role in wind turbine drivetrains, and its fault diagnosis has been an important and challenging issue. Owing to the complicated and coupled vibration source, time-variant vibration transfer path, and heavy background noise masking effect, the vibration signal of planet gear in wind turbine gearboxes exhibits several unique characteristics: Complex frequency components, low signal-to-noise ratio, and weak fault feature. In this sense, the periodic impulsive components induced by a localized defect are hard to extract, and the fault detection of planet gear in wind turbines remains to be a challenging research work. Aiming to extract the fault feature of planet gear effectively, we propose a novel feature extraction method based on spectral kurtosis and time wavelet energy spectrum (SK-TWES) in the paper. Firstly, the spectral kurtosis (SK) and kurtogram of raw vibration signals are computed and exploited to select the optimal filtering parameter for the subsequent band-pass filtering. Then, the band-pass filtering is applied to extrude periodic transient impulses using the optimal frequency band in which the corresponding SK value is maximal. Finally, the time wavelet energy spectrum analysis is performed on the filtered signal, selecting Morlet wavelet as the mother wavelet which possesses a high similarity to the impulsive components. The experimental signals collected from the wind turbine gearbox test rig demonstrate that the proposed method is effective at the feature extraction and fault diagnosis for the planet gear with a localized defect.

Synthesis and design of a fully integrated multi-topology switched capacitor DC-DC converter with gearbox control

DEFF Research Database (Denmark)

Davidsen, Jeppe Gaardsted; Yosef-Hay, Yoni; Larsen, Dennis Øland

2017-01-01

This paper discusses a methodology of minimizing the amount of switches in a multi-topology fully integrated switched capacitor dc-dc converter powered by a super capacitor for energy harvesting purposes. The design of a simple controlling circuit for the multi-topology power stage using a gearbox...... approach is presented with all the required circuits. The converter is able to generate a output voltage of 1.2 V from a 470 mF capacitor charged to 3 V down to 1.4 V. The output voltage is regulated with a ripple voltage below 7 mV. The controlling circuit including buffers with ideal comparators has...

Tacholess order-tracking approach for wind turbine gearbox fault detection

Institute of Scientific and Technical Information of China (English)

Yi WANG; Yong XIE; Guanghua XU; Sicong ZHANG; Chenggang HOU

2017-01-01

Monitoring of wind turbines under variablespeed operating conditions has become an important issue in recent years.The gearbox of a wind turbine is the most important transmission unit;it generally exhibits complex vibration signatures due to random variations in operating conditions.Spectral analysis is one of the main approaches in vibration signal processing.However,spectral analysis is based on a stationary assumption and thus inapplicable to the fault diagnosis of wind turbines under variable-speed operating conditions.This constraint limits the application of spectral analysis to wind turbine diagnosis in industrial applications.Although order-tracking methods have been proposed for wind turbine fault detection in recent years,current methods are only applicable to cases in which the instantaneous shaft phase is available.For wind turbines with limited structural spaces,collecting phase signals with tachometers or encoders is difficult.In this study,a tacholess order-tracking method for wind turbines is proposed to overcome the limitations of traditional techniques.The proposed method extracts the instantaneous phase from the vibration signal,resamples the signal at equiangular increments,and calculates the order spectrum for wind turbine fault identification.The effectiveness of the proposed method is experimentally validated with the vibration signals of wind turbines.

Tacholess order-tracking approach for wind turbine gearbox fault detection

Science.gov (United States)

Wang, Yi; Xie, Yong; Xu, Guanghua; Zhang, Sicong; Hou, Chenggang

2017-09-01

Monitoring of wind turbines under variable-speed operating conditions has become an important issue in recent years. The gearbox of a wind turbine is the most important transmission unit; it generally exhibits complex vibration signatures due to random variations in operating conditions. Spectral analysis is one of the main approaches in vibration signal processing. However, spectral analysis is based on a stationary assumption and thus inapplicable to the fault diagnosis of wind turbines under variable-speed operating conditions. This constraint limits the application of spectral analysis to wind turbine diagnosis in industrial applications. Although order-tracking methods have been proposed for wind turbine fault detection in recent years, current methods are only applicable to cases in which the instantaneous shaft phase is available. For wind turbines with limited structural spaces, collecting phase signals with tachometers or encoders is difficult. In this study, a tacholess order-tracking method for wind turbines is proposed to overcome the limitations of traditional techniques. The proposed method extracts the instantaneous phase from the vibration signal, resamples the signal at equiangular increments, and calculates the order spectrum for wind turbine fault identification. The effectiveness of the proposed method is experimentally validated with the vibration signals of wind turbines.

Reliability Analysis of Fatigue Failure of Cast Components for Wind Turbines

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Hesam Mirzaei Rafsanjani

2015-04-01

Full Text Available Fatigue failure is one of the main failure modes for wind turbine drivetrain components made of cast iron. The wind turbine drivetrain consists of a variety of heavily loaded components, like the main shaft, the main bearings, the gearbox and the generator. The failure of each component will lead to substantial economic losses such as cost of lost energy production and cost of repairs. During the design lifetime, the drivetrain components are exposed to variable loads from winds and waves and other sources of loads that are uncertain and have to be modeled as stochastic variables. The types of loads are different for offshore and onshore wind turbines. Moreover, uncertainties about the fatigue strength play an important role in modeling and assessment of the reliability of the components. In this paper, a generic stochastic model for fatigue failure of cast iron components based on fatigue test data and a limit state equation for fatigue failure based on the SN-curve approach and Miner’s rule is presented. The statistical analysis of the fatigue data is performed using the Maximum Likelihood Method which also gives an estimate of the statistical uncertainties. Finally, illustrative examples are presented with reliability analyses depending on various stochastic models and partial safety factors.

A signal pre-processing algorithm designed for the needs of hardware implementation of neural classifiers used in condition monitoring

DEFF Research Database (Denmark)

Dabrowski, Dariusz; Hashemiyan, Zahra; Adamczyk, Jan

2015-01-01

Gearboxes have a significant influence on the durability and reliability of a power transmission system. Currently, extensive research studies are being carried out to increase the reliability of gearboxes working in the energy industry, especially with a focus on planetary gears in wind turbines...... is to estimate the features of a vibration signal that are related to failures, e.g. misalignment and unbalance. These features can serve as the components of an input vector for a neural classifier. The approach proposed here has several important benefits: it is resistant to small speed fluctuations up to 7...

Gearbox fault diagnosis based on time-frequency domain synchronous averaging and feature extraction technique

Science.gov (United States)

Zhang, Shengli; Tang, Jiong

2016-04-01

Gearbox is one of the most vulnerable subsystems in wind turbines. Its healthy status significantly affects the efficiency and function of the entire system. Vibration based fault diagnosis methods are prevalently applied nowadays. However, vibration signals are always contaminated by noise that comes from data acquisition errors, structure geometric errors, operation errors, etc. As a result, it is difficult to identify potential gear failures directly from vibration signals, especially for the early stage faults. This paper utilizes synchronous averaging technique in time-frequency domain to remove the non-synchronous noise and enhance the fault related time-frequency features. The enhanced time-frequency information is further employed in gear fault classification and identification through feature extraction algorithms including Kernel Principal Component Analysis (KPCA), Multilinear Principal Component Analysis (MPCA), and Locally Linear Embedding (LLE). Results show that the LLE approach is the most effective to classify and identify different gear faults.

Model-Based Load Estimation for Predictive Condition Monitoring of Wind Turbines

DEFF Research Database (Denmark)

Perisic, Nevena; Pederen, Bo Juul; Grunnet, Jacob Deleuran

signal is performed online, and a Load Indicator Signal (LIS) is formulated as a ratio between current estimated accumulated fatigue loads and its expected value based only on a priori knowledge (WTG dynamics and wind climate). LOT initialisation is based on a priori knowledge and can be obtained using...... programme for pre-maintenance actions. The performance of LOT is demonstrated by applying it to one of the most critical WTG components, the gearbox. Model-based load CMS for gearbox requires only standard WTG SCADA data. Direct measuring of gearbox fatigue loads requires high cost and low reliability...... measurement equipment. Thus, LOT can significantly reduce the price of load monitoring....

Dynamic modeling and analysis of load sharing characteristics of wind turbine gearbox

Directory of Open Access Journals (Sweden)

Pengxing Yi

2015-03-01

Full Text Available A coupled dynamic model, which contains helical gears-shafts-bearings for a wind turbine gearbox transmission system, was built considering nonlinear factors of the time-varying mesh stiffness, the external varying load, and the dynamic transmission error at first. The model is confirmed to be right after comparing the theoretical data with the experimental load sharing values, and also it is found that the static load sharing is conservative to evaluate the non-equilibrium effect of a planetary gear system. Besides, the analyzing results of the influence of average error and amplitude error on the load sharing show that the load sharing could be decreased if the error goes up a little. Then, by means of treating the static tracing point as the dynamic initial values, we analyzed the initial position’s influence on the load sharing of transmission system to provide a theoretical basis of load sharing control. Furthermore, we explored the influence of high-speed shaft position angle on the load sharing and the dynamic load factor of gears fixed on the parallel shafts. The results provide useful theoretical guidelines for the design of parallel shaft gear system in the wind turbines.

Children's Hospitals' Solutions for Patient Safety Collaborative Impact on Hospital-Acquired Harm.

Science.gov (United States)

Lyren, Anne; Brilli, Richard J; Zieker, Karen; Marino, Miguel; Muething, Stephen; Sharek, Paul J

2017-09-01

To determine if an improvement collaborative of 33 children's hospitals focused on reliable best practice implementation and culture of safety improvements can reduce hospital-acquired conditions (HACs) and serious safety events (SSEs). A 3-year prospective cohort study design with a 12-month historical control population was completed by the Children's Hospitals' Solutions for Patient Safety collaborative. Identification and dissemination of best practices related to 9 HACs and SSE reduction focused on key process and culture of safety improvements. Individual hospital improvement teams leveraged the resources of a large, structured children's hospital collaborative using electronic, virtual, and in-person interactions. Thirty-three children's hospitals from across the United States volunteered to be part of the Children's Hospitals' Solutions for Patient Safety collaborative. Thirty-two met all the data submission eligibility requirements for the HAC improvement objective of this study, and 21 participated in the high-reliability culture work aimed at reducing SSEs. Significant harm reduction occurred in 8 of 9 common HACs (range 9%-71%; P collaborative dedicated to implementing HAC-related best-practice prevention bundles and culture of safety interventions designed to increase the use of high-reliability organization practices resulted in significant HAC and SSE reductions. Structured collaboration and rapid sharing of evidence-based practices and tools are effective approaches to decreasing hospital-acquired harm. Copyright © 2017 by the American Academy of Pediatrics.

Existing machine propulsion is transformed by state-of-the-art gearbox apparatus saves at least 50% energy

Science.gov (United States)

Abramov, V.

2013-12-01

This innovation on www.repowermachine.com is finalist at Clean-tech and Energy of 2012 Minnesota's TEKNE AWARDS. Vehicles are pushed by force of friction between their wheels and land, propellers and water or air according to Third Newton's law of physics of moving. Force of friction is dependent to vehicle weight as highest torque of wheel or propeller for vehicle moving from stop. Friction force DOES NOT dependent to motor power. Why existing SUV of 2,000 lb uses 550 hp motor when first vehicle has 0.75 hp motor (Carl Benz';s patent #37435, January 29, 1886 in Germany)? Gas or magnet field reaches needed torque of wheels too slowly because requires huge motor power for acceleration SUV from 0 to 100 mph for 5 second. The acceleration system by gas or magnet field uses additional energy for increasing motor shaft idle speed and reduces its highest torque of physical volume because necessary to increase motor power that equal/exceed motor power according to vehicle weight. Therefore, any transmission torque DOES NOT NEED and it is use as second brake. Ship, locomotives, helicopters, CNC machine tools, etc motor(s) directly turn wheels, propellers, spindles or ignore to use gear -transmission designs. How do you follow to Creator's physics law of LEVER for saving energy? Existing machine propulsion is transformed by one comprising least numbers of gears and maybe shafts from above state-of-the-art 1,000 gearbox apparatus designs. It is installed or replaced transmission in existing propulsion that is transformed to non-accelerated propulsion. It cuts about 80% mechanical energy that acceleration system wastes in motor heat form, cuts time of movement by reaching each speed for 1-2 seconds. It produces all needed speeds and uses only idle speed of cheapest motor with reduced power and cost that have replaced existing motor too. There is opportunity to eliminate vehicle/machine roads traffics in cities that creates additional unknown GHG emissions Revolutionary

Validation of the Physician-Pharmacist Collaborative Index for physicians in Malaysia.

Science.gov (United States)

Sellappans, Renukha; Ng, Chirk Jenn; Lai, Pauline Siew Mei

2015-12-01

Establishing a collaborative working relationship between doctors and pharmacists is essential for the effective provision of pharmaceutical care. The Physician-Pharmacist Collaborative Index (PPCI) was developed to assess the professional exchanges between doctors and pharmacists. Two versions of the PPCI was developed: one for physicians and one for pharmacists. However, these instruments have not been validated in Malaysia. To determine the validity and reliability of the PPCI for physicians in Malaysia. An urban tertiary hospital in Malaysia. This prospective study was conducted from June to August 2014. Doctors were grouped as either a "collaborator" or a "non-collaborator". Collaborators were doctors who regularly worked with one particular clinical pharmacist in their ward, while non-collaborators were doctors who interacted with any random pharmacist who answered the general pharmacy telephone line whenever they required assistance on medication-related enquiries, as they did not have a clinical pharmacist in their ward. Collaborators were firstly identified by the clinical pharmacist he/she worked with, then invited to participate in this study through email, as it was difficult to locate and approach them personally. Non-collaborators were sampled conveniently by approaching them in person as these doctors could be easily sampled from any wards without a clinical pharmacist. The PPCI for physicians was administered at baseline and 2 weeks later. Validity (face validity, factor analysis and discriminative validity) and reliability (internal consistency and test-retest) of the PPCI for physicians. A total of 116 doctors (18 collaborators and 98 non-collaborators) were recruited. Confirmatory factor analysis confirmed that the PPCI for physicians was a 3-factor model. The correlation of the mean domain scores ranged from 0.711 to 0.787. "Collaborators" had significantly higher scores compared to "non-collaborators" (81.4 ± 10.1 vs. 69.3 ± 12.1, p Malaysia.

Vibration Sideband Modulations and Harmonics Separation of a Planetary Helicopter Gearbox with Two Different Configurations

Directory of Open Access Journals (Sweden)

Nader Sawalhi

2016-01-01

Full Text Available This paper examines the spectrum and cepstrum content of vibration signals taken from a helicopter gearbox with two different configurations (3 and 4 planets. It presents a signal processing algorithm to separate synchronous and nonsynchronous components for complete shafts’ harmonic extraction and removal. The spectrum and cepstrum of the vibration signal for two configurations are firstly analyzed and discussed. The effect of changing the number of planets on the fundamental gear mesh frequency (epicyclic mesh frequency and its sidebands is discussed. The paper explains the differences between the two configurations and discusses, in particular, the asymmetry of the modulation sidebands about the epicyclic mesh frequency in the 4 planets arrangement. Finally a separation algorithm, which is based on resampling the order-tracked signal to have an integer number of samples per revolution for a specific shaft, is proposed for a complete removal of the shafts harmonics. The results obtained from the presented separation algorithms are compared to other separation schemes such as discrete random separation (DRS and time synchronous averaging (TSA with clear improvements and better results.

Outcomes of interprofessional collaboration for hospitalized cancer patients.

Science.gov (United States)

San Martin-Rodriguez, Leticia; D'Amour, Danielle; Leduc, Nicole

2008-01-01

This study aims to evaluate the effect of the intensity of interprofessional collaboration on hospitalized cancer patients. We conducted a cross-sectional study of 312 patients to examine the effects of intensity of interprofessional collaboration (low vs high intensity collaboration) on patient satisfaction, uncertainty, pain management, and length of stay. Data on the intensity of interprofessional collaboration, patient satisfaction, and uncertainty were collected from professionals and patients using valid and reliable instruments. Administrative and clinical records were used to calculate the index of pain management and length of hospital stay. The analysis revealed the existence of significant differences between patients who are cared for by teams operating with a high intensity of collaboration and those who are cared for by teams operating with a low intensity of collaboration, as measured by the mean satisfaction (P management (P = .047). The analysis also found no significant difference (P = .217) in their length of hospital stay. The findings suggest that intensity of interprofessional collaboration has a positive effect on patient satisfaction, reduces uncertainty, and improves pain management, yet they also suggest that the degree of collaboration does not influence the length of hospital stay.

Reliability Based Ship Structural Design

DEFF Research Database (Denmark)

Dogliani, M.; Østergaard, C.; Parmentier, G.

1996-01-01

This paper deals with the development of different methods that allow the reliability-based design of ship structures to be transferred from the area of research to the systematic application in current design. It summarises the achievements of a three-year collaborative research project dealing...... with developments of models of load effects and of structural collapse adopted in reliability formulations which aim at calibrating partial safety factors for ship structural design. New probabilistic models of still-water load effects are developed both for tankers and for containerships. New results are presented...... structure of several tankers and containerships. The results of the reliability analysis were the basis for the definition of a target safety level which was used to asses the partial safety factors suitable for in a new design rules format to be adopted in modern ship structural design. Finally...

The importance of collaboration in the advancement of current and next generation reactors

International Nuclear Information System (INIS)

Jackson, Kate; Goossen, John; Anness, Mike; Meston, Tom

2010-01-01

The sections of the contribution are as follows: Tradition of innovation. Growing demand for nuclear power; Collaboration drivers; Responses. Knowledge transfer and management is critical. What kind of focus? Equipment reliability. Advanced repair, replacement and construction approaches. Materials. Plant safety margins. Spent fuel management. Examples of European collaboration. Zorita materials examination. Collaboration in the development of next generation reactors; Westinghouse R and D priorities; A look to the future. (P.A.)

Collaborative Learning Indicators as Determinants of Social Well ...

African Journals Online (AJOL)

This study investigated collaborative learning indicators as predictors of social well-being among female undergraduates in the University of Abuja, Abuja, Nigeria. The study employed correlational research design. A sample of 250 female students was randomly selected within Faculty of Education. Three reliable ...

Advanced tools for enhancing control room collaborations

International Nuclear Information System (INIS)

Abla, G.; Flanagan, S.M.; Peng, Q.; Burruss, J.R.; Schissel, D.P.

2006-01-01

The US National Fusion Collaboratory (NFC) project has been exploring a variety of computer and network technologies to develop a persistent, efficient, reliable and convenient collaborative environment for magnetic fusion research. One goal is to enhance remote and collocated team collaboration by integrating collaboration software tools into control room operations as well as with data analysis tools. To achieve this goal, the NFC recently introduced two new collaboration technologies into the DIII-D tokamak control room. The first technology is a high-resolution, large format Shared Display Wall (SDW). By creating a shared public display space and providing real time visual information about the multiple aspects of complex experiment activity, the large SDW plays an important role in increasing the rate of information dissemination and promoting interaction among team members. The second technology being implemented is the 'tokamak control room aware' Instant Messaging (IM) service. In addition to providing text-chat capabilities for research scientists, it enables them to automatically receive information about experiment operations and data analysis processes to remotely monitor the status of ongoing tokamak experiment. As a result, the IM service has become a unified portal interface for team collaboration and remote participation

Advanced tools for enhancing control room collaborations

Energy Technology Data Exchange (ETDEWEB)

Abla, G. [General Atomics, P.O. Box 85608, San Diego, CA 92186 5608 (United States)]. E-mail: abla@fusion.gat.com; Flanagan, S.M. [General Atomics, P.O. Box 85608, San Diego, CA 92186 5608 (United States); Peng, Q. [General Atomics, P.O. Box 85608, San Diego, CA 92186 5608 (United States); Burruss, J.R. [General Atomics, P.O. Box 85608, San Diego, CA 92186 5608 (United States); Schissel, D.P. [General Atomics, P.O. Box 85608, San Diego, CA 92186 5608 (United States)

2006-07-15

The US National Fusion Collaboratory (NFC) project has been exploring a variety of computer and network technologies to develop a persistent, efficient, reliable and convenient collaborative environment for magnetic fusion research. One goal is to enhance remote and collocated team collaboration by integrating collaboration software tools into control room operations as well as with data analysis tools. To achieve this goal, the NFC recently introduced two new collaboration technologies into the DIII-D tokamak control room. The first technology is a high-resolution, large format Shared Display Wall (SDW). By creating a shared public display space and providing real time visual information about the multiple aspects of complex experiment activity, the large SDW plays an important role in increasing the rate of information dissemination and promoting interaction among team members. The second technology being implemented is the 'tokamak control room aware' Instant Messaging (IM) service. In addition to providing text-chat capabilities for research scientists, it enables them to automatically receive information about experiment operations and data analysis processes to remotely monitor the status of ongoing tokamak experiment. As a result, the IM service has become a unified portal interface for team collaboration and remote participation.

Psychometrics of the scale of attitudes toward physician-pharmacist collaboration: a study with medical students.

Science.gov (United States)

Hojat, Mohammadreza; Spandorfer, John; Isenberg, Gerald A; Vergare, Michael J; Fassihi, Reza; Gonnella, Joseph S

2012-01-01

Despite the emphasis placed on interdisciplinary education and interprofessional collaboration between physicians and pharmacologists, no psychometrically sound instrument is available to measure attitudes toward collaborative relationships. This study was designed to examine psychometrics of an instrument for measuring attitudes toward physician-pharmacist collaborative relationships for administration to students in medical and pharmacy schools and to physicians and pharmacists. The Scale of Attitudes Toward Physician-Pharmacist Collaboration was completed by 210 students at Jefferson Medical College. Factor analysis and correlational methods were used to examine psychometrics of the instrument. Consistent with the conceptual framework of interprofessional collaboration, three underlying constructs, namely "responsibility and accountability;" "shared authority;" and "interdisciplinary education" emerged from the factor analysis of the instrument providing support for its construct validity. The reliability coefficient alpha for the instrument was 0.90. The instrument's criterion-related validity coefficient with scores of a validated instrument (Jefferson Scale of Attitudes Toward Physician-Nurse Collaboration) was 0.70. Findings provide support for the validity and reliability of the instrument for medical students. The instrument has the potential to be used for the evaluation of interdisciplinary education in medical and pharmacy schools, and for the evaluation of patient outcomes resulting from collaborative physician-pharmacist relationships.

Collaboration Layer for Robots in Mobile Ad-hoc Networks

DEFF Research Database (Denmark)

Borch, Ole; Madsen, Per Printz; Broberg, Jacob Honor´e

2009-01-01

networks to solve tasks collaboratively. In this proposal the Collaboration Layer is modelled to handle service and position discovery, group management, and synchronisation among robots, but the layer is also designed to be extendable. Based on this model of the Collaboration Layer, generic services...... are provided to the application running on the robot. The services are generic because they can be used by many different applications, independent of the task to be solved. Likewise, specific services are requested from the underlying Virtual Machine, such as broadcast, multicast, and reliable unicast....... A prototype of the Collaboration Layer has been developed to run in a simulated environment and tested in an evaluation scenario. In the scenario five robots solve the tasks of vacuum cleaning and entrance guarding, which involves the ability to discover potential co-workers, form groups, shift from one group...

Modified complementary ensemble empirical mode decomposition and intrinsic mode functions evaluation index for high-speed train gearbox fault diagnosis

Science.gov (United States)

Chen, Dongyue; Lin, Jianhui; Li, Yanping

2018-06-01

Complementary ensemble empirical mode decomposition (CEEMD) has been developed for the mode-mixing problem in Empirical Mode Decomposition (EMD) method. Compared to the ensemble empirical mode decomposition (EEMD), the CEEMD method reduces residue noise in the signal reconstruction. Both CEEMD and EEMD need enough ensemble number to reduce the residue noise, and hence it would be too much computation cost. Moreover, the selection of intrinsic mode functions (IMFs) for further analysis usually depends on experience. A modified CEEMD method and IMFs evaluation index are proposed with the aim of reducing the computational cost and select IMFs automatically. A simulated signal and in-service high-speed train gearbox vibration signals are employed to validate the proposed method in this paper. The results demonstrate that the modified CEEMD can decompose the signal efficiently with less computation cost, and the IMFs evaluation index can select the meaningful IMFs automatically.

New Collaborative Filtering Algorithms Based on SVD++ and Differential Privacy

OpenAIRE

Xian, Zhengzheng; Li, Qiliang; Li, Gai; Li, Lei

2017-01-01

Collaborative filtering technology has been widely used in the recommender system, and its implementation is supported by the large amount of real and reliable user data from the big-data era. However, with the increase of the users’ information-security awareness, these data are reduced or the quality of the data becomes worse. Singular Value Decomposition (SVD) is one of the common matrix factorization methods used in collaborative filtering, which introduces the bias information of users a...

Collaboration and E-collaboration

DEFF Research Database (Denmark)

Razmerita, Liana; Kirchner, Kathrin

2015-01-01

Understanding student’s perception of collaboration and how collaboration is supported by ICT is important for its efficient use in the classroom. This article aims to investigate how students perceive collaboration and how they use new technologies in collaborative group work. Furthermore......, it tries to measure the impact of technology on students’ satisfaction with collaboration outcomes. In particular, the study aims to address the following research questions: Which demographic information (e.g. gender and place of origin) is significant for collaboration and ecollaboration? and Which...... are the perceived factors that influence the students’ group performance? The findings of this study emphasize that there are gender and cultural differences with respect to the perception of e-collaboration. Furthermore, the article summarizes in a model the most significant factors influencing group performance....

Embedded mechatronic systems 1 analysis of failures, predictive reliability

CERN Document Server

El Hami, Abdelkhalak

2015-01-01

In operation, mechatronics embedded systems are stressed by loads of different causes: climate (temperature, humidity), vibration, electrical and electromagnetic. These stresses in components which induce failure mechanisms should be identified and modeled for better control. AUDACE is a collaborative project of the cluster Mov'eo that address issues specific to mechatronic reliability embedded systems. AUDACE means analyzing the causes of failure of components of mechatronic systems onboard. The goal of the project is to optimize the design of mechatronic devices by reliability. The projec

An exploration of nurse-physician perceptions of collaborative behaviour.

Science.gov (United States)

Collette, Alice E; Wann, Kristen; Nevin, Meredith L; Rique, Karen; Tarrant, Grant; Hickey, Lorraine A; Stichler, Jaynelle F; Toole, Belinda M; Thomason, Tanna

2017-07-01

Interprofessional collaboration is a key element in providing safe, holistic patient care in the acute care setting. Trended data at a community hospital indicated opportunities for improvement in collaboration on micro, meso, and macro levels. The aim of this survey study was to assess the current state of collaboration between frontline nurses and physicians at a non-academic acute care hospital. A convenience sample of participants was recruited with a final respondent sample of 355 nurses and 82 physicians. The results indicated that physicians generally perceived greater collaboration than nurses. Physician ratings did not vary by primary practice area, whereas nurse ratings varied by clinical practice area. Nurse ratings were the lowest in the operating room and the highest in the emergency department. Text-based responses to an open-ended question were analysed by role and coded by two independent research teams. Emergent themes emphasised the importance of rounding, roles, respect, and communication. Despite recognition of the need for improved collaboration and relational behaviours, strategies to improve collaborative practice must be fostered at the meso level by organisational leaders and customised to address micro-level values. At the study site, findings have been used to address and improve collaboration towards the goal of becoming a high reliability organisation.

Can peers rate reliably as experts in small CSCL groups?

DEFF Research Database (Denmark)

Magnisalis, Ioannis; Demetriadis, Stavros; Papadopoulos, Pantelis M.

2016-01-01

Research on the impact of peer rating (PR) has provided encouraging results, as a method to foster collaborative learning and improve its outcomes. The scope of this paper is to discuss peer rating towards two specific directions that usually are neglected in the CSCL field, namely: (a) coaching...... of objective anonymous peer rating through a rubric, and (b) provision of peer rating summary information during collaboration. The case study utilized an asynchronous CSCL tool with the two aforementioned capabilities. Initial results showed that peer rating, when anonymous, and guided, can be as reliable...

Operational reliability testing of FBR fuel in EBR-II

International Nuclear Information System (INIS)

Asaga, Takeo; Ukai, Shigeharu; Nomura, Shigeo; Shikakura, Sakae

1991-01-01

The operational reliability testing of FBR fuel has been conducting in EBR-II as a DOE/PNC collaboration program. This paper reviews the achieved summary of Phase-I test as well as outline of progressing Phase-II test. In Phase-I test, the reliability of FBR fuel pins including 'MONJU' fuel was demonstrated at the event of operational transient. Continued operation of the failed pins was also shown to be feasible without affecting the plant operation. The objectives of the Phase-II test is to extend the data base relating with the operational reliability for long life fuel, and to supply the highly quantitative evaluation. The valuable insight obtained in Phase-II test are considerably expected to be useful toward the achievement of commercial FBR. (author)

Support vector data description for fusion of multiple health indicators for enhancing gearbox fault diagnosis and prognosis

International Nuclear Information System (INIS)

Wang, Dong; Tse, Peter W; Guo, Wei; Miao, Qiang

2011-01-01

A novel method for enhancing gearbox fault diagnosis and prognosis is developed by fusion of multiple health indicators through support vector data description. First, the Comblet transform is used to identify gear residual error signals from the raw signal. Second, based on the observation of gear residual error signals, a total of 11 gear health indicators are identified, and are categorized into two types of indicators. The first and second types of indicators are for fault diagnosis and prognosis, respectively. The first type has six indicators, which are sensitive to impulsive signals triggered by anomalous impacts. The second type has five indicators, which are suitable for tracking degradation of faults. Third, through the support vector data description, the first six health indicators are fused into type one indicators for fault diagnosis. The remaining five indicators are fused into type two indicators for fault prognosis. Finally, a Gaussian kernel is designed to enhance the performance of type one and two indicators by optimal range of width size. The effectiveness of the proposed method is validated through experiments. The new method has been proven to be superior to methods that use unfused indicators individually

Framework for Human-Automation Collaboration: Conclusions from Four Studies

Energy Technology Data Exchange (ETDEWEB)

Oxstrand, Johanna [Idaho National Lab. (INL), Idaho Falls, ID (United States); Le Blanc, Katya L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); O' Hara, John [Brookhaven National Lab. (BNL), Upton, NY (United States); Joe, Jeffrey C. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Whaley, April M. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Medema, Heather [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2013-11-01

The Human Automation Collaboration (HAC) research project is investigating how advanced technologies that are planned for Advanced Small Modular Reactors (AdvSMR) will affect the performance and the reliability of the plant from a human factors and human performance perspective. The HAC research effort investigates the consequences of allocating functions between the operators and automated systems. More specifically, the research team is addressing how to best design the collaboration between the operators and the automated systems in a manner that has the greatest positive impact on overall plant performance and reliability. Oxstrand et al. (2013 - March) describes the efforts conducted by the researchers to identify the research needs for HAC. The research team reviewed the literature on HAC, developed a model of HAC, and identified gaps in the existing knowledge of human-automation collaboration. As described in Oxstrand et al. (2013 – June), the team then prioritized the research topics identified based on the specific needs in the context of AdvSMR. The prioritization was based on two sources of input: 1) The preliminary functions and tasks, and 2) The model of HAC. As a result, three analytical studies were planned and conduced; 1) Models of Teamwork, 2) Standardized HAC Performance Measurement Battery, and 3) Initiators and Triggering Conditions for Adaptive Automation. Additionally, one field study was also conducted at Idaho Falls Power.

Perancangan Sistem Pemeliharaan Menggunakan Metode Reliability Centered Maintenance (RCM Pada Pulverizer (Studi Kasus: PLTU Paiton Unit 3

Directory of Open Access Journals (Sweden)

RATNA BHAKTI PUSPITA SARI

2017-03-01

Full Text Available PLTU Paiton Unit 3 merupakan perusahaan yang bergerak di bidang produksi listrik menggunakan bahan baku batubara yang terletak di Paiton, Probolinggo. Untuk mencapai target, proses produksi dilakukan 24 jam selama 1 tahun tanpa henti. Program pemeliharaan mesin sangat penting untuk kelancaran proses produksi. Dalam rangka mencapai target tersebut dituntut adanya kelancaran batubara dari silo hingga surface burner menggunakan pulverizer. Data dari Departemen Engineering menunjukkan bahwa beberapa subsistem pulverizer sering mengalami kerusakan yang dapat menimbulkan kegagalan pada sistem tersebut. Penelitian tugas akhir ini menggunakan metode Reliability Centered Maintenance (RCM untuk menurunkan tingkat breakdown mesin dan downtime produksi. Data historis kerusakan pulverizer dianalisa. Kemudian kegagalan dari suatu komponen yang dapat menyebabkan kegagalan fungsi dari sistem diidentifikasi menggunakan metode Failure Mode and Effect Analysis (FMEA. Selanjutnya menggunakan RCM Decision Worksheet untuk mengetahui bagian dari sistem yang gagal dan perlu dilakukan tindakan perbaikan dan pencegahan berdasarkan kegagalan yang ada agar kejadian yang sama tidak terulang dan menentukan kegiatan perancang perawatan yang tepat pada setiap komponen Berdasarkan analisis data secara Reliability Centered Maintenance (RCM terdapat 12 failure mode yang terjadi pada pulverizer. 3 failure mode dapat dicegah dengan scheduled restoration task, 8 failure mode dapat dicegah dengan scheduled discard task, dan 1 failure mode dapat dicegah dengan redesign. Analisis kuantitatif menggunakan distribusi kegagalan dengan perangkat lunak Weibull++6 didapatkan MTBF grinding roller 2880,66 jam, MTBF hydraulic pump 5075,06 jam, MTBF gearbox 5381,65 jam dan MTBF coal feeder 525,17 jam.

Product reliability and thin-film photovoltaics

Science.gov (United States)

Gaston, Ryan; Feist, Rebekah; Yeung, Simon; Hus, Mike; Bernius, Mark; Langlois, Marc; Bury, Scott; Granata, Jennifer; Quintana, Michael; Carlson, Carl; Sarakakis, Georgios; Ogden, Douglas; Mettas, Adamantios

2009-08-01

Despite significant growth in photovoltaics (PV) over the last few years, only approximately 1.07 billion kWhr of electricity is estimated to have been generated from PV in the US during 2008, or 0.27% of total electrical generation. PV market penetration is set for a paradigm shift, as fluctuating hydrocarbon prices and an acknowledgement of the environmental impacts associated with their use, combined with breakthrough new PV technologies, such as thin-film and BIPV, are driving the cost of energy generated with PV to parity or cost advantage versus more traditional forms of energy generation. In addition to reaching cost parity with grid supplied power, a key to the long-term success of PV as a viable energy alternative is the reliability of systems in the field. New technologies may or may not have the same failure modes as previous technologies. Reliability testing and product lifetime issues continue to be one of the key bottlenecks in the rapid commercialization of PV technologies today. In this paper, we highlight the critical need for moving away from relying on traditional qualification and safety tests as a measure of reliability and focus instead on designing for reliability and its integration into the product development process. A drive towards quantitative predictive accelerated testing is emphasized and an industrial collaboration model addressing reliability challenges is proposed.

Reliability Analysis of Fatigue Failure of Cast Components for Wind Turbines

OpenAIRE

Hesam Mirzaei Rafsanjani; John Dalsgaard Sørensen

2015-01-01

Fatigue failure is one of the main failure modes for wind turbine drivetrain components made of cast iron. The wind turbine drivetrain consists of a variety of heavily loaded components, like the main shaft, the main bearings, the gearbox and the generator. The failure of each component will lead to substantial economic losses such as cost of lost energy production and cost of repairs. During the design lifetime, the drivetrain components are exposed to variable loads from winds and waves an...

The National Centre of Systems Reliability and some aspects of its future activities

International Nuclear Information System (INIS)

Bourne, A.J.

1975-01-01

The National Centre of Systems Reliability (NCSR) has been set up to enhance the work of the Systems Reliability Service (SRS), which during its four years of operation by the UKAEA has offered to industry expertise in the quantification of reliability of systems in various technological applications. An outline is presented of the background to the establishment of the NCSR, including a brief summary of the work of the SRS. Certain aspects of the future activities of the NCSR particularly in relation to research and collaboration with universities are discussed. (U.K.)

Sensing in the collaborative Internet of Things.

Science.gov (United States)

Borges Neto, João B; Silva, Thiago H; Assunção, Renato Martins; Mini, Raquel A F; Loureiro, Antonio A F

2015-03-19

We are entering a new era of computing technology, the era of Internet of Things (IoT). An important element for this popularization is the large use of off-the-shelf sensors. Most of those sensors will be deployed by different owners, generally common users, creating what we call the Collaborative IoT. This collaborative IoT helps to increase considerably the amount and availability of collected data for different purposes, creating new interesting opportunities, but also several challenges. For example, it is very challenging to search for and select a desired sensor or a group of sensors when there is no description about the provided sensed data or when it is imprecise. Given that, in this work we characterize the properties of the sensed data in the Internet of Things, mainly the sensed data contributed by several sources, including sensors from common users. We conclude that, in order to safely use data available in the IoT, we need a filtering process to increase the data reliability. In this direction, we propose a new simple and powerful approach that helps to select reliable sensors. We tested our method for different types of sensed data, and the results reveal the effectiveness in the correct selection of sensor data.

Sensing in the Collaborative Internet of Things

Directory of Open Access Journals (Sweden)

João B. Borges Neto

2015-03-01

Full Text Available We are entering a new era of computing technology, the era of Internet of Things (IoT. An important element for this popularization is the large use of off-the-shelf sensors. Most of those sensors will be deployed by different owners, generally common users, creating what we call the Collaborative IoT. This collaborative IoT helps to increase considerably the amount and availability of collected data for different purposes, creating new interesting opportunities, but also several challenges. For example, it is very challenging to search for and select a desired sensor or a group of sensors when there is no description about the provided sensed data or when it is imprecise. Given that, in this work we characterize the properties of the sensed data in the Internet of Things, mainly the sensed data contributed by several sources, including sensors from common users. We conclude that, in order to safely use data available in the IoT, we need a filtering process to increase the data reliability. In this direction, we propose a new simple and powerful approach that helps to select reliable sensors. We tested our method for different types of sensed data, and the results reveal the effectiveness in the correct selection of sensor data.

Sensing in the Collaborative Internet of Things

Science.gov (United States)

Borges Neto, João B.; Silva, Thiago H.; Assunção, Renato Martins; Mini, Raquel A. F.; Loureiro, Antonio A. F.

2015-01-01

We are entering a new era of computing technology, the era of Internet of Things (IoT). An important element for this popularization is the large use of off-the-shelf sensors. Most of those sensors will be deployed by different owners, generally common users, creating what we call the Collaborative IoT. This collaborative IoT helps to increase considerably the amount and availability of collected data for different purposes, creating new interesting opportunities, but also several challenges. For example, it is very challenging to search for and select a desired sensor or a group of sensors when there is no description about the provided sensed data or when it is imprecise. Given that, in this work we characterize the properties of the sensed data in the Internet of Things, mainly the sensed data contributed by several sources, including sensors from common users. We conclude that, in order to safely use data available in the IoT, we need a filtering process to increase the data reliability. In this direction, we propose a new simple and powerful approach that helps to select reliable sensors. We tested our method for different types of sensed data, and the results reveal the effectiveness in the correct selection of sensor data. PMID:25808766

Damage preventing measures for wind turbines. Phase 1- Reliability data

Energy Technology Data Exchange (ETDEWEB)

Carlsson, Fredrik; Eriksson, Emil; Dahlberg, Magnus

2010-08-15

The state of existing reliability and failure data in the public sources has been investigated. The prime goal has been to evaluate the data's usefulness for developing damage preventing measures. Some publicly available databases exist, and the data has been presented in several papers in the literature. The results from the investigation can seem quite negative. Detailed data are lacking and the level of detailed reporting has even been decreasing in recent years. Information on the impact of load condition on failures, which is an important question, are lacking throughout in the statistics. Some components dominate the failure statistics. These are for example the gearboxes, where failures lead to long down times. Failures of the electrical system lead to considerably shorter down times but the failure rate is much higher. Severe rotor failures seem to be rare, but they occur and the consequences can be dramatic. Operators and insurance companies are demanding improved insight in damage collection, maintenance and overall damage preventing measures. Closer cooperation with these parties could be a fruitful way of gathering more useful data. Improvements for future databases are suggested. A structure for damage collection is proposed. Comparing experience of damage preventing measures from other industries, knowledge about the nature of the damage mechanism and current practice in the wind industry will be an important tool in the evaluation of different damage preventing measures. This will be done in the following phases of this project

Preliminary Framework for Human-Automation Collaboration

International Nuclear Information System (INIS)

Oxstrand, Johanna Helene; Le Blanc, Katya Lee; Spielman, Zachary Alexander

2015-01-01

The Department of Energy's Advanced Reactor Technologies Program sponsors research, development and deployment activities through its Next Generation Nuclear Plant, Advanced Reactor Concepts, and Advanced Small Modular Reactor (aSMR) Programs to promote safety, technical, economical, and environmental advancements of innovative Generation IV nuclear energy technologies. The Human Automation Collaboration (HAC) Research Project is located under the aSMR Program, which identifies developing advanced instrumentation and controls and human-machine interfaces as one of four key research areas. It is expected that the new nuclear power plant designs will employ technology significantly more advanced than the analog systems in the existing reactor fleet as well as utilizing automation to a greater extent. Moving towards more advanced technology and more automation does not necessary imply more efficient and safer operation of the plant. Instead, a number of concerns about how these technologies will affect human performance and the overall safety of the plant need to be addressed. More specifically, it is important to investigate how the operator and the automation work as a team to ensure effective and safe plant operation, also known as the human-automation collaboration (HAC). The focus of the HAC research is to understand how various characteristics of automation (such as its reliability, processes, and modes) effect an operator's use and awareness of plant conditions. In other words, the research team investigates how to best design the collaboration between the operators and the automated systems in a manner that has the greatest positive impact on overall plant performance and reliability. This report addresses the Department of Energy milestone M4AT-15IN2302054, Complete Preliminary Framework for Human-Automation Collaboration, by discussing the two phased development of a preliminary HAC framework. The framework developed in the first phase was used as

Preliminary Framework for Human-Automation Collaboration

Energy Technology Data Exchange (ETDEWEB)

Oxstrand, Johanna Helene [Idaho National Lab. (INL), Idaho Falls, ID (United States); Le Blanc, Katya Lee [Idaho National Lab. (INL), Idaho Falls, ID (United States); Spielman, Zachary Alexander [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-09-01

The Department of Energy’s Advanced Reactor Technologies Program sponsors research, development and deployment activities through its Next Generation Nuclear Plant, Advanced Reactor Concepts, and Advanced Small Modular Reactor (aSMR) Programs to promote safety, technical, economical, and environmental advancements of innovative Generation IV nuclear energy technologies. The Human Automation Collaboration (HAC) Research Project is located under the aSMR Program, which identifies developing advanced instrumentation and controls and human-machine interfaces as one of four key research areas. It is expected that the new nuclear power plant designs will employ technology significantly more advanced than the analog systems in the existing reactor fleet as well as utilizing automation to a greater extent. Moving towards more advanced technology and more automation does not necessary imply more efficient and safer operation of the plant. Instead, a number of concerns about how these technologies will affect human performance and the overall safety of the plant need to be addressed. More specifically, it is important to investigate how the operator and the automation work as a team to ensure effective and safe plant operation, also known as the human-automation collaboration (HAC). The focus of the HAC research is to understand how various characteristics of automation (such as its reliability, processes, and modes) effect an operator’s use and awareness of plant conditions. In other words, the research team investigates how to best design the collaboration between the operators and the automated systems in a manner that has the greatest positive impact on overall plant performance and reliability. This report addresses the Department of Energy milestone M4AT-15IN2302054, Complete Preliminary Framework for Human-Automation Collaboration, by discussing the two phased development of a preliminary HAC framework. The framework developed in the first phase was used as the

Collaborative Environments. Considerations Concerning Some Collaborative Systems

Directory of Open Access Journals (Sweden)

Mihaela I. MUNTEAN

2009-01-01

Full Text Available It is obvious, that all collaborative environments (workgroups, communities of practice, collaborative enterprises are based on knowledge and between collaboration and knowledge management there is a strong interdependence. The evolution of information systems in these collaborative environments led to the sudden necessity to adopt, for maintaining the virtual activities and processes, the latest technologies/systems, which are capable to support integrated collaboration in business services. In these environments, portal-based IT platforms will integrate multi-agent collaborative systems, collaborative tools, different enterprise applications and other useful information systems.

A Collaborative Reasoning Maintenance System for a Reliable Application of Legislations

Science.gov (United States)

Tamisier, Thomas; Didry, Yoann; Parisot, Olivier; Feltz, Fernand

Decision support systems are nowadays used to disentangle all kinds of intricate situations and perform sophisticated analysis. Moreover, they are applied in areas where the knowledge can be heterogeneous, partially un-formalized, implicit, or diffuse. The representation and management of this knowledge become the key point to ensure the proper functioning of the system and keep an intuitive view upon its expected behavior. This paper presents a generic architecture for implementing knowledge-base systems used in collaborative business, where the knowledge is organized into different databases, according to the usage, persistence and quality of the information. This approach is illustrated with Cadral, a customizable automated tool built on this architecture and used for processing family benefits applications at the National Family Benefits Fund of the Grand-Duchy of Luxembourg.

Grid Compatibility of Variable Speed Wind Turbines with Directly Coupled Synchronous Generator and Hydro-Dynamically Controlled Gearbox

Energy Technology Data Exchange (ETDEWEB)

Mueller, H.; Poeller, M. [DIgSILENT GmbH, 72810 Gomaringen (Germany); Basteck, A.; Tilscher, M.; Pfister, J. [Voith Turbo GmbH and Co. KG, 74564 Crailsheim (Germany)

2006-07-01

This paper analyzes grid integration aspects of a new type of variable-speed wind turbine, the directly coupled synchronous generator with hydro-dynamically controlled gearbox. In contrast to existing wind generators using synchronous generators, the generator of this concept is directly connected to the AC grid, without the application of any power electronics converter. Variable speed operation of the turbine is mechanically achieved by a gear box with continuously controllable variable gear box ratio. For this purpose, a detailed dynamic model of a 2 MW wind turbine with a Voith WinDrive has been implemented using the modelling environment of the simulation software DIgSILENT PowerFactory. For investigating grid compatibility aspects of this new wind generator concept, a model of a 50 MW wind farm, with typical layout, based on 25 wind turbines of the 2 MW-class has been analyzed. This paper focuses on the compatibility of the new concept with existing connection standards, such as the E.ON grid code. Of special interest are typical stability phenomena of synchronous generators, such as transient and oscillatory stability as well as power quality issues like voltage flicker. The results of stability studies are presented and possible advantages of the new concept with special focus on offshore applications are discussed.

Collaborative Engineering for Research and Development

Science.gov (United States)

Davis, Jose M.; Keys, L. Ken; Chen, Injazz J.

2004-01-01

Research and development (R&D) organizations are being required to be relevant, to be more application-oriented, and to be partners in the strategic management of the business while meeting the same challenges as the rest of the organization, namely: (1) reduced time to market; (2) reduced cost; (3) improved quality; (4) increased reliability; and (5) increased focus on customer needs. Recent advances in computer technology and the Internet have created a new paradigm of collaborative engineering or collaborative product development (CPD), from which new types of relationships among researchers and their partners have emerged. Research into the applicability and benefits of CPD in a low/no production, R&D, and/or government environment is limited. In addition, the supply chain management (SCM) aspects of these relationships have not been studied. This paper presents research conducted at the NASA Glenn Research Center (GRC) investigating the applicability of CPD and SCM in an R&D organization. The study concentrates on the management and implementation of space research activities at GRC. Results indicate that although the organization is engaged in collaborative relationships that incorporate aspects of SCM, a number of areas, such as development of trust and information sharing merit special attention.

Reliability Engineering Analysis of ATLAS Data Reprocessing Campaigns

CERN Document Server

Vaniachine, A; The ATLAS collaboration; Karpenko, D

2013-01-01

During three years of LHC data taking, the ATLAS collaboration completed three petascale data reprocessing campaigns on the Grid, with up to 2 PB of data being reprocessed every year. In reprocessing on the Grid, failures can occur for a variety of reasons, while Grid heterogeneity makes failures hard to diagnose and repair quickly. As a result, Big Data processing on the Grid must tolerate a continuous stream of failures, errors and faults. While ATLAS fault-tolerance mechanisms improve the reliability of Big Data processing in the Grid, their benefits come at costs and result in delays making the performance prediction difficult. Reliability Engineering provides a framework for fundamental understanding of the Big Data processing on the Grid, which is not a desirable enhancement but a necessary requirement. In ATLAS, cost monitoring and performance prediction became critical for the success of the reprocessing campaigns conducted in preparation for the major physics conferences. In addition, our Reliability...

Reliability Engineering Analysis of ATLAS Data Reprocessing Campaigns

CERN Document Server

Vaniachine, A; The ATLAS collaboration; Karpenko, D

2014-01-01

During three years of LHC data taking, the ATLAS collaboration completed three petascale data reprocessing campaigns on the Grid, with up to 2 PB of data being reprocessed every year. In reprocessing on the Grid, failures can occur for a variety of reasons, while Grid heterogeneity makes failures hard to diagnose and repair quickly. As a result, Big Data processing on the Grid must tolerate a continuous stream of failures, errors and faults. While ATLAS fault-tolerance mechanisms improve the reliability of Big Data processing in the Grid, their benefits come at costs and result in delays making the performance prediction difficult. Reliability Engineering provides a framework for fundamental understanding of the Big Data processing on the Grid, which is not a desirable enhancement but a necessary requirement. In ATLAS, cost monitoring and performance prediction became critical for the success of the reprocessing campaigns conducted in preparation for the major physics conferences. In addition, our Reliability...

Reliability-Centric Analysis of Offloaded Computation in Cooperative Wearable Applications

Directory of Open Access Journals (Sweden)

Aleksandr Ometov

2017-01-01

Full Text Available Motivated by the unprecedented penetration of mobile communications technology, this work carefully brings into perspective the challenges related to heterogeneous communications and offloaded computation operating in cases of fault-tolerant computation, computing, and caching. We specifically focus on the emerging augmented reality applications that require reliable delegation of the computing and caching functionality to proximate resource-rich devices. The corresponding mathematical model proposed in this work becomes of value to assess system-level reliability in cases where one or more nearby collaborating nodes become temporarily unavailable. Our produced analytical and simulation results corroborate the asymptotic insensitivity of the stationary reliability of the system in question (under the “fast” recovery of its elements to the type of the “repair” time distribution, thus supporting the fault-tolerant system operation.

NDT Reliability - Final Report. Reliability in non-destructive testing (NDT) of the canister components

Energy Technology Data Exchange (ETDEWEB)

Pavlovic, Mato; Takahashi, Kazunori; Mueller, Christina; Boehm, Rainer (BAM, Federal Inst. for Materials Research and Testing, Berlin (Germany)); Ronneteg, Ulf (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden))

2008-12-15

This report describes the methodology of the reliability investigation performed on the ultrasonic phased array NDT system, developed by SKB in collaboration with Posiva, for inspection of the canisters for permanent storage of nuclear spent fuel. The canister is composed of a cast iron insert surrounded by a copper shell. The shell is composed of the tube and the lid/base which are welded to the tube after the fuel has been place, in the tube. The manufacturing process of the canister parts and the welding process are described. Possible defects, which might arise in the canister components during the manufacturing or in the weld during the welding, are identified. The number of real defects in manufactured components have been limited. Therefore the reliability of the NDT system has been determined using a number of test objects with artificial defects. The reliability analysis is based on the signal response analysis. The conventional signal response analysis is adopted and further developed before applied on the modern ultrasonic phased-array NDT system. The concept of multi-parameter a, where the response of the NDT system is dependent on more than just one parameter, is introduced. The weakness of use of the peak signal response in the analysis is demonstrated and integration of the amplitudes in the C-scan is proposed as an alternative. The calculation of the volume POD, when the part is inspected with more configurations, is also presented. The reliability analysis is supported by the ultrasonic simulation based on the point source synthesis method

Adopting Continuous Delivery and Deployment: Impacts on Team Structures, Collaboration and Responsibilities

DEFF Research Database (Denmark)

Shahin, Mojtaba; Zahedi, Mansooreh; Babar, Muhammad Ali

2017-01-01

Context: Continuous Delivery and Deployment (CD) practices aim to deliver software features more frequently and reliably. While some efforts have been made to study different aspects of CD practices, a little empirical work has been reported on the impact of CD on team structures, collaboration a...

A framework using cluster-based hybrid network architecture for collaborative virtual surgery.

Science.gov (United States)

Qin, Jing; Choi, Kup-Sze; Poon, Wai-Sang; Heng, Pheng-Ann

2009-12-01

Research on collaborative virtual environments (CVEs) opens the opportunity for simulating the cooperative work in surgical operations. It is however a challenging task to implement a high performance collaborative surgical simulation system because of the difficulty in maintaining state consistency with minimum network latencies, especially when sophisticated deformable models and haptics are involved. In this paper, an integrated framework using cluster-based hybrid network architecture is proposed to support collaborative virtual surgery. Multicast transmission is employed to transmit updated information among participants in order to reduce network latencies, while system consistency is maintained by an administrative server. Reliable multicast is implemented using distributed message acknowledgment based on cluster cooperation and sliding window technique. The robustness of the framework is guaranteed by the failure detection chain which enables smooth transition when participants join and leave the collaboration, including normal and involuntary leaving. Communication overhead is further reduced by implementing a number of management approaches such as computational policies and collaborative mechanisms. The feasibility of the proposed framework is demonstrated by successfully extending an existing standalone orthopedic surgery trainer into a collaborative simulation system. A series of experiments have been conducted to evaluate the system performance. The results demonstrate that the proposed framework is capable of supporting collaborative surgical simulation.

The role of cultural intelligence of managers in promoting employees’ collaboration

Directory of Open Access Journals (Sweden)

Seyed Ali Akbar Ahmadi

2013-07-01

Full Text Available Collaboration can be a very challenging process precisely because it is a highly intense way of working, requiring new ways of thinking, behavior and ways of operating. Cultural Intelligence (CI is an antecedent for collaboration . The primary goal of this survey is to investigate the relationship between cultural intelligence of managers and their employees’ collaboration. This research is a descriptive-correlation study where 119 managers and 175 employees are selected by stratified random sampling from the Social Security organization managers and their workers. To measure cultural intelligence, the Iranian version of the cultural intelligence questionnaire is implemented and collaboration is measured using a questionnaire developed by the researcher. The Cronbach's alpha reliability coefficient respectively for cultural intelligence and collaboration questionnaires are 0.933 and 0.813, respectively, which are well above the minimum acceptable limit. Data collected using SPSS 19 and they are analyzed using LISREL 8.54 software packages. The results indicate a significant and positive relationship between cultural intelligence among managers and their employees’ collaboration. As the relationship between motivational and behavioral CI dimensions and collaboration is also determined to be positive and significant. Based on demographic factors such as gender, age and education we cannot comment on the cultural intelligence of managers and employee’s collaboration but having inter-cultural experiences has had a positive impact on the cultural intelligence of managers. Based on the findings obtained we can say that Cultural Intelligence is a key factor, influencing and determining for collaboration.

Distributed collaborative probabilistic design of multi-failure structure with fluid-structure interaction using fuzzy neural network of regression

Science.gov (United States)

Song, Lu-Kai; Wen, Jie; Fei, Cheng-Wei; Bai, Guang-Chen

2018-05-01

To improve the computing efficiency and precision of probabilistic design for multi-failure structure, a distributed collaborative probabilistic design method-based fuzzy neural network of regression (FR) (called as DCFRM) is proposed with the integration of distributed collaborative response surface method and fuzzy neural network regression model. The mathematical model of DCFRM is established and the probabilistic design idea with DCFRM is introduced. The probabilistic analysis of turbine blisk involving multi-failure modes (deformation failure, stress failure and strain failure) was investigated by considering fluid-structure interaction with the proposed method. The distribution characteristics, reliability degree, and sensitivity degree of each failure mode and overall failure mode on turbine blisk are obtained, which provides a useful reference for improving the performance and reliability of aeroengine. Through the comparison of methods shows that the DCFRM reshapes the probability of probabilistic analysis for multi-failure structure and improves the computing efficiency while keeping acceptable computational precision. Moreover, the proposed method offers a useful insight for reliability-based design optimization of multi-failure structure and thereby also enriches the theory and method of mechanical reliability design.

Advanced wireless mobile collaborative sensing network for tactical and strategic missions

Science.gov (United States)

Xu, Hao

2017-05-01

In this paper, an advanced wireless mobile collaborative sensing network will be developed. Through properly combining wireless sensor network, emerging mobile robots and multi-antenna sensing/communication techniques, we could demonstrate superiority of developed sensing network. To be concrete, heterogeneous mobile robots including unmanned aerial vehicle (UAV) and unmanned ground vehicle (UGV) are equipped with multi-model sensors and wireless transceiver antennas. Through real-time collaborative formation control, multiple mobile robots can team the best formation that can provide most accurate sensing results. Also, formatting multiple mobile robots can also construct a multiple-input multiple-output (MIMO) communication system that can provide a reliable and high performance communication network.

Collaborative Economy

DEFF Research Database (Denmark)

collaborative economy and tourism Dianne Dredge and Szilvia Gyimóthy PART I - Theoretical explorations 2.Definitions and mapping the landscape in the collaborative economy Szilvia Gyimóthy and Dianne Dredge 3.Business models of the collaborative economy Szilvia Gyimóthy 4.Responsibility and care...... in the collaborative economy Dianne Dredge 5.Networked cultures in the collaborative economy Szilvia Gyimóthy 6.Policy and regulatory perspectives in the collaborative economy Dianne Dredge PART II - Disruptions, innovations and transformations 7.Regulating innovation in the collaborative economy: An examination...... localities of tourism Greg Richards 11.Collaborative economy and destination marketing organizations: A systems approach Jonathan Day 12.Working within the Collaborative Tourist Economy: The complex crafting of work and meaning Jane Widtfeldt Meged and Mathilde Dissing Christensen PART - III Encounters...

Factors influencing teamwork and collaboration within a tertiary medical center.

Science.gov (United States)

Chien, Shu Feng; Wan, Thomas Th; Chen, Yu-Chih

2012-04-26

To understand how work climate and related factors influence teamwork and collaboration in a large medical center. A survey of 3462 employees was conducted to generate responses to Sexton's Safety Attitudes Questionnaire (SAQ) to assess perceptions of work environment via a series of five-point, Likert-scaled questions. Path analysis was performed, using teamwork (TW) and collaboration (CO) as endogenous variables. The exogenous variables are effective communication (EC), safety culture (SC), job satisfaction (JS), work pressure (PR), and work climate (WC). The measurement instruments for the variables or summated subscales are presented. Reliability of each sub-scale are calculated. Alpha Cronbach coefficients are relatively strong: TW (0.81), CO (0.76), EC (0.70), SC (0.83), JS (0.91), WP (0.85), and WC (0.78). Confirmatory factor analysis was performed for each of these constructs. Path analysis enables to identify statistically significant predictors of two endogenous variables, teamwork and intra-organizational collaboration. Significant amounts of variance in perceived teamwork (R(2) = 0.59) and in collaboration (R(2) = 0.75) are accounted for by the predictor variables. In the initial model, safety culture is the most important predictor of perceived teamwork, with a β weight of 0.51, and work climate is the most significant predictor of collaboration, with a β weight of 0.84. After eliminating statistically insignificant causal paths and allowing correlated predictors1, the revised model shows that work climate is the only predictor positively influencing both teamwork (β = 0.26) and collaboration (β = 0.88). A relatively weak positive (β = 0.14) but statistically significant relationship exists between teamwork and collaboration when the effects of other predictors are simultaneously controlled. Hospital executives who are interested in improving collaboration should assess the work climate to ensure that employees are operating in a setting conducive

Factors influencing teamwork and collaboration within a tertiary medical center

Science.gov (United States)

Chien, Shu Feng; Wan, Thomas TH; Chen, Yu-Chih

2012-01-01

AIM: To understand how work climate and related factors influence teamwork and collaboration in a large medical center. METHODS: A survey of 3462 employees was conducted to generate responses to Sexton’s Safety Attitudes Questionnaire (SAQ) to assess perceptions of work environment via a series of five-point, Likert-scaled questions. Path analysis was performed, using teamwork (TW) and collaboration (CO) as endogenous variables. The exogenous variables are effective communication (EC), safety culture (SC), job satisfaction (JS), work pressure (PR), and work climate (WC). The measurement instruments for the variables or summated subscales are presented. Reliability of each sub-scale are calculated. Alpha Cronbach coefficients are relatively strong: TW (0.81), CO (0.76), EC (0.70), SC (0.83), JS (0.91), WP (0.85), and WC (0.78). Confirmatory factor analysis was performed for each of these constructs. RESULTS: Path analysis enables to identify statistically significant predictors of two endogenous variables, teamwork and intra-organizational collaboration. Significant amounts of variance in perceived teamwork (R2 = 0.59) and in collaboration (R2 = 0.75) are accounted for by the predictor variables. In the initial model, safety culture is the most important predictor of perceived teamwork, with a β weight of 0.51, and work climate is the most significant predictor of collaboration, with a β weight of 0.84. After eliminating statistically insignificant causal paths and allowing correlated predictors1, the revised model shows that work climate is the only predictor positively influencing both teamwork (β = 0.26) and collaboration (β = 0.88). A relatively weak positive (β = 0.14) but statistically significant relationship exists between teamwork and collaboration when the effects of other predictors are simultaneously controlled. CONCLUSION: Hospital executives who are interested in improving collaboration should assess the work climate to ensure that employees are

Distributed collaborative probabilistic design for turbine blade-tip radial running clearance using support vector machine of regression

Science.gov (United States)

Fei, Cheng-Wei; Bai, Guang-Chen

2014-12-01

To improve the computational precision and efficiency of probabilistic design for mechanical dynamic assembly like the blade-tip radial running clearance (BTRRC) of gas turbine, a distribution collaborative probabilistic design method-based support vector machine of regression (SR)(called as DCSRM) is proposed by integrating distribution collaborative response surface method and support vector machine regression model. The mathematical model of DCSRM is established and the probabilistic design idea of DCSRM is introduced. The dynamic assembly probabilistic design of aeroengine high-pressure turbine (HPT) BTRRC is accomplished to verify the proposed DCSRM. The analysis results reveal that the optimal static blade-tip clearance of HPT is gained for designing BTRRC, and improving the performance and reliability of aeroengine. The comparison of methods shows that the DCSRM has high computational accuracy and high computational efficiency in BTRRC probabilistic analysis. The present research offers an effective way for the reliability design of mechanical dynamic assembly and enriches mechanical reliability theory and method.

Improved Targeting Through Collaborative Decision-Making and Brain Computer Interfaces

Science.gov (United States)

Stoica, Adrian; Barrero, David F.; McDonald-Maier, Klaus

2013-01-01

This paper reports a first step toward a brain-computer interface (BCI) for collaborative targeting. Specifically, we explore, from a broad perspective, how the collaboration of a group of people can increase the performance on a simple target identification task. To this end, we requested a group of people to identify the location and color of a sequence of targets appearing on the screen and measured the time and accuracy of the response. The individual results are compared to a collective identification result determined by simple majority voting, with random choice in case of drawn. The results are promising, as the identification becomes significantly more reliable even with this simple voting and a small number of people (either odd or even number) involved in the decision. In addition, the paper briefly analyzes the role of brain-computer interfaces in collaborative targeting, extending the targeting task by using a BCI instead of a mechanical response.

A New Acoustic Emission Sensor Based Gear Fault Detection Approach

Directory of Open Access Journals (Sweden)

Junda Zhu

2013-01-01

Full Text Available In order to reduce wind energy costs, prognostics and health management (PHM of wind turbine is needed to ensure the reliability and availability of wind turbines. A gearbox is an important component of a wind turbine. Therefore, developing effective gearbox fault detection tools is important to the PHM of wind turbine. In this paper, a new acoustic emission (AE sensor based gear fault detection approach is presented. This approach combines a heterodyne based frequency reduction technique with time synchronous average (TSA and spectrum kurtosis (SK to process AE sensor signals and extract features as condition indictors for gear fault detection. Heterodyne technique commonly used in communication is first employed to preprocess the AE signals before sampling. By heterodyning, the AE signal frequency is down shifted from several hundred kHz to below 50 kHz. This reduced AE signal sampling rate is comparable to that of vibration signals. The presented approach is validated using seeded gear tooth crack fault tests on a notational split torque gearbox. The approach presented in this paper is physics based and the validation results have showed that it could effectively detect the gear faults.

Reliability and maintainability data acquisition in equipment development tests

International Nuclear Information System (INIS)

Haire, M.J.; Gift, E.H.

1983-10-01

The need for collection of reliability, maintainability, and availability data adds a new dimension to the data acquisition requirements of equipment development tests. This report describes the reliability and maintainability data that are considered necessary to ensure that sufficient and high quality data exist for a comprehensive, quantitative evaluation of equipment and system availability. These necessary data are presented as a set of data collection forms. Three data acquisition forms are discussed: an inventory and technical data form, which is filed by the design engineer when the design is finished or the equipment is received; an event report form, which is completed by the senior test operator at each shutdown; and a maintainability report, which is a collaborative effort between senior operators and lead engineers and is completed on restart. In addition, elements of a reliability, maintainability evaluation program are described. Emphasis is placed on the role of data, its storage, and use in such a program

Collaboration

Science.gov (United States)

King, Michelle L.

2010-01-01

This article explores collaboration between library media educators and regular classroom teachers. The article focuses on the context of the issue, positions on the issue, the impact of collaboration, and how to implement effective collaboration into the school system. Various books and professional journals are used to support conclusions…

Framework for Risk-based Planning of Operation and Maintenance for Offshore Wind Turbines

DEFF Research Database (Denmark)

Sørensen, John Dalsgaard

2009-01-01

, and to sequential optimal decision making on planning of OM taking into account new information. Deterioration mechanisms such as fatigue, corrosion, wear and erosion are associated with significant uncertainty. Observations of the degree of damage can increase the reliability of predictions, especially......For offshore wind turbines, costs to operation and maintenance (OM) are substantial. This paper describes a risk-based life cycle approach for optimal planning of OM. The approach is based on pre-posterior Bayesian decision theory, and can be used both to overall, initial planning of OM...... in connection with condition-based maintenance. The approach can be used for gearboxes, generators, fatigue cracks, corrosion, etc. This paper also describes how probabilistic indicators can be used to quantify indirect information about the damage state for critical components, e.g. gearboxes....

Collaboration 'Engineerability'

NARCIS (Netherlands)

Kolfschoten, Gwendolyn L.; de Vreede, Gert-Jan; Briggs, Robert O.; Sol, Henk G.

Collaboration Engineering is an approach to create sustained collaboration support by designing collaborative work practices for high-value recurring tasks, and transferring those designs to practitioners to execute for themselves without ongoing support from collaboration professionals. A key

Collaborative Economy

DEFF Research Database (Denmark)

that are emerging from them, and how governments are responding to these new challenges. In doing so, the book provides both theoretical and practical insights into the future of tourism in a world that is, paradoxically, becoming both increasingly collaborative and individualized. Table of Contents Preface 1.The...... collaborative economy and tourism Dianne Dredge and Szilvia Gyimóthy PART I - Theoretical explorations 2.Definitions and mapping the landscape in the collaborative economy Szilvia Gyimóthy and Dianne Dredge 3.Business models of the collaborative economy Szilvia Gyimóthy 4.Responsibility and care...... in the collaborative economy Dianne Dredge 5.Networked cultures in the collaborative economy Szilvia Gyimóthy 6.Policy and regulatory perspectives in the collaborative economy Dianne Dredge PART II - Disruptions, innovations and transformations 7.Regulating innovation in the collaborative economy: An examination...

Reliability engineering analysis of ATLAS data reprocessing campaigns

International Nuclear Information System (INIS)

Vaniachine, A; Golubkov, D; Karpenko, D

2014-01-01

During three years of LHC data taking, the ATLAS collaboration completed three petascale data reprocessing campaigns on the Grid, with up to 2 PB of data being reprocessed every year. In reprocessing on the Grid, failures can occur for a variety of reasons, while Grid heterogeneity makes failures hard to diagnose and repair quickly. As a result, Big Data processing on the Grid must tolerate a continuous stream of failures, errors and faults. While ATLAS fault-tolerance mechanisms improve the reliability of Big Data processing in the Grid, their benefits come at costs and result in delays making the performance prediction difficult. Reliability Engineering provides a framework for fundamental understanding of the Big Data processing on the Grid, which is not a desirable enhancement but a necessary requirement. In ATLAS, cost monitoring and performance prediction became critical for the success of the reprocessing campaigns conducted in preparation for the major physics conferences. In addition, our Reliability Engineering approach supported continuous improvements in data reprocessing throughput during LHC data taking. The throughput doubled in 2011 vs. 2010 reprocessing, then quadrupled in 2012 vs. 2011 reprocessing. We present the Reliability Engineering analysis of ATLAS data reprocessing campaigns providing the foundation needed to scale up the Big Data processing technologies beyond the petascale.

Explaining interindividual differences in toddlers’ collaboration with unfamiliar peers: Individual, dyadic, and social factors

Directory of Open Access Journals (Sweden)

Nils eSchuhmacher

2015-05-01

Full Text Available During their third year of life, toddlers become increasingly skillful at coordinating their actions with peer partners and they form joint commitments in collaborative situations. However, little effort has been made to explain interindividual differences in collaboration among toddlers. Therefore, we examined the relative influence of distinct individual, dyadic, and social factors on toddlers’ collaborative activities (i.e., level of coordination and preference for joint activity in joint problem-solving situations with unfamiliar peer partners (n = 23 dyads aged M = 35.7 months. We analyzed the dyadic nonindependent data with mixed models. Results indicated that mothers’ expectations regarding their children’s social behaviors significantly predicted toddlers’ level of coordination. Furthermore, the models revealed that toddlers’ positive mutual experiences with the unfamiliar partner assessed during an initial free play period (Phase 1 and their level of coordination in an obligatory collaboration task (Phase 2 promoted toddlers’ preference for joint activity in a subsequent optional collaboration task (Phase 3. In contrast, children’s mastery motivation and shyness conflicted with their collaborative efforts. We discuss the role of parents’ socialization goals in toddlers’ development toward becoming active collaborators and discuss possible mechanisms underlying the differences in toddlers’ commitment to joint activities, namely social preferences and the trust in reliable cooperation partners.

Collaborative Economy

DEFF Research Database (Denmark)

collaborative economy and tourism Dianne Dredge and Szilvia Gyimóthy PART I - Theoretical explorations 2.Definitions and mapping the landscape in the collaborative economy Szilvia Gyimóthy and Dianne Dredge 3.Business models of the collaborative economy Szilvia Gyimóthy 4.Responsibility and care...... and similar phenomena are among these collective innovations in tourism that are shaking the very bedrock of an industrial system that has been traditionally sustained along commercial value chains. To date there has been very little investigation of these trends, which have been inspired by, amongst other...... in the collaborative economy Dianne Dredge 5.Networked cultures in the collaborative economy Szilvia Gyimóthy 6.Policy and regulatory perspectives in the collaborative economy Dianne Dredge PART II - Disruptions, innovations and transformations 7.Regulating innovation in the collaborative economy: An examination...

Collaborative information seeking

DEFF Research Database (Denmark)

Hertzum, Morten

2008-01-01

Since common ground is pivotal to collaboration, this paper proposes to define collaborative information seeking as the combined activity of information seeking and collaborative grounding. While information-seeking activities are necessary for collaborating actors to acquire new information......, the activities involved in information seeking are often performed by varying subgroups of actors. Consequently, collaborative grounding is necessary to share information among collaborating actors and, thereby, establish and maintain the common ground necessary for their collaborative work. By focusing...... on the collaborative level, collaborative information seeking aims to avoid both individual reductionism and group reductionism, while at the same time recognizing that only some information and understanding need be shared....

UNEDF: Advanced Scientific Computing Collaboration Transforms the Low-Energy Nuclear Many-Body Problem

International Nuclear Information System (INIS)

Nam, H; Stoitsov, M; Nazarewicz, W; Hagen, G; Kortelainen, M; Pei, J C; Bulgac, A; Maris, P; Vary, J P; Roche, K J; Schunck, N; Thompson, I; Wild, S M

2012-01-01

The demands of cutting-edge science are driving the need for larger and faster computing resources. With the rapidly growing scale of computing systems and the prospect of technologically disruptive architectures to meet these needs, scientists face the challenge of effectively using complex computational resources to advance scientific discovery. Multi-disciplinary collaborating networks of researchers with diverse scientific backgrounds are needed to address these complex challenges. The UNEDF SciDAC collaboration of nuclear theorists, applied mathematicians, and computer scientists is developing a comprehensive description of nuclei and their reactions that delivers maximum predictive power with quantified uncertainties. This paper describes UNEDF and identifies attributes that classify it as a successful computational collaboration. We illustrate significant milestones accomplished by UNEDF through integrative solutions using the most reliable theoretical approaches, most advanced algorithms, and leadership-class computational resources.

Advanced Reactor PSA Methodologies for System Reliability Analysis and Source Term Assessment

Energy Technology Data Exchange (ETDEWEB)

Grabaskas, D.; Brunett, A.; Passerini, S.; Grelle, A.; Bucknor, M.

2017-06-26

Beginning in 2015, a project was initiated to update and modernize the probabilistic safety assessment (PSA) of the GE-Hitachi PRISM sodium fast reactor. This project is a collaboration between GE-Hitachi and Argonne National Laboratory (Argonne), and funded in part by the U.S. Department of Energy. Specifically, the role of Argonne is to assess the reliability of passive safety systems, complete a mechanistic source term calculation, and provide component reliability estimates. The assessment of passive system reliability focused on the performance of the Reactor Vessel Auxiliary Cooling System (RVACS) and the inherent reactivity feedback mechanisms of the metal fuel core. The mechanistic source term assessment attempted to provide a sequence specific source term evaluation to quantify offsite consequences. Lastly, the reliability assessment focused on components specific to the sodium fast reactor, including electromagnetic pumps, intermediate heat exchangers, the steam generator, and sodium valves and piping.

Evaluation of the reliability of a passive system

International Nuclear Information System (INIS)

Bianchi, F.; Burgazzi, L.; D'Auria, F.; Galassi, G.M.; Ricotti, M.E.; Oriani, L.

2001-01-01

A passive system should be theoretically more reliable than an active one. In fact its operation is independent by any external input or energy and is relied only upon natural physical laws (e.g., gravity, natural circulation, etc.) and/or 'intelligent' use of the energy inherently available in the system (e.g., chemical reaction, decay heat, etc.). Nevertheless the passive system may fail its mission as consequences of component failures, deviation of physical phenomena, boundary and/or initial conditions from the expectation. This document describes at first the methodology developed by ENEA, in collaboration of University of Pisa and Polytechnic of Milano, allowing the evaluation of the reliability for a passive system, which operation is based on moving working fluids (type B and C, cf. IAEA). It reports the results of an exercise performed on a system, which operation is based on Natural Circulation.(author)

Collaborative Product Development in an R&D Environment

Science.gov (United States)

Davis, Jose M.; Keys, L. Ken; Chen, Injazz J.; Peterson, Paul L.

2004-01-01

Research and development (R&D) organizations are being required to be relevant, to be more application-oriented, and to be partners in the strategic management of the business while meeting the same challenges as the rest of the organization, namely: (1) reduced time to market; (2) reduced cost; (3) improved quality; (4) increased reliability; and (5) increased focus on customer needs. Recent advances in computer technology and the Internet have created a new paradigm of collaborative engineering or collaborative product development (CPD), from which new types of relationships among researchers and their partners have emerged. Research into the applicability and benefits of CPD in a low/no production, R&D, and/or government environment is limited. In addition, the supply chain management (SCM) aspects of these relationships have not been studied. This paper presents research conducted at the NASA Glenn Research Center (GRC) investigating the applicability of CPD and SCM in an R&D organization. The study concentrates on the management and implementation of space research activities at GRC. Results indicate that although the organization is engaged in collaborative relationships that incorporate aspects of SCM, a number of areas, such as development of trust and information sharing merit special attention.

E-Services quality assessment framework for collaborative networks

Science.gov (United States)

Stegaru, Georgiana; Danila, Cristian; Sacala, Ioan Stefan; Moisescu, Mihnea; Mihai Stanescu, Aurelian

2015-08-01

In a globalised networked economy, collaborative networks (CNs) are formed to take advantage of new business opportunities. Collaboration involves shared resources and capabilities, such as e-Services that can be dynamically composed to automate CN participants' business processes. Quality is essential for the success of business process automation. Current approaches mostly focus on quality of service (QoS)-based service selection and ranking algorithms, overlooking the process of service composition which requires interoperable, adaptable and secure e-Services to ensure seamless collaboration, data confidentiality and integrity. Lack of assessment of these quality attributes can result in e-Service composition failure. The quality of e-Service composition relies on the quality of each e-Service and on the quality of the composition process. Therefore, there is the need for a framework that addresses quality from both views: product and process. We propose a quality of e-Service composition (QoESC) framework for quality assessment of e-Service composition for CNs which comprises of a quality model for e-Service evaluation and guidelines for quality of e-Service composition process. We implemented a prototype considering a simplified telemedicine use case which involves a CN in e-Healthcare domain. To validate the proposed quality-driven framework, we analysed service composition reliability with and without using the proposed framework.

Mechatronic modeling of a 750kW fixed-speed wind energy conversion system using the Bond Graph Approach.

Science.gov (United States)

Khaouch, Zakaria; Zekraoui, Mustapha; Bengourram, Jamaa; Kouider, Nourreeddine; Mabrouki, Mustapha

2016-11-01

In this paper, we would like to focus on modeling main parts of the wind turbines (blades, gearbox, tower, generator and pitching system) from a mechatronics viewpoint using the Bond-Graph Approach (BGA). Then, these parts are combined together in order to simulate the complete system. Moreover, the real dynamic behavior of the wind turbine is taken into account and with the new model; final load simulation is more realistic offering benefits and reliable system performance. This model can be used to develop control algorithms to reduce fatigue loads and enhance power production. Different simulations are carried-out in order to validate the proposed wind turbine model, using real data provided in the open literature (blade profile and gearbox parameters for a 750 kW wind turbine). Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Collaborative experience

DEFF Research Database (Denmark)

Mortensen, Thomas Bøtker

-Doerr, 1996) and has been shown to have a positive effect to the outcome of collaborative R&D (Sampson, 2005). Anand & Khanna (2000), furthermore, hypothesized that research joint ventures are more ambiguous than marketing joint ventures and even more the licensing and showed that the effect of collaborative......Literature review: Collaborative experience has been shown to have a positive effect on the collaborative outcome in general (Anand & Khanna, 2000; Kale, Dyer & Singh, 2002). Furthermore, it has been linked to the ability to exploit the network of the firm for learning (Powell, Koput and Smith...... experience was largest the higher the hypothesized ambiguity. Theoretically contribution: This research project aims at contributing to existing literature by arguing, that collaborative experience is a moderating variable which moderates the effects on collaborative outcome from the level of complexity...

An analysis on intersectional collaboration on non-communicable chronic disease prevention and control in China: a cross-sectional survey on main officials of community health service institutions.

Science.gov (United States)

Li, Xing-Ming; Rasooly, Alon; Peng, Bo; JianWang; Xiong, Shu-Yu

2017-11-10

Our study aimed to design a tool of evaluating intersectional collaboration on Non-communicable Chronic Disease (NCD) prevention and control, and further to understand the current status of intersectional collaboration in community health service institutions of China. We surveyed 444 main officials of community health service institutions in Beijing, Tianjin, Hubei and Ningxia regions of China in 2014 by using a questionnaire. A model of collaboration measurement, including four relational dimensions of governance, shared goals and vision, formalization and internalization, was used to compare the scores of evaluation scale in NCD management procedures across community healthcare institutions and other ones. Reliability and validity of the evaluation tool on inter-organizational collaboration on NCD prevention and control were verified. The test on tool evaluating inter-organizational collaboration in community NCD management revealed a good reliability and validity (Cronbach's Alpha = 0.89,split-half reliability = 0.84, the variance contribution rate of an extracted principal component = 49.70%). The results of inter-organizational collaboration of different departments and management segments showed there were statistically significant differences in formalization dimension for physical examination (p = 0.01).There was statistically significant difference in governance dimension, formalization dimension and total score of the collaboration scale for health record sector (p = 0.01,0.00,0.00). Statistical differences were found in the formalization dimension for exercise and nutrition health education segment (p = 0.01). There were no statistically significant difference in formalization dimension of medication guidance for psychological consultation, medical referral service and rehabilitation guidance (all p > 0.05). The multi-department collaboration mechanism of NCD prevention and control has been rudimentarily established. Community management

Reliable multicast for the Grid: a case study in experimental computer science.

Science.gov (United States)

Nekovee, Maziar; Barcellos, Marinho P; Daw, Michael

2005-08-15

In its simplest form, multicast communication is the process of sending data packets from a source to multiple destinations in the same logical multicast group. IP multicast allows the efficient transport of data through wide-area networks, and its potentially great value for the Grid has been highlighted recently by a number of research groups. In this paper, we focus on the use of IP multicast in Grid applications, which require high-throughput reliable multicast. These include Grid-enabled computational steering and collaborative visualization applications, and wide-area distributed computing. We describe the results of our extensive evaluation studies of state-of-the-art reliable-multicast protocols, which were performed on the UK's high-speed academic networks. Based on these studies, we examine the ability of current reliable multicast technology to meet the Grid's requirements and discuss future directions.

CMS Collaboration

International Nuclear Information System (INIS)

Faridah Mohammad Idris; Wan Ahmad Tajuddin Wan Abdullah; Zainol Abidin Ibrahim

2013-01-01

Full-text: CMS Collaboration is an international scientific collaboration located at European Organization for Nuclear Research (CERN), Switzerland, dedicated in carried out research on experimental particle physics. Consisting of 179 institutions from 41 countries from all around the word, CMS Collaboration host a general purpose detector for example the Compact Muon Solenoid (CMS) for members in CMS Collaboration to conduct experiment from the collision of two proton beams accelerated to a speed of 8 TeV in the LHC ring. In this paper, we described how the CMS detector is used by the scientist in CMS Collaboration to reconstruct the most basic building of matter. (author)

Midwives' and health visitors' collaborative relationships: A systematic review of qualitative and quantitative studies.

Science.gov (United States)

Aquino, Maria Raisa Jessica Ryc V; Olander, Ellinor K; Needle, Justin J; Bryar, Rosamund M

2016-10-01

poor understanding of each other's role. Structural barriers such as physical distance also featured as a challenge to interprofessional collaboration. Although the findings are limited by variable methodological quality, these were consistent across time, geographical locations, and health settings, indicating transferability and reliability. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

An automated method for estimating reliability of grid systems using Bayesian networks

International Nuclear Information System (INIS)

Doguc, Ozge; Emmanuel Ramirez-Marquez, Jose

2012-01-01

Grid computing has become relevant due to its applications to large-scale resource sharing, wide-area information transfer, and multi-institutional collaborating. In general, in grid computing a service requests the use of a set of resources, available in a grid, to complete certain tasks. Although analysis tools and techniques for these types of systems have been studied, grid reliability analysis is generally computation-intensive to obtain due to the complexity of the system. Moreover, conventional reliability models have some common assumptions that cannot be applied to the grid systems. Therefore, new analytical methods are needed for effective and accurate assessment of grid reliability. This study presents a new method for estimating grid service reliability, which does not require prior knowledge about the grid system structure unlike the previous studies. Moreover, the proposed method does not rely on any assumptions about the link and node failure rates. This approach is based on a data-mining algorithm, the K2, to discover the grid system structure from raw historical system data, that allows to find minimum resource spanning trees (MRST) within the grid then, uses Bayesian networks (BN) to model the MRST and estimate grid service reliability.

A collaborative scheduling model for the supply-hub with multiple suppliers and multiple manufacturers.

Science.gov (United States)

Li, Guo; Lv, Fei; Guan, Xu

2014-01-01

This paper investigates a collaborative scheduling model in the assembly system, wherein multiple suppliers have to deliver their components to the multiple manufacturers under the operation of Supply-Hub. We first develop two different scenarios to examine the impact of Supply-Hub. One is that suppliers and manufacturers make their decisions separately, and the other is that the Supply-Hub makes joint decisions with collaborative scheduling. The results show that our scheduling model with the Supply-Hub is a NP-complete problem, therefore, we propose an auto-adapted differential evolution algorithm to solve this problem. Moreover, we illustrate that the performance of collaborative scheduling by the Supply-Hub is superior to separate decision made by each manufacturer and supplier. Furthermore, we also show that the algorithm proposed has good convergence and reliability, which can be applicable to more complicated supply chain environment.

NREL Next Generation Drivetrain: Mechanical Design and Test Plan (Poster)

Energy Technology Data Exchange (ETDEWEB)

Keller, J.; Halse, C.

2014-05-01

The Department of Energy and industry partners are sponsoring a $3m project for design and testing of a 'Next Generation' wind turbine drivetrain at the National Renewable Energy Laboratory (NREL). This poster focuses on innovative aspects of the gearbox design, completed as part of an end-to-end systems engineering approach incorporating innovations that increase drivetrain reliability, efficiency, torque density and minimize capital cost.

A Web-based Tool for Transparent, Collaborative Urban Water System Planning for Monterrey, Mexico

Science.gov (United States)

Rheinheimer, D. E.; Medellin-Azuara, J.; Garza Díaz, L. E.; Ramírez, A. I.

2017-12-01

Recent rapid advances in web technologies and cloud computing show great promise for facilitating collaboration and transparency in water planning efforts. Water resources planning is increasingly in the context of a rapidly urbanizing world, particularly in developing countries. In such countries with democratic traditions, the degree of transparency and collaboration in water planning can mean the difference between success and failure of water planning efforts. This is exemplified in the city of Monterrey, Mexico, where an effort to build a new long-distance aqueduct to increase water supply to the city dramatically failed due to lack of transparency and top-down planning. To help address, we used a new, web-based water system modeling platform, called OpenAgua, to develop a prototype decision support system for water planning in Monterrey. OpenAgua is designed to promote transparency and collaboration, as well as provide strong, cloud-based, water system modeling capabilities. We developed and assessed five water management options intended to increase water supply yield and/or reliability, a dominant water management concern in Latin America generally: 1) a new long-distance source (the previously-rejected project), 2) a new nearby reservoir, 3) expansion/re-operation of an existing major canal, 4) desalination, and 5) industrial water reuse. Using the integrated modeling and analytic capabilities of OpenAgua, and some customization, we assessed the performance of these options for water supply yield and reliability to help identify the most promising ones. In presenting this assessment, we demonstrate the viability of using online, cloud-based modeling systems for improving transparency and collaboration in decision making, reducing the gap between citizens, policy makers and water managers, and future directions.

Children's meta-talk in their collaborative decision making with peers.

Science.gov (United States)

Köymen, Bahar; Tomasello, Michael

2018-02-01

In collaborative decision making, children must evaluate the evidence behind their respective claims and the rationality of their respective proposals with their partners. In the main study, 5- and 7-year-old peer dyads (N = 196) were presented with a novel animal. In the key condition, children in a dyad individually received conflicting information about what the animal needs (e.g., rocks vs. sand for food) from sources that differ in reliability (with first-hand vs. indirect evidence). Dyads in both age groups were able to reliably settle on the option with the best supporting evidence. Moreover, in making their decision, children, especially 7-year-olds, engaged in various kinds of meta-talk about the evidence and its validity. In a modified version of the key condition in Study 2, 3- and 5-year-olds (N = 120) interacted with a puppet who tried to convince children to change their minds by producing meta-talk. When the puppet insisted and produced meta-talk, 5-year-olds, but not 3-year-olds, were more likely to change their minds if their information was unreliable. These results suggest that even preschoolers can engage in collaborative reasoning successfully, but the ability to reflect on the process by stepping back to jointly examine the evidence emerges only during the early school years. Copyright © 2017 Elsevier Inc. All rights reserved.

NASA-ONERA Collaboration on Human Factors in Aviation Accidents and Incidents

Science.gov (United States)

Srivastava, Ashok N.; Fabiani, Patrick

2012-01-01

This is the first annual report jointly prepared by NASA and ONERA on the work performed under the agreement to collaborate on a study of the human factors entailed in aviation accidents and incidents, particularly focused on the consequences of decreases in human performance associated with fatigue. The objective of this agreement is to generate reliable, automated procedures that improve understanding of the levels and characteristics of flight-crew fatigue factors whose confluence will likely result in unacceptable crew performance. This study entails the analyses of numerical and textual data collected during operational flights. NASA and ONERA are collaborating on the development and assessment of automated capabilities for extracting operationally significant information from very large, diverse (textual and numerical) databases; much larger than can be handled practically by human experts.

Collaborative Prototyping

DEFF Research Database (Denmark)

Bogers, Marcel; Horst, Willem

2014-01-01

of the prototyping process, the actual prototype was used as a tool for communication or development, thus serving as a platform for the cross-fertilization of knowledge. In this way, collaborative prototyping leads to a better balance between functionality and usability; it translates usability problems into design......This paper presents an inductive study that shows how collaborative prototyping across functional, hierarchical, and organizational boundaries can improve the overall prototyping process. Our combined action research and case study approach provides new insights into how collaborative prototyping...... can provide a platform for prototype-driven problem solving in early new product development (NPD). Our findings have important implications for how to facilitate multistakeholder collaboration in prototyping and problem solving, and more generally for how to organize collaborative and open innovation...

Validation of the Impact of Health Information Technology (I-HIT) Scale: an international collaborative.

Science.gov (United States)

Dykes, Patricia C; Hurley, Ann C; Brown, Suzanne; Carr, Robyn; Cashen, Margaret; Collins, Rita; Cook, Robyn; Currie, Leanne; Docherty, Charles; Ensio, Anneli; Foster, Joanne; Hardiker, Nicholas R; Honey, Michelle L L; Killalea, Rosaleen; Murphy, Judy; Saranto, Kaija; Sensmeier, Joyce; Weaver, Charlotte

2009-01-01

In 2005, the Healthcare Information Management Systems Society (HIMSS) Nursing Informatics Community developed a survey to measure the impact of health information technology (HIT), the I-HIT Scale, on the role of nurses and interdisciplinary communication in hospital settings. In 2007, nursing informatics colleagues from Australia, England, Finland, Ireland, New Zealand, Scotland and the United States formed a research collaborative to validate the I-HIT across countries. All teams have completed construct and face validation in their countries. Five out of six teams have initiated reliability testing by practicing nurses. This paper reports the international collaborative's validation of the I-HIT Scale completed to date.

Collaborative Data Mining

Science.gov (United States)

Moyle, Steve

Collaborative Data Mining is a setting where the Data Mining effort is distributed to multiple collaborating agents - human or software. The objective of the collaborative Data Mining effort is to produce solutions to the tackled Data Mining problem which are considered better by some metric, with respect to those solutions that would have been achieved by individual, non-collaborating agents. The solutions require evaluation, comparison, and approaches for combination. Collaboration requires communication, and implies some form of community. The human form of collaboration is a social task. Organizing communities in an effective manner is non-trivial and often requires well defined roles and processes. Data Mining, too, benefits from a standard process. This chapter explores the standard Data Mining process CRISP-DM utilized in a collaborative setting.

Networking: a study in planning and developing cross-cultural collaboration

Directory of Open Access Journals (Sweden)

Sanjeev Singh

2002-12-01

Full Text Available This paper reports on a collaboration between the authors at the University of Brighton (UK and the University of Delhi, South Campus. The collaboration came about as a result of the EU-India Cross-Cultural Innovation Network collaboration programme, a project involving several universities and organizations across Europe and India. The authors of this paper both lecture in the area of computer networking. Following meetings in Delhi, they agreed to work together to produce a Web-based networking resource to be generated by the students of both institutions. The first phase of development involved the mounting of Web-based tutorials and documents produced by the students. The second phase will centre on the development of a knowledge base generated by the interaction of the students within an asynchronous forum. Running alongside these phases will be a collaborative bookmarking system, a database in which the students will post URLs of Web-based resources that they find useful in their studies. This system incorporates a form of collaborative filtering, an evolutionary mechanism which seeks to embody the qualities that students value in resources to provide a dynamic set of ratings to assist in the selection of those of most use. The planning of such a system raises some unusual issues, not least in the process of collaboration itself, with concerns as diverse as technical compatibility, institutional and cultural differences, timezones and the reliability of email. Limited bandwidth between our institutions causes special problems with the interactive elements of the resource. We present the methods we are investigating to reduce the impact of this. The fact that the students share an intellectual discipline but are otherwise separated by a cultural and geographical divide is expected to lead to fruitful diversity in thinking and approaches to problem-solving.

Supply chain process collaboration and Internet utilization: an international perspective of business to business relationships

Directory of Open Access Journals (Sweden)

Marcos Paulo Valadares de Oliveira

2015-01-01

Full Text Available This paper compiles the findings of an international study which primary objective was to investigate the relationships between Internet utilization in business-to-business relationships, collaborative efforts and their impact over supplier and customer-oriented processes performance. It highlights the Internet as an important enhancer of collaboration in supply chains and addresses the effects of such efforts on companies’ overall performance. As a conclusive-descriptive and quantitative study, data from a survey of 788 companies from the USA, China, Canada, United Kingdom, and Brazil were analyzed with the use of descriptive statistics, reliability evaluation of the research model’s internal scales, path analysis and structural equation modeling to evaluate supply chain processes collaboration, both up- and down-stream. Internet utilization in supplier and customer-oriented processes was found positively related to collaborative practices in business-to-business relationships. Collaborative practices in supplier and customer-oriented processes, in turn, showed potential effects on performance. Also, supplier-oriented processes performance was found positively associated with customer-oriented process performance. Both internet use and collaborative practices are even more important in a high-context country like Brazil. The paper helps clarify the impact of internet use on business-to-business collaborative relationships. In this sense, practitioners can take this impact to redraw the organizational landscape and business processes amongst supply chain participants.

Midwife-physician collaboration: a conceptual framework for interprofessional collaborative practice.

Science.gov (United States)

Smith, Denise Colter

2015-01-01

Since the passage of the Affordable Care Act, collaborative practice has been cited as one method of increasing access to care, decreasing costs, and improving efficiency. How and under what conditions might these goals be achieved? Midwives and physicians have built effective collaborative practice models over a period of 30 years. Empirical study of interprofessional collaboration between midwives and physicians could be useful in guiding professional education, regulation, and health policy in women's health and maternity care. Construction of a conceptual framework for interprofessional collaboration between midwives and physicians was guided by a review of the literature. A theory derivation strategy was used to define dimensions, concepts, and statements of the framework. Midwife-physician interprofessional collaboration can be defined by 4 dimensions (organizational, procedural, relational, and contextual) and 12 concepts (trust, shared power, synergy, commitment, and respect, among others). The constructed framework provides the foundation for further empirical study of the interprofessional collaborative process. The experiences of midwife-physician collaborations provide solid support for a conceptual framework of the collaborative process. A conceptual framework provides a point from which further research can increase knowledge and understanding about how successful outcomes are achieved in collaborative health care practices. Construction of a measurement scale and validation of the model are important next steps. © 2014 by the American College of Nurse-Midwives.

Supply Chain Collaboration Roles of Interorganizational Systems, Trust, and Collaborative Culture

CERN Document Server

Cao, Mei

2013-01-01

To survive and thrive in the competition, firms have strived to achieve greater supply chain collaboration to leverage the resources and knowledge of suppliers and customers.  Internet based technologies, particularly interorganizational systems, further extend the firms’ opportunities to strengthen their supply chain partnerships and share real-time information to optimize their operations.  Supply Chain Collaboration: Roles of Interorganizational Systems, Trust, and Collaborative Culture explores the nature and characteristics, antecedents, and consequences of supply chain collaboration from multiple theoretical perspectives.  Supply Chain Collaboration: Roles of Interorganizational Systems, Trust, and Collaborative Culture conceptualizes supply chain collaboration as seven interconnecting elements including information sharing, incentive alignment, goal congruence, decision synchronization, resource sharing, as well as communication and joint knowledge creation. These seven components define the occur...

Achieving High Reliability Operations Through Multi-Program Integration

Energy Technology Data Exchange (ETDEWEB)

Holly M. Ashley; Ronald K. Farris; Robert E. Richards

2009-04-01

Over the last 20 years the Idaho National Laboratory (INL) has adopted a number of operations and safety-related programs which has each periodically taken its turn in the limelight. As new programs have come along there has been natural competition for resources, focus and commitment. In the last few years, the INL has made real progress in integrating all these programs and are starting to realize important synergies. Contributing to this integration are both collaborative individuals and an emerging shared vision and goal of the INL fully maturing in its high reliability operations. This goal is so powerful because the concept of high reliability operations (and the resulting organizations) is a masterful amalgam and orchestrator of the best of all the participating programs (i.e. conduct of operations, behavior based safety, human performance, voluntary protection, quality assurance, and integrated safety management). This paper is a brief recounting of the lessons learned, thus far, at the INL in bringing previously competing programs into harmony under the goal (umbrella) of seeking to perform regularly as a high reliability organization. In addition to a brief diagram-illustrated historical review, the authors will share the INL’s primary successes (things already effectively stopped or started) and the gaps yet to be bridged.

Uncertainty Quantification in the Reliability and Risk Assessment of Generation IV Reactors: Final Scientific/Technical Report

International Nuclear Information System (INIS)

Vierow, Karen; Aldemir, Tunc

2009-01-01

The project entitled, 'Uncertainty Quantification in the Reliability and Risk Assessment of Generation IV Reactors', was conducted as a DOE NERI project collaboration between Texas A and M University and The Ohio State University between March 2006 and June 2009. The overall goal of the proposed project was to develop practical approaches and tools by which dynamic reliability and risk assessment techniques can be used to augment the uncertainty quantification process in probabilistic risk assessment (PRA) methods and PRA applications for Generation IV reactors. This report is the Final Scientific/Technical Report summarizing the project.

Uncertainty Quantification in the Reliability and Risk Assessment of Generation IV Reactors: Final Scientific/Technical Report

Energy Technology Data Exchange (ETDEWEB)

Vierow, Karen; Aldemir, Tunc

2009-09-10

The project entitled, “Uncertainty Quantification in the Reliability and Risk Assessment of Generation IV Reactors”, was conducted as a DOE NERI project collaboration between Texas A&M University and The Ohio State University between March 2006 and June 2009. The overall goal of the proposed project was to develop practical approaches and tools by which dynamic reliability and risk assessment techniques can be used to augment the uncertainty quantification process in probabilistic risk assessment (PRA) methods and PRA applications for Generation IV reactors. This report is the Final Scientific/Technical Report summarizing the project.

Reliability engineering

International Nuclear Information System (INIS)

Lee, Chi Woo; Kim, Sun Jin; Lee, Seung Woo; Jeong, Sang Yeong

1993-08-01

This book start what is reliability? such as origin of reliability problems, definition of reliability and reliability and use of reliability. It also deals with probability and calculation of reliability, reliability function and failure rate, probability distribution of reliability, assumption of MTBF, process of probability distribution, down time, maintainability and availability, break down maintenance and preventive maintenance design of reliability, design of reliability for prediction and statistics, reliability test, reliability data and design and management of reliability.

A Collaborative Scheduling Model for the Supply-Hub with Multiple Suppliers and Multiple Manufacturers

Directory of Open Access Journals (Sweden)

Guo Li

2014-01-01

Full Text Available This paper investigates a collaborative scheduling model in the assembly system, wherein multiple suppliers have to deliver their components to the multiple manufacturers under the operation of Supply-Hub. We first develop two different scenarios to examine the impact of Supply-Hub. One is that suppliers and manufacturers make their decisions separately, and the other is that the Supply-Hub makes joint decisions with collaborative scheduling. The results show that our scheduling model with the Supply-Hub is a NP-complete problem, therefore, we propose an auto-adapted differential evolution algorithm to solve this problem. Moreover, we illustrate that the performance of collaborative scheduling by the Supply-Hub is superior to separate decision made by each manufacturer and supplier. Furthermore, we also show that the algorithm proposed has good convergence and reliability, which can be applicable to more complicated supply chain environment.

A Collaborative Scheduling Model for the Supply-Hub with Multiple Suppliers and Multiple Manufacturers

Science.gov (United States)

Lv, Fei; Guan, Xu

2014-01-01

This paper investigates a collaborative scheduling model in the assembly system, wherein multiple suppliers have to deliver their components to the multiple manufacturers under the operation of Supply-Hub. We first develop two different scenarios to examine the impact of Supply-Hub. One is that suppliers and manufacturers make their decisions separately, and the other is that the Supply-Hub makes joint decisions with collaborative scheduling. The results show that our scheduling model with the Supply-Hub is a NP-complete problem, therefore, we propose an auto-adapted differential evolution algorithm to solve this problem. Moreover, we illustrate that the performance of collaborative scheduling by the Supply-Hub is superior to separate decision made by each manufacturer and supplier. Furthermore, we also show that the algorithm proposed has good convergence and reliability, which can be applicable to more complicated supply chain environment. PMID:24892104

When Collaborative Is Not Collaborative: Supporting Student Learning through Self-Surveillance

Science.gov (United States)

Kotsopoulos, Donna

2010-01-01

Collaborative learning has been widely endorsed in education. This qualitative research examines instances of collaborative learning during mathematics that were seen to be predominantly non-collaborative despite the pedagogical efforts and intentions of the teacher and the task. In an effort to disrupt the non-collaborative learning, small groups…

A phase angle based diagnostic scheme to planetary gear faults diagnostics under non-stationary operational conditions

Science.gov (United States)

Feng, Ke; Wang, Kesheng; Ni, Qing; Zuo, Ming J.; Wei, Dongdong

2017-11-01

Planetary gearbox is a critical component for rotating machinery. It is widely used in wind turbines, aerospace and transmission systems in heavy industry. Thus, it is important to monitor planetary gearboxes, especially for fault diagnostics, during its operational conditions. However, in practice, operational conditions of planetary gearbox are often characterized by variations of rotational speeds and loads, which may bring difficulties for fault diagnosis through the measured vibrations. In this paper, phase angle data extracted from measured planetary gearbox vibrations is used for fault detection under non-stationary operational conditions. Together with sample entropy, fault diagnosis on planetary gearbox is implemented. The proposed scheme is explained and demonstrated in both simulation and experimental studies. The scheme proves to be effective and features advantages on fault diagnosis of planetary gearboxes under non-stationary operational conditions.

Collaborative Dental Hygiene Practice in New Mexico and Minnesota.

Science.gov (United States)

Hodges, Kathleen O; Rogo, Ellen J; Cahoon, Allison C; Neill, Karen

2016-06-01

This descriptive, comparative study was conducted to examine characteristics, services, models and opinions among collaborative dental hygiene practitioners in New Mexico and Minnesota. A self-designed online questionnaire, distributed via SurveyMonkey®, was utilized to collect data from 73 subjects who met the inclusion criteria. A multi-phase administration process was followed. Content validity and reliability was established. Descriptive statistics were used for analysis of 6 research questions. The Mann-Whitney U, Pearson Chi-Square and Fisher's Exact tests were employed to analyze 4 null hypotheses (p=0.05). Most participants (n=36) were experienced clinicians who chose to work in an alternative setting after 28 years or more in the field and reported increased access to care as the reason for practicing collaboratively. A variety of services were offered and private insurance and Medicaid were accepted, although many practitioners did not receive direct reimbursement. The majority of New Mexico participants worked in private dental hygiene practices, earned advanced degrees and serviced Health Provider Shortage Areas. The majority of Minnesota respondents worked in various facilities, earned associate's degrees and were uncertain if Health Provider Shortage Areas were served. There were no significant differences in the variables between practitioners in both states. New Mexico and Minnesota collaborative dental hygiene practitioners are similar in characteristics, services, and opinions although models of practice vary. Collaborative dental hygiene practice is a viable answer to increasing access to care and is an option for patients who might otherwise go without care, including the unserved, underserved, uninsured and underinsured. Copyright © 2016 The American Dental Hygienists’ Association.

Exploiting Publication Contents and Collaboration Networks for Collaborator Recommendation.

Directory of Open Access Journals (Sweden)

Xiangjie Kong

Full Text Available Thanks to the proliferation of online social networks, it has become conventional for researchers to communicate and collaborate with each other. Meanwhile, one critical challenge arises, that is, how to find the most relevant and potential collaborators for each researcher? In this work, we propose a novel collaborator recommendation model called CCRec, which combines the information on researchers' publications and collaboration network to generate better recommendation. In order to effectively identify the most potential collaborators for researchers, we adopt a topic clustering model to identify the academic domains, as well as a random walk model to compute researchers' feature vectors. Using DBLP datasets, we conduct benchmarking experiments to examine the performance of CCRec. The experimental results show that CCRec outperforms other state-of-the-art methods in terms of precision, recall and F1 score.

Validation of the Thomson, Perry and Miller (2007 Collaboration Instrument in the South African context

Directory of Open Access Journals (Sweden)

Debbie Roberts

2017-02-01

Full Text Available Orientation: Collaboration is deemed important in today’s connected and complex business environment. People’s ability to collaborate with each other in organisations is becoming a business imperative. This study focuses on a valid measurement of collaboration within organisations. Research purpose: Thomson, Perry and Miller (2007 developed a collaboration measurement instrument in the United States. The aim of this study was to validate this instrument for a South African context. Motivation for the study: South African organisations face unique challenges that require optimal use of resources to improve business results. Effective collaboration is considered a powerful strategy to achieve this. Measuring the extent of collaboration can help to identify required changes in business practices. As far as could be established, there is no evidence of collaboration instruments developed and validated in South Africa. Research design, approach and method: Additional items were designed for further development of the Thomson, Perry and Miller (2007 Collaboration Instrument sub-scales, as suggested by the authors. The revised questionnaire consisting of 31 (17 existing, 14 new items was distributed electronically to 4200 employees in two organisations, with 343 valid responses received. Reliability and construct validity were tested, as was convergent validity of the norms factor with the Trust in Teams Scale. Main findings: The results of the study support a four-factor, 29-item model of collaboration when applied to a South African sample. Cronbach’s alpha ranged between 0.85 and 0.95. Confirmatory Factor Analysis fits were at an acceptable level. Convergent validity showed a moderate fit with the data. Practical/managerial implications: South African managers and human resources practitioners can utilise results to foster a collaborative environment. Contribution/value-add: This study builds on the theoretical concept of collaboration as

Spanish collaboration in the OECD Halden Reactor Project research on Gadolinia Fuel

International Nuclear Information System (INIS)

Horvath, M. I.; Jenssen, H. K.; Munoz-Reja, C.; Tverberg, T.

2011-01-01

Safe and reliable operation of nuclear power plants benefit from research and development advances and related technical solutions. One research platform is the OECD Halden Reactor Project (HRP), HRP is a joint undertaking of national organisations in 18 countries sponsoring a jointly financed programme under the auspices of the OECD-Nuclear Energy Agency (NEA). As a member state, Spain is participating HRP research programs with ENUSA as partner in the fuel research programs. Various experiments are developed and performed also by providing materials, ENUSA collaborates with HRP on various experiments investigating the fuel behaviour, especially on Gd-bearing fuel. 20 years of successful collaboration between HRP and ENUSA is continuing with promising and results to ensure and enhance the safe operation of the Spanish and all other NPPs in the world. (Author) 12 refs.

Influencia del movimiento tridimensional sobre los engranajes planetarios tipo 2KH-A en aerogeneradores. // Influence of tridimensional movement in planetary gears type 2KH-A used in gearboxes for wind turbine generator systems.

Directory of Open Access Journals (Sweden)

J. Wellesley-Bourke Funcasta

2007-09-01

Full Text Available En el trabajo se desarrolla el basamento matemático para establecer el análisis del efecto nocivo que se produce sobre losrodamientos de los mecanismos planetarios empleados en los aerogeneradores, dado esto por las condiciones variables delviento en cuanto a su velocidad y dirección.Palabras claves: Efecto giroscópico, engranajes planetarios, cargas dinámicas, energía eólica.______________________________________________________________________________AbstractIn this paper is presented the mathematical base useful to establish the analysis that deals with the noxious effect producedon the planetary mechanisms in the gearboxes for wind turbine generator systems, given by the variable conditions of thevelocity and direction of the wind.Key words: Gyroscopic effect, planetary gears, dynamic loads, wind turbine, wind energy.

Design Optimization and Evaluation of Different Wind Generator Systems

DEFF Research Database (Denmark)

Chen, Zhe; Li, Hui

2008-01-01

. In this paper, seven variable speed constant frequency (VSCF) wind generator systems are investigated, namely permanent magnet synchronous generators with the direct-driven (PMSG_DD), the single-stage gearbox (PMSG_1G) and three-stage gearbox (PMSG_3G) concepts, doubly fed induction generators with the three......With rapid development of wind power technologies and significant growth of wind power capacity installed worldwide, various wind generator systems have been developed and built. The objective of this paper is to evaluate various wind generator systems by optimization designs and comparisons......-stage gearbox (DFIG_3G) and with the single-stage gearbox (DFIG_1G), the electricity excited synchronous generator with the direct-driven (EESG_DD), and the VSCF squirrel cage induction generator with the three-stage gearbox (SCIG_3G). Firstly, the design models of wind turbines, three/single stage gearbox...

Collaborative Consumption

DEFF Research Database (Denmark)

Gjerdrum Pedersen, Esben Rahbek; Netter, Sarah

2015-01-01

Purpose – The purpose of this paper is to explore barriers and opportunities for business models based on the ideas of collaborative consumption within the fashion industry. Design/methodology/approach – The analysis is based on a multiple-case study of Scandinavian fashion libraries – a new...... to the new phenomenon of fashion libraries and does not cover other types of collaborative consumption within the fashion industry (Swap-parties, etc.). Originality/value – The paper is one of the first attempts to examine new business models of collaborative consumption in general and the fashion library...... concept in particular. The study contributes to the discussions of whether and how fashion sharing and collaboration holds promise as a viable business model and as a means to promote sustainability....

Managing collaborative design

NARCIS (Netherlands)

Sebastian, R.

2007-01-01

Collaborative design has been emerging in building projects everywhere. The more complex a building project becomes, the closer and more intensive collaboration between the design actors is required. This research focuses on collaborative design in the conceptual architecture design phase,

Collective Mind: Towards Practical and Collaborative Auto-Tuning

Directory of Open Access Journals (Sweden)

Grigori Fursin

2014-01-01

Full Text Available Empirical auto-tuning and machine learning techniques have been showing high potential to improve execution time, power consumption, code size, reliability and other important metrics of various applications for more than two decades. However, they are still far from widespread production use due to lack of native support for auto-tuning in an ever changing and complex software and hardware stack, large and multi-dimensional optimization spaces, excessively long exploration times, and lack of unified mechanisms for preserving and sharing of optimization knowledge and research material. We present a possible collaborative approach to solve above problems using Collective Mind knowledge management system. In contrast with previous cTuning framework, this modular infrastructure allows to preserve and share through the Internet the whole auto-tuning setups with all related artifacts and their software and hardware dependencies besides just performance data. It also allows to gradually structure, systematize and describe all available research material including tools, benchmarks, data sets, search strategies and machine learning models. Researchers can take advantage of shared components and data with extensible meta-description to quickly and collaboratively validate and improve existing auto-tuning and benchmarking techniques or prototype new ones. The community can now gradually learn and improve complex behavior of all existing computer systems while exposing behavior anomalies or model mispredictions to an interdisciplinary community in a reproducible way for further analysis. We present several practical, collaborative and model-driven auto-tuning scenarios. We also decided to release all material at c-mind.org/repo to set up an example for a collaborative and reproducible research as well as our new publication model in computer engineering where experimental results are continuously shared and validated by the community.

International Collaboration in the Development of NPP Software

International Nuclear Information System (INIS)

Jiang, S.; Liu, L.; Yu, H.

2015-01-01

In this paper, we first review the progress and current status of international collaboration and technical exchange in the development of nuclear power plant (NPP) software by The State Nuclear Power Software Development Center (SNPSDC) in China. Then we discuss the importance of the international collaboration and exchange in the trend of globalisation of NPP technology. We also identify the role and contribution of professional women in this process. SNPSDC, the first professional software development centre for NPP in China, has been developing COSINE — a self-reliance NPP design and analysis software product with China brand—since 2010. Through participating in OECD/NEA’s joint projects, such as ROSA-2 Project, PKL–3 Project, HYMERES Project and ATLAS Project, SNPSDC shared data with other countries involved with respect to particular areas, such as high quality reactor thermal hydraulics test data. SNPSDC’s engineers have also been actively participating in international technical and research exchange for presenting their innovative work to the community while learning from peers. Our record shows that over 30 papers have been presented in international conferences with respect to nuclear reactor thermal hydraulics, safety analysis, reactor physics and software engineering within the past 4 years. The above international collaboration and technical exchange helped SNPSDC’s engineers to keep up with the state-of-art technology in this field. The large amount of valuable experimental data transferred to SNPSDC ensured the functionality, usability and reliability of software while greatly reduced the cost and shortened the cycle of development. Female engineers and other employees of SNPSDC either drove or got actively involved in a lot of aspects of the above collaboration and exchange, such as technical communication, business negotiation and overseas affairs management. These professional women played an irreplaceable role in this project by

Formal Framework to improve the reliability of concurrent and collaborative learning games

Directory of Open Access Journals (Sweden)

Mounier

2014-05-01

Full Text Available Multi-player learning games are complex software applications resulting from a costly and complex engineering process, and involving multiple stakeholders (domain experts, teachers, game designers, programmers, testers, etc.. Moreover, they are dynamic systems that evolve over time and implement complex interactions between objects and players. Usually, once a learning game is developed, testing activities are conducted by humans who explore the possible executions of the game’s scenario to detect bugs. The complexity and the dynamic nature of multiplayer learning games enforces the complexity of testing activities. Indeed, it is impracticable to explore manually all possible executions due to their huge number. Moreover, the test cannot verify some properties on multi-player and collaborative scenarios, such as paths leading to deadlock between learners or prevent learners to meet all objectives and win the game. This type of properties should be verified at the design stage. We propose a framework enabling a formal modeling of game scenarios and an associated automatic verification of learning game’s scenario at the design stage of the development process.We use Symmetric Petri nets as a modeling language and choose to verify properties by means of model checkers. This paper discusses the possibilities offered by this framework to verify learning game’s properties before the programming stage.

Collaborative research: Accomplishments & potential

Science.gov (United States)

Katsouyanni, Klea

2008-01-01

Although a substantial part of scientific research is collaborative and increasing globalization will probably lead to its increase, very few studies actually investigate the advantages, disadvantages, experiences and lessons learned from collaboration. In environmental epidemiology interdisciplinary collaboration is essential and the contrasting geographical patterns in exposure and disease make multi-location projects essential. This paper is based on a presentation given at the Annual Conference of the International Society for Environmental Epidemiology, Paris 2006, and is attempting to initiate a discussion on a framework for studying collaborative research. A review of the relevant literature showed that indeed collaborative research is rising, in some countries with impressive rates. However, there are substantial differences between countries in their outlook, need and respect for collaboration. In many situations collaborative publications receive more citations than those based on national authorship. The European Union is the most important host of collaborative research, mainly driven by the European Commission through the Framework Programmes. A critical assessment of the tools and trends of collaborative networks under FP6, showed that there was a need for a critical revision, which led to changes in FP7. In conclusion, it is useful to study the characteristics of collaborative research and set targets for the future. The added value for science and for the researchers involved may be assessed. The motivation for collaboration could be increased in the more developed countries. Particular ways to increase the efficiency and interaction in interdisciplinary and intercultural collaboration may be developed. We can work towards "the principles of collaborative research" in Environmental Epidemiology. PMID:18208596

Systems reliability/structural reliability

International Nuclear Information System (INIS)

Green, A.E.

1980-01-01

The question of reliability technology using quantified techniques is considered for systems and structures. Systems reliability analysis has progressed to a viable and proven methodology whereas this has yet to be fully achieved for large scale structures. Structural loading variants over the half-time of the plant are considered to be more difficult to analyse than for systems, even though a relatively crude model may be a necessary starting point. Various reliability characteristics and environmental conditions are considered which enter this problem. The rare event situation is briefly mentioned together with aspects of proof testing and normal and upset loading conditions. (orig.)

A Collaborative Evaluation Framework for Biometric Connected Devices in Healthcare.

Science.gov (United States)

Farnia, Troskah; Jaulent, Marie Christine; Marchand, Guillaume; Yasini, Mobin

2017-01-01

A large number of biometric connected devices are currently available with a variety of designs. Healthcare users cannot easily choose the reliable ones that correspond the best to their healthcare problems. The existing evaluation methods do not consider at the same time aspects of connectivity and healthcare usage. In this study, a collaborative evaluation framework for biometric connected devices in healthcare usage is proposed. This framework contains six dimensions: medical validity, technical reliability, usability, ergonomy, legal compliance, and accuracy of measurements. In a first step, these dimensions were assessed by designing a self administered questionnaire answered by the stakeholders (patients, health professionals, payers, and manufacturers). A case study was then carried out in a second step to test this framework in a project of telemonitoring for heart failure patients. The results are in favor of the efficiency of the proposed framework as a decision making tool in healthcare usage.

Reliability Engineering

International Nuclear Information System (INIS)

Lee, Sang Yong

1992-07-01

This book is about reliability engineering, which describes definition and importance of reliability, development of reliability engineering, failure rate and failure probability density function about types of it, CFR and index distribution, IFR and normal distribution and Weibull distribution, maintainability and movability, reliability test and reliability assumption in index distribution type, normal distribution type and Weibull distribution type, reliability sampling test, reliability of system, design of reliability and functionality failure analysis by FTA.

Electronic Collaboration Logbook

International Nuclear Information System (INIS)

Gysin, Suzanne; Mandrichenko, Igor; Podstavkov, Vladimir; Vittone, Margherita

2012-01-01

In HEP, scientific research is performed by large collaborations of organizations and individuals. The logbook of a scientific collaboration is an important part of the collaboration record. Often it contains experimental data. At Fermi National Accelerator Laboratory (FNAL), we developed an Electronic Collaboration Logbook (ECL) application, which is used by about 20 different collaborations, experiments and groups at FNAL. The ECL is the latest iteration of the project formerly known as the Control Room Logbook (CRL). We have been working on mobile (IOS and Android) clients for the ECL. We will present the history, current status and future plans of the project, as well as design, implementation and support solutions made by the project.

The influence of learning methods on collaboration: prior repeated retrieval enhances retrieval organization, abolishes collaborative inhibition, and promotes post-collaborative memory.

Science.gov (United States)

Congleton, Adam R; Rajaram, Suparna

2011-11-01

Research on collaborative memory has unveiled the counterintuitive yet robust phenomenon that collaboration impairs group recall. A candidate explanation for this collaborative inhibition effect is the disruption of people's idiosyncratic retrieval strategies during collaboration, and it is hypothesized that employing methods that improve one's organization protects against retrieval disruption. Here it is investigated how one's learning method during the study phase--defined as either repeatedly studying or repeatedly retrieving information--influences retrieval organization and what effects this has on collaborative recall and post-collaborative individual recall. Results show that repeated retrieval consistently eliminated collaborative inhibition. This enabled participants to gain the most from re-exposure to materials recalled by their partners that they themselves did not recall and led to improvements in their individual memory following collaboration. This repeated retrieval advantage stemmed from the preferential manner in which this learning method strengthened retrieval organization. Findings are also discussed that reveal a relationship between retrieval organization and the interaction observed between learning method and short versus long delay seen in the testing effect literature. Finally, results show that the elusive benefits of cross-cuing during collaboration may be best detected with a longer study-test delay. Together, these findings illuminate when and how collaboration can enhance memory.

The engine maintenance scheduling by using reliability centered maintenance method and the identification of 5S application in PT. XYZ

Science.gov (United States)

Sembiring, N.; Panjaitan, N.; Saragih, A. F.

2018-02-01

PT. XYZ is a manufacturing company that produces fresh fruit bunches (FFB) to Crude Palm Oil (CPO) and Palm Kernel Oil (PKO). PT. XYZ consists of six work stations: receipt station, sterilizing station, thressing station, pressing station, clarification station, and kernelery station. So far, the company is still implementing corrective maintenance maintenance system for production machines where the machine repair is done after damage occurs. Problems at PT. XYZ is the absence of scheduling engine maintenance in a planned manner resulting in the engine often damaged which can disrupt the smooth production. Another factor that is the problem in this research is the kernel station environment that becomes less convenient for operators such as there are machines and equipment not used in the production area, slippery, muddy, scattered fibers, incomplete use of PPE, and lack of employee discipline. The most commonly damaged machine is in the seed processing station (kernel station) which is cake breaker conveyor machine. The solution of this problem is to propose a schedule plan for maintenance of the machine by using the method of reliability centered maintenance and also the application of 5S. The result of the application of Reliability Centered maintenance method is obtained four components that must be treated scheduled (time directed), namely: for bearing component is 37 days, gearbox component is 97 days, CBC pen component is 35 days and conveyor pedal component is 32 days While after identification the application of 5S obtained the proposed corporate environmental improvement measures in accordance with the principles of 5S where unused goods will be moved from the production area, grouping goods based on their use, determining the procedure of cleaning the production area, conducting inspection in the use of PPE, and making 5S slogans.

Learning to Collaborate by Collaborating: A Face-to-Face Collaborative Activity for Measuring and Learning Basics about Teamwork

Science.gov (United States)

Cortez, C.; Nussbaum, M.; Woywood, G.; Aravena, R.

2009-01-01

In today's fast-changing business environment, teams have emerged as a requirement for business success. However, in schools and universities, students are usually not taught teamwork skills. In this paper, we introduce learning to collaborate by collaborating, a process that enables collaboration and teamwork skills to be taught and measured…

Collaborative Consumption

DEFF Research Database (Denmark)

Gjerdrum Pedersen, Esben Rahbek; Netter, Sarah

Purpose: The purpose of this paper is to explore barriers and opportunities for business models based on the ideas of collaborative consumption within the fashion industry. Design/methodology/approach: The analysis is based on a multiple-­‐‑case study of Scandinavian fashion libraries – a new...... to the new phenomenon of fashion libraries and does not cover other types of collaborative consumption within the fashion industry (Swap-­‐‑parties, etc.). Originality/value: The paper is one of the first attempts to examine new business models of collaborative consumption in general and the fashion library...... concept in particular. The study contributes to the discussions of whether and how fashion sharing and collaboration holds promise as a viable business model and as a means to promote sustainability....

Reliability

OpenAIRE

Condon, David; Revelle, William

2017-01-01

Separating the signal in a test from the irrelevant noise is a challenge for all measurement. Low test reliability limits test validity, attenuates important relationships, and can lead to regression artifacts. Multiple approaches to the assessment and improvement of reliability are discussed. The advantages and disadvantages of several different approaches to reliability are considered. Practical advice on how to assess reliability using open source software is provided.

Persuading Collaboration: Analysing Persuasion in Online Collaboration Projects

DEFF Research Database (Denmark)

McHugh, Ronan; Larsen, Birger

2010-01-01

In this paper we propose that online collaborative production sites can be fruitfully analysed in terms of the general theoretical framework of Persuasive Design. OpenStreetMap and The Pirate Bay are used as examples of collaborative production sites. Results of a quantitative analysis of persuas...

Nurse-patient collaboration

DEFF Research Database (Denmark)

Sørensen, Dorthe; Frederiksen, Kirsten; Groefte, Thorbjoern

2013-01-01

Objectives: This paper provides a theoretical account of nurses’ collaboration with patients with chronic obstructive pulmonary disease during non-invasive ventilation treatment in hospital. Background: Despite strong evidence for the effect of non-invasive ventilation treatment, success remains...... a huge challenge. Nurse-patient collaboration may be vital for treatment tolerance and success. A better understanding of how nurses and patients collaborate during non-invasive ventilation may therefore contribute to improvement in treatment success. Design: A constant comparative classical grounded...... at three intensive care units and one general respiratory ward in Denmark. Results: Succeeding emerged as the nurses’ main concern in the nurse-patient collaboration during non-invasive ventilation treatment. Four collaborative typologies emerged as processing their main concern: (1) twofold oriented...

Global Collaborative STEM Education

Science.gov (United States)

Meabh Kelly, Susan; Smith, Walter

2016-04-01

Global Collaborative STEM Education, as the name suggests, simultaneously supports two sets of knowledge and skills. The first set is STEM -- science, technology, engineering and math. The other set of content knowledge and skills is that of global collaboration. Successful global partnerships require awareness of one's own culture, the biases embedded within that culture, as well as developing awareness of the collaborators' culture. Workforce skills fostered include open-mindedness, perseverance when faced with obstacles, and resourceful use of technological "bridges" to facilitate and sustain communication. In respect for the 2016 GIFT Workshop focus, Global Collaborative STEM Education projects dedicated to astronomy research will be presented. The projects represent different benchmarks within the Global Collaborative STEM Education continuum, culminating in an astronomy research experience that fully reflects how the global STEM workforce collaborates. To facilitate wider engagement in Global Collaborative STEM Education, project summaries, classroom resources and contact information for established international collaborative astronomy research projects will be disseminated.

Collaborative Service Arrangements

DEFF Research Database (Denmark)

J. May, Peter; Winter, Søren

While much of prior research on collaboration addresses the service delivery network as a whole, we address collaborative relationships between one type of organization—municipal employment services—and a range of governmental and non-governmental partners for employment services in Denmark....... Municipalities differ in the type, degree, and character of collaboration with these partners. As others have found in prior research, we find that organizational benefits, trust, and a variety of contextual factors help shape the extent of collaboration. But, the relevance of these and problem-solving benefits...

Improving Accuracy and Relevance of Race/Ethnicity Data: Results of a Statewide Collaboration in Hawaii.

Science.gov (United States)

Pellegrin, Karen L; Miyamura, Jill B; Ma, Carolyn; Taniguchi, Ronald

2016-01-01

Current race/ethnicity categories established by the U.S. Office of Management and Budget are neither reliable nor valid for understanding health disparities or for tracking improvements in this area. In Hawaii, statewide hospitals have collaborated to collect race/ethnicity data using a standardized method consistent with recommended practices that overcome the problems with the federal categories. The purpose of this observational study was to determine the impact of this collaboration on key measures of race/ethnicity documentation. After this collaborative effort, the number of standardized categories available across hospitals increased from 6 to 34, and the percent of inpatients with documented race/ethnicity increased from 88 to 96%. This improved standardized methodology is now the foundation for tracking population health indicators statewide and focusing quality improvement efforts. The approach used in Hawaii can serve as a model for other states and regions. Ultimately, the ability to standardize data collection methodology across states and regions will be needed to track improvements nationally.

Collaborative quality improvement.

Science.gov (United States)

Luckenbaugh, Amy N; Miller, David C; Ghani, Khurshid R

2017-07-01

Quality improvement collaboratives were developed in many medical and surgical disciplines with the goal of measuring and improving the quality of care provided to patients. The aim of this review is to provide an overview of surgical quality improvement collaboratives, and in particular those aimed at improving urological care. Quality improvement collaboratives collect high-quality data using standardized methodologies, and use the data to provide feedback to physicians and practices, and then implement processes to improve patient outcomes. The largest regional collaborative in urology is the Michigan Urological Surgery Improvement Collaborative (MUSIC). Recent efforts by this group have been focused at understanding variation in care, improving patient selection for treatment, reducing treatment morbidity and measuring and optimizing technical skill. The American Urological Association has also recently launched a national quality registry (AQUA), with an initial focus on prostate cancer care. By understanding factors that result in exemplary performance, quality improvement collaboratives are able to develop best practices around areas of care with high variation that have the potential to improve outcomes and reduce costs. These developments have been made possible by the unique model offered by the collaborative structure with the goal of improving patient care at a population level.

Online remote control systems for static and dynamic compression and decompression using diamond anvil cells

International Nuclear Information System (INIS)

Sinogeikin, Stanislav V.; Smith, Jesse S.; Rod, Eric; Lin, Chuanlong; Kenney-Benson, Curtis; Shen, Guoyin

2015-01-01

The ability to remotely control pressure in diamond anvil cells (DACs) in accurate and consistent manner at room temperature, as well as at cryogenic and elevated temperatures, is crucial for effective and reliable operation of a high-pressure synchrotron facility such as High Pressure Collaborative Access Team (HPCAT). Over the last several years, a considerable effort has been made to develop instrumentation for remote and automated pressure control in DACs during synchrotron experiments. We have designed and implemented an array of modular pneumatic (double-diaphragm), mechanical (gearboxes), and piezoelectric devices and their combinations for controlling pressure and compression/decompression rate at various temperature conditions from 4 K in cryostats to several thousand Kelvin in laser-heated DACs. Because HPCAT is a user facility and diamond cells for user experiments are typically provided by users, our development effort has been focused on creating different loading mechanisms and frames for a variety of existing and commonly used diamond cells rather than designing specialized or dedicated diamond cells with various drives. In this paper, we review the available instrumentation for remote static and dynamic pressure control in DACs and show some examples of their applications to high pressure research

Working Collaboratively

DEFF Research Database (Denmark)

Holder, Anna; Lovett, George

2009-01-01

identified as a transformative global force of the last decade, most notably in knowledge and information publishing, communication and creation. This paper presents a structured conversation on changing understandings of collaboration, and the realities of collaborative methodology in architectural work...

Collaborative Policy Innovation

DEFF Research Database (Denmark)

Sørensen, Eva; Boch Waldorff, Susanne

2014-01-01

Governments all over the Western world currently face wicked problems that call for policy innovation. A new strand of research in public innovation points to collaboration between public authorities and relevant and affected stakeholders as an important driver of public innovation. A case study...... of collaborative policy innovation in the area of mental health care in Denmark indicates that collaboration can contribute to qualify the politicians’ understanding of wicked policy problems, and to fostering new creative policy solutions. The study also shows, however, that the new problem understandings...... and policy ideas produced in collaborative governance arenas are not diffused to the formal political institutions of representative democracy because the participating politicians only to a limited extent function as boundary spanners between the collaborative governance arena and the decision making arenas...

Reliability of 3-Dimensional Measures of Single-Leg Cross Drop Landing Across 3 Different Institutions: Implications for Multicenter Biomechanical and Epidemiological Research on ACL Injury Prevention.

Science.gov (United States)

DiCesare, Christopher A; Bates, Nathaniel A; Barber Foss, Kim D; Thomas, Staci M; Wordeman, Samuel C; Sugimoto, Dai; Roewer, Benjamin D; Medina McKeon, Jennifer M; Di Stasi, Stephanie; Noehren, Brian W; Ford, Kevin R; Kiefer, Adam W; Hewett, Timothy E; Myer, Gregory D

2015-12-01

Anterior cruciate ligament (ACL) injuries are physically and financially devastating but affect a relatively small percentage of the population. Prospective identification of risk factors for ACL injury necessitates a large sample size; therefore, study of this injury would benefit from a multicenter approach. To determine the reliability of kinematic and kinetic measures of a single-leg cross drop task across 3 institutions. Controlled laboratory study. Twenty-five female high school volleyball players participated in this study. Three-dimensional motion data of each participant performing the single-leg cross drop were collected at 3 institutions over a period of 4 weeks. Coefficients of multiple correlation were calculated to assess the reliability of kinematic and kinetic measures during the landing phase of the movement. Between-centers reliability for kinematic waveforms in the frontal and sagittal planes was good, but moderate in the transverse plane. Between-centers reliability for kinetic waveforms was good in the sagittal, frontal, and transverse planes. Based on these findings, the single-leg cross drop task has moderate to good reliability of kinematic and kinetic measures across institutions after implementation of a standardized testing protocol. Multicenter collaborations can increase study numbers and generalize results, which is beneficial for studies of relatively rare phenomena, such as ACL injury. An important step is to determine the reliability of risk assessments across institutions before a multicenter collaboration can be initiated.

Theoretical foundations for collaboration engineering

NARCIS (Netherlands)

Kolfschoten, G.L.

2007-01-01

Collaboration is often presented as the solution to numerous problems in business and society. However, collaboration is challenging, and collaboration support is not an off-the-shelf-product. This research offers theoretical foundations for Collaboration Engineering. Collaboration Engineering is an

Collaborative Hierarchy.

Science.gov (United States)

Maris, Mariann

The University of Wisconsin-Milwaukee writing program is collaborative, not divisionary, as some, such as Jeanne Gunner, have suggested. Three terms are useful in understanding the relationships and ethics governing operations at Wisconsin-Milwaukee: (1) authority and collaboration; (2) hierarchical difference; (3) professional respect.…

Energy Efficiency Collaboratives

Energy Technology Data Exchange (ETDEWEB)

Li, Michael [US Department of Energy, Washington, DC (United States); Bryson, Joe [US Environmental Protection Agency, Washington, DC (United States)

2015-09-01

Collaboratives for energy efficiency have a long and successful history and are currently used, in some form, in more than half of the states. Historically, many state utility commissions have used some form of collaborative group process to resolve complex issues that emerge during a rate proceeding. Rather than debate the issues through the formality of a commission proceeding, disagreeing parties are sent to discuss issues in a less-formal setting and bring back resolutions to the commission. Energy efficiency collaboratives take this concept and apply it specifically to energy efficiency programs—often in anticipation of future issues as opposed to reacting to a present disagreement. Energy efficiency collaboratives can operate long term and can address the full suite of issues associated with designing, implementing, and improving energy efficiency programs. Collaboratives can be useful to gather stakeholder input on changing program budgets and program changes in response to performance or market shifts, as well as to provide continuity while regulators come and go, identify additional energy efficiency opportunities and innovations, assess the role of energy efficiency in new regulatory contexts, and draw on lessons learned and best practices from a diverse group. Details about specific collaboratives in the United States are in the appendix to this guide. Collectively, they demonstrate the value of collaborative stakeholder processes in producing successful energy efficiency programs.

Maturing Pump Technology for EVA Applications in a Collaborative Environment

Science.gov (United States)

Hodgson, Edward; Dionne, Steven; Gervais, Edward; Anchondo, Ian

2012-01-01

The transition from low earth orbit Extravehicular Activity (EVA) for construction and maintenance activities to planetary surface EVA on asteroids, moons, and, ultimately, Mars demands a new spacesuit system. NASA's development of that system has resulted in dramatically different pumping requirements from those in the current spacesuit system. Hamilton Sundstrand, Cascon, and NASA are collaborating to develop and mature a pump that will reliably meet those new requirements in space environments and within the design constraints imposed by spacesuit system integration. That collaboration, which began in the NASA purchase of a pump prototype for test evaluation, is now entering a new phase of development. A second generation pump reflecting the lessons learned in NASA's testing of the original prototype will be developed under Hamilton Sundstrand internal research funding and ultimately tested in an integrated Advanced Portable Life Support System (APLSS) in NASA laboratories at the Johnson Space Center. This partnership is providing benefit to both industry and NASA by supplying a custom component for EVA integrated testing at no cost to the government while providing test data for industry that would otherwise be difficult or impossible to duplicate in industry laboratories. This paper discusses the evolving collaborative process, component requirements and design development based on early NASA test experience, component stand alone test results, and near term plans for integrated testing at JSCs.

Trust repertoires for collaboration

DEFF Research Database (Denmark)

Fuglsang, Lars

This case study analyses the role of trust in a public private innovation network that involved a private consultancy company as a facilitator. We know that collaboration is a important for innovation, and that collaboration across organizational boundaries is not a trivial issue. But we know very...... little about how such processes develop and how trust, understood as “confident positive expectations” (Lewicki et al. 1998) to collaborative activities, arises out of collaboration. The paper contributes by showing how trust and collaboration are intertwined. The main finding is that a facilitator can...

Collaborative exams: Cheating? Or learning?

Science.gov (United States)

Jang, Hyewon; Lasry, Nathaniel; Miller, Kelly; Mazur, Eric

2017-03-01

Virtually all human activity involves collaboration, and yet, collaboration during an examination is typically considered cheating. Collaborative assessments have not been widely adopted because of the perceived lack of individual accountability and the notion that collaboration during assessments simply causes propagation of correct answers. Hence, collaboration could help weaker students without providing much benefit to stronger students. In this paper, we examine student performance in open-ended, two-stage collaborative assessments comprised of an individually accountable round followed by an automatically scored, collaborative round. We show that collaboration entails more than just propagation of correct answers. We find greater rates of correct answers after collaboration for all students, including the strongest members of a team. We also find that half of teams that begin without a correct answer to propagate still obtain the correct answer in the collaborative round. Our findings, combined with the convenience of automatic feedback and grading of open-ended questions, provide a strong argument for adopting collaborative assessments as an integral part of education.

Collaborative Learning in the Cloud

DEFF Research Database (Denmark)

Kirchner, Kathrin; Razmerita, Liana

2015-01-01

This present study aims to investigate how students perceive collaboration and identifies associated technologies used to collaborate. In particular we aim to address the following research questions: What are the factors that impact satisfaction with collaboration? How do these factors differ in...... in different collaborative settings? Based on data from 75 students from Denmark and Germany, the article identifies collaborative practices and factors that impact positively and negatively satisfaction with collaboration....

Noise pollution from wind turbine gears loudness of structural noise sources related to gears

International Nuclear Information System (INIS)

Crone, A.

1995-04-01

The purpose of the project has been to develop a method for determination of the structure-borne noise source strength of the gearbox in a typical modern Danish wind turbine construction, with special reference to the tonal noise emission form the turbines. Through study and evaluation of eight potential methods, a simple method has ben formulated. The method is based on measurements of the free vibration velocity level on the gearbox in a load test bed. The relation between this source strength measure and the gearbox related noise from wind turbines has been documented by measurements made during the project together with earlier measurements. The method is intended as a tool for the wind turbine manufacturer, for control of the gearbox related noise from the wind turbines, due to structure-borne noise from the gearbox. It may be used for preparation of specifications to the gearbox manufacturer on test procedure and acceptable source strength levels. Also, it may be used for evaluation of the transmission and radiation of gearbox related noise, for example in order to uncover weaknesses in a prototype turbine. Suggestions for adaptation and evolution of the method has been given, thereby improving the strength of the method for the individual wind turbine manufacturer. (au) 19 refs

The Collaborative Future

Directory of Open Access Journals (Sweden)

Thomas Marlowe

2011-10-01

Full Text Available Collaboration has become an important goal in modern ventures, across the spectrum of commercial, social, and intellectual activities, sometimes as a mediating factor, and sometimes as a driving, foundational principle. Research, development, social programs, and ongoing ventures of all sorts benefit from interactions between teams, groups, and organizations, across intellectual disciplines and across facets and features of the inquiry, product, entity, or activity under consideration. We present a survey of the state of collaboration and collaborative enterprise, in the context of papers and presentations at the International Symposium on Collaborative Enterprises 2011 (CENT 2011, and the extended papers appearing in this special issue.

75 FR 42340 - Airworthiness Directives; Sikorsky Aircraft Corporation (Sikorsky) Model S-92A Helicopters

Science.gov (United States)

2010-07-21

... the main gearbox housing and replacing any main gearbox housing that exceeds the life limit. This... housing that exceeds the lower life limit. This proposal is prompted by review of a fatigue analysis... reduce the life limit of the main gearbox housing from 2700 hours TIS to 1000 hours TIS and replacing...

Transparency in a Pediatric Quality Improvement Collaborative: A Passionate Journey by NPC-QIC Clinicians and Parents.

Science.gov (United States)

Lihn, Stacey L; Kugler, John D; Peterson, Laura E; Lannon, Carole M; Pickles, Diane; Beekman, Robert H

2015-01-01

Transparency-sharing data or information about outcomes, processes, protocols, and practices-may be the most powerful driver of health care improvement. In this special article, the development and growth of transparency within the National Pediatric Cardiology Quality Improvement Collaborative is described. The National Pediatric Cardiology Quality Improvement Collaborative transparency journey is guided by equal numbers of clinicians and parents of children with congenital heart disease working together in a Transparency Work Group. Activities are organized around four interrelated levels of transparency (individual, organizational, collaborative, and system), each with a specified purpose and aim. A number of Transparency Work Group recommendations have been operationalized. Aggregate collaborative performance is now reported on the public-facing web site. Specific information that the Transparency Work Group recommends centers provide to parents has been developed and published. Almost half of National Pediatric Cardiology Quality Improvement Collaborative centers participated in a pilot of transparently sharing their outcomes achieved with one another. Individual centers have also begun successfully implementing recommended transparency activities. Despite progress, barriers to full transparency persist, including health care organization concerns about potential negative effects of disclosure on reputation and finances, and lack of reliable definitions, data, and reporting standards for fair comparisons of centers. The National Pediatric Cardiology Quality Improvement Collaborative's transparency efforts have been a journey that continues, not a single goal or destination. Balanced participation of clinicians and parents has been a critical element of the collaborative's success on this issue. Plans are in place to guide implementation of additional transparency recommendations across all four levels, including extension of the activities beyond the

Mammography image assessment; validity and reliability of current scheme

International Nuclear Information System (INIS)

Hill, C.; Robinson, L.

2015-01-01

Mammographers currently score their own images according to criteria set out by Regional Quality Assurance. The criteria used are based on the ‘Perfect, Good, Moderate, Inadequate’ (PGMI) marking criteria established by the National Health Service Breast Screening Programme (NHSBSP) in their Quality Assurance Guidelines of 2006 1 . This document discusses the validity and reliability of the current mammography image assessment scheme. Commencing with a critical review of the literature this document sets out to highlight problems with the national approach to the use of marking schemes. The findings suggest that ‘PGMI’ scheme is flawed in terms of reliability and validity and is not universally applied across the UK. There also appear to be differences in schemes used by trainees and qualified mammographers. Initial recommendations are to be made in collaboration with colleagues within the National Health Service Breast Screening Programme (NHSBSP), Higher Education Centres, College of Radiographers and the Royal College of Radiologists in order to identify a mammography image appraisal scheme that is fit for purpose. - Highlights: • Currently no robust evidence based marking tools in use for the assessment of images in mammography. • Is current system valid, reliable and robust? • How can the current image assessment tool be improved? • Should students and qualified mammographers use the same tool? • What marking criteria are available for image assessment?

The computer vision in the service of safety and reliability in steam generators inspection services

International Nuclear Information System (INIS)

Pineiro Fernandez, P.; Garcia Bueno, A.; Cabrera Jordan, E.

2012-01-01

The actual computational vision has matured very quickly in the last ten years by facilitating new developments in various areas of nuclear application allowing to automate and simplify processes and tasks, instead or in collaboration with the people and equipment efficiently. The current computer vision (more appropriate than the artificial vision concept) provides great possibilities of also improving in terms of the reliability and safety of NPPS inspection systems.

Petroleum R and D collaboration

International Nuclear Information System (INIS)

Kerr, R.

1995-01-01

Conditions for collaboration in research and development (R and D) were developed based on a decision-tree analysis. A key requirement for effective R and D collaboration was stated to be the company's ability to internalize a significant portion of the benefits. This was seen as the principal factor that determined good collaborators and good industries for collaboration. It was noted that collaboration benefits can also be improved through R and D exchanges in collaborative associations. Simple decision-tree analysis tended to understate the advantages of collaboration. Portfolio risk reduction and inter-project synergies were significant additional advantages. Collaborative R and D was said to be the preferred route for the development of a broad base of petroleum-related technologies. 5 tabs., 2 figs

Managing collaborative design

OpenAIRE

Sebastian, R.

2007-01-01

Collaborative design has been emerging in building projects everywhere. The more complex a building project becomes, the closer and more intensive collaboration between the design actors is required. This research focuses on collaborative design in the conceptual architecture design phase, especially during the elaboration of the masterplan and the development of the preliminary building designs. This research is descriptive and has two aims. First, it aims at describing the characteristics a...

The Diagnostic System of A – 604 Automatic Transmission

Directory of Open Access Journals (Sweden)

Czaban Jaroslaw

2014-09-01

Full Text Available Automatic gearbox gains increasing popularity in Europe. Little interest in diagnosis of such type of transmission in Poland results from the fact of small share in the whole market of operated cars, so there is a lack of availability of special diagnostic devices. These factors cause issues of expensive repairs, often involving a replacement of subassembly to new or aftermarket one. To a small extent some prophylactic diagnostic tests are conducted, which can eliminate future gearbox system failures. In the paper, the proposition of diagnostic system of popular A - 604 gearbox was presented. The authors are seeking for the possibility of using such type of devices to functional elaboration of gearboxes after renovation. The built system pursues the drive of the researched object, connected with simulated load, where special controller, replacing the original one, is responsible for controlling gearbox operation. This way is used to evaluate the mechanic and hydraulic parts' state. Analysis of signal runs, registered during measurements lets conclude about operation correctness, where as comparison with stock data verifies the technical state of an automatic gearbox.

Collaborative networks: Reference modeling

NARCIS (Netherlands)

Camarinha-Matos, L.M.; Afsarmanesh, H.

2008-01-01

Collaborative Networks: Reference Modeling works to establish a theoretical foundation for Collaborative Networks. Particular emphasis is put on modeling multiple facets of collaborative networks and establishing a comprehensive modeling framework that captures and structures diverse perspectives of

Wind turbine integrated multipole permanent magnet generator (PMG)

Energy Technology Data Exchange (ETDEWEB)

Vilsboell, N.; Pinegin, A.; Goussarov, D.

1996-01-01

Designed permanent magnet generator (PMG - 20 kW) possesses a number of advantages: it makes possible to replace gearbox, the generator and possibly the hub of the wind turbine by combining wind rotor with external rotor of the generator; use of rare earth magnets Nd-Fe-B allows to reduce mass and dimensions of the generator; use of the PMG for wind turbines increases the reliability of the construction during the life time, comparing to the conventional design (gearbox, asynchronous generator). The test of the PMG -20 kW informs that design method, developed for calculation of multipole permanent magnet generators is correct in general and meets engineering requirements. The calculation uncertainty of the magnetic system and output characteristics does not exceed 2-3%. The test shows, that the maximum efficiency of the PGM - 20 kW with full load can be achieved as high as 90-91.5% and excels the efficiency of the traditional system `generator-gearbox` by 4-5.5%. Designing permanent magnet generator, it is recommended to take into account voltage stabilization (capacitance). Efficiency is expected to be higher, mass and production cost of the generator can be reduced by 25-30%. The frequency converter shall be used not only for control of rotational speed, but also to obtain sinusoidal capacitive current on the generator side. For PMG - 20 kW the angle between voltage and current should be within the range 0-23%. (au)

Assessing Online Collaborative Discourse.

Science.gov (United States)

Breen, Henny

2015-01-01

This qualitative study using transcript analysis was undertaken to clarify the value of Harasim's Online Collaborative Learning Theory as a way to assess the collaborative process within nursing education. The theory incorporated three phases: (a) idea generating; (b) idea organizing; and (c) intellectual convergence. The transcripts of asynchronous discussions from a 2-week module about disaster nursing using a virtual community were analyzed and formed the data for this study. This study supports the use of Online Collaborative Learning Theory as a framework for assessing online collaborative discourse. Individual or group outcomes were required for the students to move through all three phases of the theory. The phases of the Online Collaborative Learning Theory could be used to evaluate the student's ability to collaborate. It is recommended that group process skills, which have more to do with interpersonal skills, be evaluated separately from collaborative learning, which has more to do with cognitive skills. Both are required for practicing nurses. When evaluated separately, the student learning needs are more clearly delineated. © 2014 Wiley Periodicals, Inc.

Collaboration across the Arctic

DEFF Research Database (Denmark)

Huppert, Verena Gisela; Chuffart, Romain François R.

2017-01-01

The Arctic is witnessing the rise of a new paradigm caused by an increase in pan-Arctic collaborations which co-exist with the region’s traditional linkages with the South. Using an analysis of concrete examples of regional collaborations in the Arctic today in the fields of education, health...... and infrastructure, this paper questions whether pan-Arctic collaborations in the Arctic are more viable than North-South collaborations, and explores the reasons behind and the foreseeable consequences of such collaborations. It shows that the newly emerging East-West paradigm operates at the same time...... as the traditional North-South paradigm, with no signs of the East-West paradigm being more viable in the foreseeable future. However, pan-Arctic collaboration, both due to pragmatic reasons and an increased awareness of similarities, is likely to increase in the future. The increased regionalization process...

What are the barriers and facilitators to implementing Collaborative Care for depression? A systematic review.

Science.gov (United States)

Wood, Emily; Ohlsen, Sally; Ricketts, Thomas

2017-05-01

Collaborative Care is an evidence-based approach to the management of depression within primary care services recommended within NICE Guidance. However, uptake within the UK has been limited. This review aims to investigate the barriers and facilitators to implementing Collaborative Care. A systematic review of the literature was undertaken to uncover what barriers and facilitators have been reported by previous research into Collaborative Care for depression in primary care. The review identified barriers and facilitators to successful implementation of Collaborative Care for depression in 18 studies across a range of settings. A framework analysis was applied using the Collaborative Care definition. The most commonly reported barriers related to the multi-professional approach, such as staff and organisational attitudes to integration, and poor inter-professional communication. Facilitators to successful implementation particularly focussed on improving inter-professional communication through standardised care pathways and case managers with clear role boundaries and key underpinning personal qualities. Not all papers were independent title and abstract screened by multiple reviewers thus limiting the reliability of the selected studies. There are many different frameworks for assessing the quality of qualitative research and little consensus as to which is most appropriate in what circumstances. The use of a quality threshold led to the exclusion of six papers that could have included further information on barriers and facilitators. Although the evidence base for Collaborative Care is strong, and the population within primary care with depression is large, the preferred way to implement the approach has not been identified. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Multinomial-exponential reliability function: a software reliability model

International Nuclear Information System (INIS)

Saiz de Bustamante, Amalio; Saiz de Bustamante, Barbara

2003-01-01

The multinomial-exponential reliability function (MERF) was developed during a detailed study of the software failure/correction processes. Later on MERF was approximated by a much simpler exponential reliability function (EARF), which keeps most of MERF mathematical properties, so the two functions together makes up a single reliability model. The reliability model MERF/EARF considers the software failure process as a non-homogeneous Poisson process (NHPP), and the repair (correction) process, a multinomial distribution. The model supposes that both processes are statistically independent. The paper discusses the model's theoretical basis, its mathematical properties and its application to software reliability. Nevertheless it is foreseen model applications to inspection and maintenance of physical systems. The paper includes a complete numerical example of the model application to a software reliability analysis

Collaborative applied research programs at AITF

Energy Technology Data Exchange (ETDEWEB)

Chow, Ross [Alberta Innovates Technology Futures (Canada)

2011-07-01

Alberta Innovates Technology Futures (AITF) is a 600 employee company created in 2010 and owned by the Alberta government; offices are located in Edmonton, Devon, Vegreville and Calgary. The purpose of this document is to present the services provided by AITF. The company provides technical support and advisory services as well as commercialization support, they provide the link between the concept stage and the commercialization stage. AITF proposes collaborative programs which can be consortia made up of a series of projects on general industry issues or joint industry projects which focus on a specific issue. During this presentation, a joint industry project, the fuels and lubricants exchange program, was presented along with several consortia such as the carbonate research program, the materials and reliability in oil sands program, and the AACI program. This presentation highlighted the work carried out by AITF to meet the needs of their clients.

Development and pilot testing the Family Conference Rating Scale: A tool aimed to assess interprofessional patient-centred communication and collaboration competencies.

Science.gov (United States)

Dojeiji, Sue; Byszewski, Anna; Wood, Tim

2015-01-01

There is a paucity of evidence-based literature on the essential communication and collaboration skills to guide health care teams in conducting and assessing their performance in the Family Conference (FC). The authors developed and collected validity evidence for a rating scale of team FC performance, the Family Conference Rating Scale (FCRS). In phase 1, essential FC communication and collaboration skills were identified through a review of existing communication tools and literature on team functioning; a draft 34-item scale was developed. In phase 2, the scale was narrowed to a 6-category, 9-point scale with descriptors of expected behaviours through an iterative process: testing of the scale on 10 FC transcripts by two experts, soliciting feedback from a focus group of seven health care providers, and testing by non-experts on 49 live FCs. In phase 3, scores on the revised scale were validated by 10 health care providers from different disciplines by rating three videos of FCs of variable quality. Raters were able to detect inter-video variation in FC quality. The reliability of the FCRS was 0.95 and the inter-rater reliability, 0.68. The FCRS may enhance the ability of health professions educators to teach and assess interprofessional patient-centred communication and collaboration competencies.

Collaborative Windows – A User Interface Concept for Distributed Collaboration

DEFF Research Database (Denmark)

Esbensen, Morten

2016-01-01

where close collaboration and frequent meetings drive the work. One way to achieve this way of working is to implement the Scrum software development framework. Implementing Scrum in globalized context however, requires transforming the Scrum development methods to a distributed setup and extensive use...... of collaboration technologies. In this dissertation, I explore how novel collaboration technologies can support closely coupled distributed work such as that in distributed Scrum. This research is based on three different studies: an ethnographic field study of distributed Scrum between Danish and Indian software...

Adaptive Collaboration Support Systems : Designing Collaboration Support for Dynamic Environments

NARCIS (Netherlands)

Janeiro, J.; Knoll, S.W.; Lukosch, S.G.; Kolfschoten, G.L.

2012-01-01

Today, engineering systems offer a variety of local and webbased applications to support collaboration by assisting groups in structuring activities, generating and sharing data, and improving group communication. To ensure the quality of collaboration, engineering system design needs to analyze and

Multicenter collaborative for orthopaedic research in India: An opportunity for global leadership

Directory of Open Access Journals (Sweden)

Mathew George

2008-01-01

Full Text Available Road traffic accidents are increasing at an alarming rate and have become a major public health concern in India. In addition, there is a lack of trauma research output and reliable data from India. There are several issues and challenges that have presented an opportunity for researchers and surgeons in India to develop a collaborative aimed at improving the quality and productivity of orthopaedic trauma research. Establishing a network of surgical researchers across India is a necessary first step towards global leadership in orthopaedic surgery trials.

reliability reliability

African Journals Online (AJOL)

eobe

Corresponding author, Tel: +234-703. RELIABILITY .... V , , given by the code of practice. However, checks must .... an optimization procedure over the failure domain F corresponding .... of Concrete Members based on Utility Theory,. Technical ...

Tritium test of the tritium processing components under the Annex III US-Japan Collaboration

International Nuclear Information System (INIS)

Konishi, Satoshi; Yoshida, Hiroshi; Naruse, Yuji; Binning, K.E.; Carlson, R.V.; Bartlit, J.R.; Anderson, J.L.

1993-03-01

The process ready components for Fuel Cleanup System were tested at the TSTA under the US-Japan Collaboration program. Palladium diffuser for tritium purification and Ceramic Electrolysis Cell for decomposition of tritiated water respectively were tested with pure tritium for years. The characteristics of the components with hydrogen isotopes, effects of impurities, and long-term reliability of the components were studied. It was concluded that these components are suitable and attractive for fusion fuel processing systems. (author)

Size Reduction Techniques for Large Scale Permanent Magnet Generators in Wind Turbines

Science.gov (United States)

Khazdozian, Helena; Hadimani, Ravi; Jiles, David

2015-03-01

Increased wind penetration is necessary to reduce U.S. dependence on fossil fuels, combat climate change and increase national energy security. The U.S Department of Energy has recommended large scale and offshore wind turbines to achieve 20% wind electricity generation by 2030. Currently, geared doubly-fed induction generators (DFIGs) are typically employed in the drivetrain for conversion of mechanical to electrical energy. Yet, gearboxes account for the greatest downtime of wind turbines, decreasing reliability and contributing to loss of profit. Direct drive permanent magnet generators (PMGs) offer a reliable alternative to DFIGs by eliminating the gearbox. However, PMGs scale up in size and weight much more rapidly than DFIGs as rated power is increased, presenting significant challenges for large scale wind turbine application. Thus, size reduction techniques are needed for viability of PMGs in large scale wind turbines. Two size reduction techniques are presented. It is demonstrated that 25% size reduction of a 10MW PMG is possible with a high remanence theoretical permanent magnet. Additionally, the use of a Halbach cylinder in an outer rotor PMG is investigated to focus magnetic flux over the rotor surface in order to increase torque. This work was supported by the National Science Foundation under Grant No. 1069283 and a Barbara and James Palmer Endowment at Iowa State University.

Measuring reliability under epistemic uncertainty: Review on non-probabilistic reliability metrics

Directory of Open Access Journals (Sweden)

Kang Rui

2016-06-01

Full Text Available In this paper, a systematic review of non-probabilistic reliability metrics is conducted to assist the selection of appropriate reliability metrics to model the influence of epistemic uncertainty. Five frequently used non-probabilistic reliability metrics are critically reviewed, i.e., evidence-theory-based reliability metrics, interval-analysis-based reliability metrics, fuzzy-interval-analysis-based reliability metrics, possibility-theory-based reliability metrics (posbist reliability and uncertainty-theory-based reliability metrics (belief reliability. It is pointed out that a qualified reliability metric that is able to consider the effect of epistemic uncertainty needs to (1 compensate the conservatism in the estimations of the component-level reliability metrics caused by epistemic uncertainty, and (2 satisfy the duality axiom, otherwise it might lead to paradoxical and confusing results in engineering applications. The five commonly used non-probabilistic reliability metrics are compared in terms of these two properties, and the comparison can serve as a basis for the selection of the appropriate reliability metrics.

Multiuser Collaboration with Networked Mobile Devices

Science.gov (United States)

Tso, Kam S.; Tai, Ann T.; Deng, Yong M.; Becks, Paul G.

2006-01-01

In this paper we describe a multiuser collaboration infrastructure that enables multiple mission scientists to remotely and collaboratively interact with visualization and planning software, using wireless networked personal digital assistants(PDAs) and other mobile devices. During ground operations of planetary rover and lander missions, scientists need to meet daily to review downlinked data and plan science activities. For example, scientists use the Science Activity Planner (SAP) in the Mars Exploration Rover (MER) mission to visualize downlinked data and plan rover activities during the science meetings [1]. Computer displays are projected onto large screens in the meeting room to enable the scientists to view and discuss downlinked images and data displayed by SAP and other software applications. However, only one person can interact with the software applications because input to the computer is limited to a single mouse and keyboard. As a result, the scientists have to verbally express their intentions, such as selecting a target at a particular location on the Mars terrain image, to that person in order to interact with the applications. This constrains communication and limits the returns of science planning. Furthermore, ground operations for Mars missions are fundamentally constrained by the short turnaround time for science and engineering teams to process and analyze data, plan the next uplink, generate command sequences, and transmit the uplink to the vehicle [2]. Therefore, improving ground operations is crucial to the success of Mars missions. The multiuser collaboration infrastructure enables users to control software applications remotely and collaboratively using mobile devices. The infrastructure includes (1) human-computer interaction techniques to provide natural, fast, and accurate inputs, (2) a communications protocol to ensure reliable and efficient coordination of the input devices and host computers, (3) an application

Providers’ perspectives on collaboration

Directory of Open Access Journals (Sweden)

Patricia Bruner

2011-08-01

Full Text Available Objective: Changes in models of health care are required to better meet the needs of diverse, underserved patient populations. Collaboration among providers is one way to promote accessible, comprehensive and continuous care in healthcare organizations. This paper describes the quantitative findings from two time points that examined providers' views of collaboration among a sample of diverse personnel (e.g. clinical nurses, social workers, dental providers, mental health providers, clerical staff, medical assistants, public health staff, and administrators within a federally qualified nurse managed health care centre in the United States. Methods: The quantitative arm of a mixed-method study is presented in this paper. Two instruments, the Collaboration and Satisfaction About Care Decisions Scale and the University of the West of England Interprofessional Questionnaire (comprised of 4 subscales-Communication and Teamwork Scale, Interprofessional Learning Scale, Interprofessional Interaction Scale, and Interprofessional Relationships Scale were administered to providers at baseline and three to eight months following six same discipline focus group discussions on collaboration, in order to evaluate whether participating in the focus group discussions changed providers' views of collaboration. A summary of the focus group data which were published elsewhere is additionally summarized to help provide insight to the quantitative findings. Thirty-nine staff participated. Results: Paired t-tests revealed that only one scale out of the five, Collaboration and Satisfaction About Care Decisions Scale (33.97 at time one and 37.45 at time two, significantly and positively changed after the focus group discussion (p=0.046. Providers' views on collaboration ranged from positive to moderate views of collaboration; most measures revealed a non-significant improvement after the focus group discussions. Staff with some graduate school reported the greatest

Providers’ perspectives on collaboration

Directory of Open Access Journals (Sweden)

Patricia Bruner

2011-08-01

Full Text Available Objective: Changes in models of health care are required to better meet the needs of diverse, underserved patient populations. Collaboration among providers is one way to promote accessible, comprehensive and continuous care in healthcare organizations. This paper describes the quantitative findings from two time points that examined providers' views of collaboration among a sample of diverse personnel (e.g. clinical nurses, social workers, dental providers, mental health providers, clerical staff, medical assistants, public health staff, and administrators within a federally qualified nurse managed health care centre in the United States.Methods: The quantitative arm of a mixed-method study is presented in this paper. Two instruments, the Collaboration and Satisfaction About Care Decisions Scale and the University of the West of England Interprofessional Questionnaire (comprised of 4 subscales-Communication and Teamwork Scale, Interprofessional Learning Scale, Interprofessional Interaction Scale, and Interprofessional Relationships Scale were administered to providers at baseline and three to eight months following six same discipline focus group discussions on collaboration, in order to evaluate whether participating in the focus group discussions changed providers' views of collaboration. A summary of the focus group data which were published elsewhere is additionally summarized to help provide insight to the quantitative findings. Thirty-nine staff participated.Results: Paired t-tests revealed that only one scale out of the five, Collaboration and Satisfaction About Care Decisions Scale (33.97 at time one and 37.45 at time two, significantly and positively changed after the focus group discussion (p=0.046. Providers' views on collaboration ranged from positive to moderate views of collaboration; most measures revealed a non-significant improvement after the focus group discussions. Staff with some graduate school reported the greatest

Collaborative Economy

DEFF Research Database (Denmark)

things, de-industrialization processes and post-capitalist forms of production and consumption, postmaterialism, the rise of the third sector and collaborative governance. Addressing that gap, this book explores the character, depth and breadth of these disruptions, the creative opportunities for tourism...... that are emerging from them, and how governments are responding to these new challenges. In doing so, the book provides both theoretical and practical insights into the future of tourism in a world that is, paradoxically, becoming both increasingly collaborative and individualized. Table of Contents Preface 1.The......This book employs an interdisciplinary, cross-sectoral lens to explore the collaborative dynamics that are currently disrupting, re-creating and transforming the production and consumption of tourism. House swapping, ridesharing, voluntourism, couchsurfing, dinner hosting, social enterprise...

Reliability Approach of a Compressor System using Reliability Block ...

African Journals Online (AJOL)

pc

2018-03-05

Mar 5, 2018 ... This paper presents a reliability analysis of such a system using reliability ... Keywords-compressor system, reliability, reliability block diagram, RBD .... the same structure has been kept with the three subsystems: air flow, oil flow and .... and Safety in Engineering Design", Springer, 2009. [3] P. O'Connor ...

The collaborative Economy and Tourism

DEFF Research Database (Denmark)

Dredge, Dianne; Gyimóthy, Szilvia

2015-01-01

House swapping, ridesharing, voluntourism, couchsurfing, dinner hosting and similar innovations epitomize the collaborative economy. The rise of the collaborative economy, also known as collaborative consumption, the sharing economy and peer-to-peer consumption, has been fuelled by a range of soc...... for a balanced assessment of such claims. Highlighting these claims allows us to pursue a more reflective research agenda and leads to a more informed, evidence-based assessment of the collaborative economy and tourism.......House swapping, ridesharing, voluntourism, couchsurfing, dinner hosting and similar innovations epitomize the collaborative economy. The rise of the collaborative economy, also known as collaborative consumption, the sharing economy and peer-to-peer consumption, has been fuelled by a range...... experiences; and higher levels of consumer risk-taking balanced against mechanisms such as peer-to-peer feedback designed to engender trust between producers and consumers. This paper explores and critically assesses the collaborative economy and its implications for tourism industrial systems. It achieves...

Frontiers of reliability

CERN Document Server

Basu, Asit P; Basu, Sujit K

1998-01-01

This volume presents recent results in reliability theory by leading experts in the world. It will prove valuable for researchers, and users of reliability theory. It consists of refereed invited papers on a broad spectrum of topics in reliability. The subjects covered include Bayesian reliability, Bayesian reliability modeling, confounding in a series system, DF tests, Edgeworth approximation to reliability, estimation under random censoring, fault tree reduction for reliability, inference about changes in hazard rates, information theory and reliability, mixture experiment, mixture of Weibul

Software reliability

CERN Document Server

Bendell, A

1986-01-01

Software Reliability reviews some fundamental issues of software reliability as well as the techniques, models, and metrics used to predict the reliability of software. Topics covered include fault avoidance, fault removal, and fault tolerance, along with statistical methods for the objective assessment of predictive accuracy. Development cost models and life-cycle cost models are also discussed. This book is divided into eight sections and begins with a chapter on adaptive modeling used to predict software reliability, followed by a discussion on failure rate in software reliability growth mo

Experiences of Collaborative Research

Science.gov (United States)

Kahneman, Daniel

2003-01-01

The author's personal history of the research that led to his recognition in economics is described, focusing on the process of collaboration and on the experience of controversy. The author's collaboration with Amos Tversky dealt with 3 major topics: judgment under uncertainty, decision making, and framing effects. A subsequent collaboration,…

Research on the time optimization model algorithm of Customer Collaborative Product Innovation

Directory of Open Access Journals (Sweden)

Guodong Yu

2014-01-01

Full Text Available Purpose: To improve the efficiency of information sharing among the innovation agents of customer collaborative product innovation and shorten the product design cycle, an improved genetic annealing algorithm of the time optimization was presented. Design/methodology/approach: Based on the analysis of the objective relationship between the design tasks, the paper takes job shop problems for machining model and proposes the improved genetic algorithm to solve the problems, which is based on the niche technology and thus a better product collaborative innovation design time schedule is got to improve the efficiency. Finally, through the collaborative innovation design of a certain type of mobile phone, the proposed model and method were verified to be correct and effective. Findings and Originality/value: An algorithm with obvious advantages in terms of searching capability and optimization efficiency of customer collaborative product innovation was proposed. According to the defects of the traditional genetic annealing algorithm, the niche genetic annealing algorithm was presented. Firstly, it avoided the effective gene deletions at the early search stage and guaranteed the diversity of solution; Secondly, adaptive double point crossover and swap mutation strategy were introduced to overcome the defects of long solving process and easily converging local minimum value due to the fixed crossover and mutation probability; Thirdly, elite reserved strategy was imported that optimal solution missing was avoided effectively and evolution speed was accelerated. Originality/value: Firstly, the improved genetic simulated annealing algorithm overcomes some defects such as effective gene easily lost in early search. It is helpful to shorten the calculation process and improve the accuracy of the convergence value. Moreover, it speeds up the evolution and ensures the reliability of the optimal solution. Meanwhile, it has obvious advantages in efficiency of

CERAPP: Collaborative estrogen receptor activity prediction project

DEFF Research Database (Denmark)

Mansouri, Kamel; Abdelaziz, Ahmed; Rybacka, Aleksandra

2016-01-01

). Risk assessors need tools to prioritize chemicals for evaluation in costly in vivo tests, for instance, within the U.S. EPA Endocrine Disruptor Screening Program. oBjectives: We describe a large-scale modeling project called CERAPP (Collaborative Estrogen Receptor Activity Prediction Project...... States and Europe to predict ER activity of a common set of 32,464 chemical structures. Quantitative structure-activity relationship models and docking approaches were employed, mostly using a common training set of 1,677 chemical structures provided by the U.S. EPA, to build a total of 40 categorical......: Individual model scores ranged from 0.69 to 0.85, showing high prediction reliabilities. Out of the 32,464 chemicals, the consensus model predicted 4,001 chemicals (12.3%) as high priority actives and 6,742 potential actives (20.8%) to be considered for further testing. conclusion: This project demonstrated...

Reputational Information and Strategic Collaboration

DEFF Research Database (Denmark)

Andersen, Poul Houman; Bendix, Henrik B.

1998-01-01

What types of information do decision-makers use when deciding on collaboration? What are the role of reputational information in relation to decisions on collaboration......What types of information do decision-makers use when deciding on collaboration? What are the role of reputational information in relation to decisions on collaboration...

System Reliability Engineering

International Nuclear Information System (INIS)

Lim, Tae Jin

2005-02-01

This book tells of reliability engineering, which includes quality and reliability, reliability data, importance of reliability engineering, reliability and measure, the poisson process like goodness of fit test and the poisson arrival model, reliability estimation like exponential distribution, reliability of systems, availability, preventive maintenance such as replacement policies, minimal repair policy, shock models, spares, group maintenance and periodic inspection, analysis of common cause failure, and analysis model of repair effect.

The Role of Collaborative Advantage for Analyzing the Effect of Supply Chain Collaboration on Firm Performance

Directory of Open Access Journals (Sweden)

Huriye Yılmaz

2017-06-01

Full Text Available Collaboration plays a critical role in a globalized, rapidly changing and competitive world, as the resources of an individual company are limited to compete with the challenges of the era. Supply chain collaboration is defined as a partnership process where two or more autonomous firms work closely to plan and execute supply chain operations towards common goals and mutual benefits. Supply chain collaboration results in collaborative advantage, the strategic benefits gained over competitors through supply chain partnering, and these both increase firm performance of the partners. In this research, the effect of supply chain collaboration on firm performance has been investigated by distributing a survey to Turkish companies which have been responded by 150. The role of collaborative advantage in this relation has also been measured. The results of the research suggest that there is a positive correlation between supply chain collaboration and collaborative advantage. The results also prove that supply chain collaboration positively affects firm performance. It is also proven that the mediator role of collaborative advantage on the effect of supply chain collaboration on firm performance is statistically significant.

Reducing unit of a drive in the bottom of a borehole

Energy Technology Data Exchange (ETDEWEB)

Vadetsky, J V; Derkatsch, N D; Krutik, E N; Chudakov, G F; Stroitelev, N P; Natarov, A P; Vasiliev, J S; Andoskin, V N; Ivanov, E I

1979-07-19

A reducing unit for the drive of a drilling tool for deep oil well drilling is proposed, which will guarantee the reduction of the speed of rotation and an increase of the torque for continuous and reliable operation. Overload of the reduction gear boxes to be prevented by suitable means. Bearings are provided which are made as links, which can take axial loads. Technical details are explained. A further device should prevent the effect of torque variation on the operation of the gearbox.

From the Collaborative Environment of the Remote Laboratory NetLab to the Global Collaboration

Directory of Open Access Journals (Sweden)

Jan Machotka

2008-07-01

Full Text Available The remote laboratory (RL can be considered as a modern collaborative learning environment, where students acquire skills required for efficient collaboration and communication on a local and global scale, both today and in the near future. The majority of current existing RLs are not constructed to allow the involved participants to collaborate in real time. This paper describes the collaborative RL NetLab, developed at the University of South Australia (UniSA, which allows up to three onshore and/or offshore students to conduct remote experiments at the same time as a team. This allows the online RL environment to become very similar, if not nearly identical to its real laboratory counterpart. The collaboration in the real laboratory is replaced by the “global” on-line collaboration.

Writing as collaborative inquiry

DEFF Research Database (Denmark)

Frølunde, Lisbeth; Pedersen, Christina Hee; Novak, Martin

2015-01-01

involved in collaborative knowledge production across difference (including age, professional position, life situation, nation). We tell about our experiences with how collaboration can lead toward re-invention of our research practices and methods, as well as our own subjectivities, through involvement......In our presentation we strive to disturb and unravel the romantic discourses of collaboration, dialogue and empowerment in relation to qualitative inquiry. For more than two years we (five Danish and Czech researchers) have been exploring the complex obstructions, difficulties and potentials...... in the not-yet-known. Over the years, we have shared and analyzed personal stories about our collaborative experiences in an on-going reflective learning process. We draw on writing methodologies, including memory-work (Haug, Davies) and collaborative writing such as by Wyatt, Gale, Gannon & Davies. Our...

A reliability simulation language for reliability analysis

International Nuclear Information System (INIS)

Deans, N.D.; Miller, A.J.; Mann, D.P.

1986-01-01

The results of work being undertaken to develop a Reliability Description Language (RDL) which will enable reliability analysts to describe complex reliability problems in a simple, clear and unambiguous way are described. Component and system features can be stated in a formal manner and subsequently used, along with control statements to form a structured program. The program can be compiled and executed on a general-purpose computer or special-purpose simulator. (DG)

A study of operational and testing reliability in software reliability analysis

International Nuclear Information System (INIS)

Yang, B.; Xie, M.

2000-01-01

Software reliability is an important aspect of any complex equipment today. Software reliability is usually estimated based on reliability models such as nonhomogeneous Poisson process (NHPP) models. Software systems are improving in testing phase, while it normally does not change in operational phase. Depending on whether the reliability is to be predicted for testing phase or operation phase, different measure should be used. In this paper, two different reliability concepts, namely, the operational reliability and the testing reliability, are clarified and studied in detail. These concepts have been mixed up or even misused in some existing literature. Using different reliability concept will lead to different reliability values obtained and it will further lead to different reliability-based decisions made. The difference of the estimated reliabilities is studied and the effect on the optimal release time is investigated

A Data Mining Approach to Reveal Representative Collaboration Indicators in Open Collaboration Frameworks

Science.gov (United States)

Anaya, Antonio R.; Boticario, Jesus G.

2009-01-01

Data mining methods are successful in educational environments to discover new knowledge or learner skills or features. Unfortunately, they have not been used in depth with collaboration. We have developed a scalable data mining method, whose objective is to infer information on the collaboration during the collaboration process in a…

Human reliability

International Nuclear Information System (INIS)

Embrey, D.E.

1987-01-01

Concepts and techniques of human reliability have been developed and are used mostly in probabilistic risk assessment. For this, the major application of human reliability assessment has been to identify the human errors which have a significant effect on the overall safety of the system and to quantify the probability of their occurrence. Some of the major issues within human reliability studies are reviewed and it is shown how these are applied to the assessment of human failures in systems. This is done under the following headings; models of human performance used in human reliability assessment, the nature of human error, classification of errors in man-machine systems, practical aspects, human reliability modelling in complex situations, quantification and examination of human reliability, judgement based approaches, holistic techniques and decision analytic approaches. (UK)

Staging Collaborative Innovation Processes

DEFF Research Database (Denmark)

Pedersen, Signe; Clausen, Christian

Organisations are currently challenged by demands for increased collaborative innovation internally as well as with external and new entities - e.g. across the value chain. The authors seek to develop new approaches to managing collaborative innovative processes in the context of open innovation ...... the diverse matters of concern into a coherent product or service concept, and 2) in the same process move these diverse holders of the matters of concern into a translated actor network which carry or support the concept.......Organisations are currently challenged by demands for increased collaborative innovation internally as well as with external and new entities - e.g. across the value chain. The authors seek to develop new approaches to managing collaborative innovative processes in the context of open innovation...... and public private innovation partnerships. Based on a case study of a collaborative design process in a large electronics company the paper points to the key importance of staging and navigation of collaborative innovation process. Staging and navigation is presented as a combined activity: 1) to translate...

An initial reliability and validity study of the Interaction, Communication, and Literacy Skills Audit.

Science.gov (United States)

El-Choueifati, Nisrine; Purcell, Alison; McCabe, Patricia; Heard, Robert; Munro, Natalie

2014-06-01

Early childhood educators (ECEs) have an important role in promoting positive outcomes for children's language and literacy development. This paper reports the development of a new tool, The Interaction Communication and Literacy (ICL) Skills Audit, and pilots its reliability and validity. Intra- and inter-rater reliability was examined by three speech-language pathologists (SLPs). Five skill areas relating to ECE language and literacy practice were rated. The face and content validity of the ICL Skills Audit was examined by expert SLPs (n = 8) and expert ECEs (n = 4) via questionnaire. The overall intra-rater reliability for the ICL Skills Audit was excellent with percentage close agreement (PCA) of 91-94. Inter-rater agreement was PCA 68-80. Expert SLPs and ECEs agreed that the content was comprehensive and practical. Based on this preliminary study, the ICL Skills Audit appears to be a promising tool that can be used by SLPs and ECEs in collaboration to measure the skills of ECEs in the areas of language and literacy support. Future psychometric and outcome research on the revised ICL Skills Audit is warranted.

Power Converter Control Algorithm Design and Simulation for the NREL Next-Generation Drivetrain: July 8, 2013 - January 7, 2016

Energy Technology Data Exchange (ETDEWEB)

Blodgett, Douglas [DNV KEMA Renewables, Inc., San Ramon, CA (United States); Behnke, Michael [DNV KEMA Renewables, Inc., San Ramon, CA (United States); Erdman, William [DNV KEMA Renewables, Inc., San Ramon, CA (United States)

2016-08-01

The National Renewable Energy Laboratory (NREL) and NREL Next-Generation Drivetrain Partners are developing a next-generation drivetrain (NGD) design as part of a Funding Opportunity Announcement award from the U.S. Department of Energy. The proposed NGD includes comprehensive innovations to the gearbox, generator, and power converter that increase the gearbox reliability and drivetrain capacity, while lowering deployment and operation and maintenance costs. A key task within this development effort is the power converter fault control algorithm design and associated computer simulations using an integrated electromechanical model of the drivetrain. The results of this task will be used in generating the embedded control software to be utilized in the power converter during testing of the NGD in the National Wind Technology Center 2.5-MW dynamometer. A list of issues to be addressed with these algorithms was developed by review of the grid interconnection requirements of various North American transmission system operators, and those requirements that presented the greatest impact to the wind turbine drivetrain design were then selected for mitigation via power converter control algorithms.

Estimating Health Condition of the Wind Turbine Drivetrain System

Directory of Open Access Journals (Sweden)

Peng Qian

2017-10-01

Full Text Available Condition Monitoring (CM has been considered as an effective method to enhance the reliability of wind turbines and implement cost-effective maintenance. Thus, adopting an efficient approach for condition monitoring of wind turbines is desirable. This paper presents a data-driven model-based CM approach for wind turbines based on the online sequential extreme learning machine (OS-ELM algorithm. A physical kinetic energy correction model is employed to normalize the temperature change to the value at the rated power output to eliminate the effect of variable speed operation of the turbines. The residual signal, obtained by comparing the predicted values and practical measurements, is processed by the physical correction model and then assessed with a Bonferroni interval method for fault diagnosis. Models have been validated using supervisory control and data acquisition (SCADA data acquired from an operational wind farm, which contains various types of temperature data of the gearbox. The results show that the proposed method can detect more efficiently both the long-term aging characteristics and the short-term faults of the gearbox.

Coupled Thermo-Mechanical and Photo-Chemical Degradation Mechanisms that determine the Reliability and Operational Lifetimes for CPV Technologies

Energy Technology Data Exchange (ETDEWEB)

Dauskardt, Reinhold H. [Stanford Univ., CA (United States)

2017-04-30

This project sought to identify and characterize the coupled intrinsic photo-chemo-mechanical degradation mechanisms that determine the reliability and operational lifetimes for CPV technologies. Over a three year period, we have completed a highly successful program which has developed quantitative metrologies and detailed physics-based degradation models, providing new insight into the fundamental reliability physics necessary for improving materials, creating accelerated testing protocols, and producing more accurate lifetime predictions. The tasks for the program were separated into two focus areas shown in the figure below. Focus Area 1, led by Reinhold Dauskardt and Warren Cai with a primary collaboration with David Miller of NREL, studied the degradation mechanisms present in encapsulant materials. Focus Area 2, led by Reinhold Dauskardt and Ryan Brock with a primary collaboration with James Ermer and Peter Hebert of Spectrolab, studied stress development and degradation within internal CPV device interfaces. Each focus area was productive, leading to several publications, including findings on the degradation of silicone encapsulant under terrestrial UV, a model for photodegradation of silicone encapsulant adhesion, quantification and process tuning of antireflective layers on CPV, and discovery of a thermal cycling degradation mechanism present in metal gridline structures.

Reliability Calculations

DEFF Research Database (Denmark)

Petersen, Kurt Erling

1986-01-01

Risk and reliability analysis is increasingly being used in evaluations of plant safety and plant reliability. The analysis can be performed either during the design process or during the operation time, with the purpose to improve the safety or the reliability. Due to plant complexity and safety...... and availability requirements, sophisticated tools, which are flexible and efficient, are needed. Such tools have been developed in the last 20 years and they have to be continuously refined to meet the growing requirements. Two different areas of application were analysed. In structural reliability probabilistic...... approaches have been introduced in some cases for the calculation of the reliability of structures or components. A new computer program has been developed based upon numerical integration in several variables. In systems reliability Monte Carlo simulation programs are used especially in analysis of very...

Collaboration space division in collaborative product development based on a genetic algorithm

Science.gov (United States)

Qian, Xueming; Ma, Yanqiao; Feng, Huan

2018-02-01

The advance in the global environment, rapidly changing markets, and information technology has created a new stage for design. In such an environment, one strategy for success is the Collaborative Product Development (CPD). Organizing people effectively is the goal of Collaborative Product Development, and it solves the problem with certain foreseeability. The development group activities are influenced not only by the methods and decisions available, but also by correlation among personnel. Grouping the personnel according to their correlation intensity is defined as collaboration space division (CSD). Upon establishment of a correlation matrix (CM) of personnel and an analysis of the collaboration space, the genetic algorithm (GA) and minimum description length (MDL) principle may be used as tools in optimizing collaboration space. The MDL principle is used in setting up an object function, and the GA is used as a methodology. The algorithm encodes spatial information as a chromosome in binary. After repetitious crossover, mutation, selection and multiplication, a robust chromosome is found, which can be decoded into an optimal collaboration space. This new method can calculate the members in sub-spaces and individual groupings within the staff. Furthermore, the intersection of sub-spaces and public persons belonging to all sub-spaces can be determined simultaneously.

SDN Based Collaborative Scheme for Mitigation of DDoS Attacks

Directory of Open Access Journals (Sweden)

Sufian Hameed

2018-02-01

Full Text Available Software Defined Networking (SDN has proved itself to be a backbone in the new network design and is quickly becoming an industry standard. The idea of separation of control plane and data plane is the key concept behind SDN. SDN not only allows us to program and monitor our networks but it also helps in mitigating some key network problems. Distributed denial of service (DDoS attack is among them. In this paper we propose a collaborative DDoS attack mitigation scheme using SDN. We design a secure controller-to-controller (C-to-C protocol that allows SDN-controllers lying in different autonomous systems (AS to securely communicate and transfer attack information with each other. This enables efficient notification along the path of an ongoing attack and effective filtering of traffic near the source of attack, thus saving valuable time and network resources. We also introduced three different deployment approaches i.e., linear, central and mesh in our testbed. Based on the experimental results we demonstrate that our SDN based collaborative scheme is fast and reliable in efficiently mitigating DDoS attacks in real time with very small computational footprints.

NREL-Prime Next-Generation Drivetrain Dynamometer Test Report

Energy Technology Data Exchange (ETDEWEB)

Keller, Jonathan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Erdman, Bill [Cinch, Inc., Moraga, CA (United States); Blodgett, Douglas [DNV KEMA Renewables, Burlington, VT (United States); Halse, Christopher [Romax Technology, Boulder, CO (United States)

2016-08-01

Advances in wind turbine drivetrain technologies are necessary to improve reliability and reduce the cost of energy for land-based and offshore wind turbines. The NREL-Prime Next-Generation Drivetrain team developed a geared, medium-speed drivetrain that is lighter, more reliable and more efficient than existing designs. One of the objectives of Phase II of the project was to complete the detailed design, fabrication, and dynamometer testing of a 750 kilowatt (kW) drivetrain that includes the key gearbox innovations designed by Romax Technology and power converter innovations designed by DNV Kema Renewables. The purpose of this document is to summarize these tests completed in NREL's National Wind Technology Center 2.5 megawatt (MW) dynamometer.

Collaborative teacher learning across foci of collaboration : perceived activities and outcomes

NARCIS (Netherlands)

Doppenberg, J.J.; Brok, den P.J.; Bakx, A.W.E.A.

2012-01-01

This study compared teacher collaboration with differing foci, in terms of various learning activities and learning outcomes. A total of 411 teachers from 49 primary schools participated by completing a questionnaire. Foci of collaboration explained significant differences in the frequency with

Reliability in the utility computing era: Towards reliable Fog computing

DEFF Research Database (Denmark)

Madsen, Henrik; Burtschy, Bernard; Albeanu, G.

2013-01-01

This paper considers current paradigms in computing and outlines the most important aspects concerning their reliability. The Fog computing paradigm as a non-trivial extension of the Cloud is considered and the reliability of the networks of smart devices are discussed. Combining the reliability...... requirements of grid and cloud paradigms with the reliability requirements of networks of sensor and actuators it follows that designing a reliable Fog computing platform is feasible....

Cross-Disciplinary Collaboration and Learning

Directory of Open Access Journals (Sweden)

Deana D. Pennington

2008-12-01

Full Text Available Complex environmental problem solving depends on cross-disciplinary collaboration among scientists. Collaborative research must be preceded by an exploratory phase of collective thinking that creates shared conceptual frameworks. Collective thinking, in a cross-disciplinary setting, depends on the facility with which collaborators are able to learn and understand each others' perspectives. This paper applies three perspectives on learning to the problem of enabling cross-disciplinary collaboration: Maslow's hierarchy of needs, constructivism, and organizational learning. Application of learning frameworks to collaboration provides insights regarding receptive environments for collaboration, and processes that facilitate cross-disciplinary interactions. These environments and interactions need time to develop and require a long phase of idea generation preceding any focused research effort. The findings highlight that collaboration is itself a complex system of people, scientific theory, and tools that must be intentionally managed. Effective management of the system requires leaders who are facilitators and are capable of orchestrating effective environments and interactions.

Dependent systems reliability estimation by structural reliability approach

DEFF Research Database (Denmark)

Kostandyan, Erik; Sørensen, John Dalsgaard

2014-01-01

Estimation of system reliability by classical system reliability methods generally assumes that the components are statistically independent, thus limiting its applicability in many practical situations. A method is proposed for estimation of the system reliability with dependent components, where...... the leading failure mechanism(s) is described by physics of failure model(s). The proposed method is based on structural reliability techniques and accounts for both statistical and failure effect correlations. It is assumed that failure of any component is due to increasing damage (fatigue phenomena...... identification. Application of the proposed method can be found in many real world systems....

Collaborative interactive visualization: exploratory concept

Science.gov (United States)

Mokhtari, Marielle; Lavigne, Valérie; Drolet, Frédéric

2015-05-01

Dealing with an ever increasing amount of data is a challenge that military intelligence analysts or team of analysts face day to day. Increased individual and collective comprehension goes through collaboration between people. Better is the collaboration, better will be the comprehension. Nowadays, various technologies support and enhance collaboration by allowing people to connect and collaborate in settings as varied as across mobile devices, over networked computers, display walls, tabletop surfaces, to name just a few. A powerful collaboration system includes traditional and multimodal visualization features to achieve effective human communication. Interactive visualization strengthens collaboration because this approach is conducive to incrementally building a mental assessment of the data meaning. The purpose of this paper is to present an overview of the envisioned collaboration architecture and the interactive visualization concepts underlying the Sensemaking Support System prototype developed to support analysts in the context of the Joint Intelligence Collection and Analysis Capability project at DRDC Valcartier. It presents the current version of the architecture, discusses future capabilities to help analyst(s) in the accomplishment of their tasks and finally recommends collaboration and visualization technologies allowing to go a step further both as individual and as a team.

Students experiences with collaborative learning in asynchronous computer-supported collaborative learning environments.

NARCIS (Netherlands)

Dewiyanti, Silvia; Brand-Gruwel, Saskia; Jochems, Wim; Broers, Nick

2008-01-01

Dewiyanti, S., Brand-Gruwel, S., Jochems, W., & Broers, N. (2007). Students experiences with collaborative learning in asynchronous computer-supported collaborative learning environments. Computers in Human Behavior, 23, 496-514.

Reliable implementation of evidence: a qualitative study of antenatal corticosteroid administration in Ohio hospitals.

Science.gov (United States)

Kaplan, Heather C; Sherman, Susan N; Cleveland, Charlena; Goldenhar, Linda M; Lannon, Carole M; Bailit, Jennifer L

2016-03-01

Antenatal corticosteroids (ANCS) reduce complications of preterm birth; however, not all eligible women receive them. Many hospitals and providers do not have the right processes and conditions to enable ANCS administration with high reliability. The objective of this study was to understand conditions that enable delivery of ANCS with high reliability among hospitals participating in an Ohio Perinatal Quality Collaborative (OPQC) ANCS project. We conducted focus groups and semistructured interviews with members of the OPQC project team (n=27) and other care providers (n=70) using a purposeful sample of 6 sites involved in the OPQC ANCS project. Participants including nurses (n=57), attending obstetricians (n=17), physician trainees (n=21) and certified nurse midwives (n=2) were asked to reflect on their experiences and to identify factors contributing to optimal use of ANCS. Focus groups and interviews were transcribed verbatim and were analysed by a multidisciplinary team using an iterative approach that combined inductive and deductive methods to identify and categorise themes. Six major themes supporting reliable implementation of ANCS at these hospitals emerged including: (1) presence of a high reliability culture, (2) processes that emphasise high reliability, (3) timely and efficient administration process, (4) multiple disciplines are involved, (5) evidence of benefit supports ANCS use and (6) benefit is recognised at all levels of the care team. Our findings identify the key processes and supports needed to ensure delivery of ASCS with high reliability and are reinforced by implementation and reliability science. They are useful for foundation of the successful implementation of other evidence-based practices at high levels of reliability. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Analyzing the reliability of shuffle-exchange networks using reliability block diagrams

International Nuclear Information System (INIS)

Bistouni, Fathollah; Jahanshahi, Mohsen

2014-01-01

Supercomputers and multi-processor systems are comprised of thousands of processors that need to communicate in an efficient way. One reasonable solution would be the utilization of multistage interconnection networks (MINs), where the challenge is to analyze the reliability of such networks. One of the methods to increase the reliability and fault-tolerance of the MINs is use of various switching stages. Therefore, recently, the reliability of one of the most common MINs namely shuffle-exchange network (SEN) has been evaluated through the investigation on the impact of increasing the number of switching stage. Also, it is concluded that the reliability of SEN with one additional stage (SEN+) is better than SEN or SEN with two additional stages (SEN+2), even so, the reliability of SEN is better compared to SEN with two additional stages (SEN+2). Here we re-evaluate the reliability of these networks where the results of the terminal, broadcast, and network reliability analysis demonstrate that SEN+ and SEN+2 continuously outperform SEN and are very alike in terms of reliability. - Highlights: • The impact of increasing the number of stages on reliability of MINs is investigated. • The RBD method as an accurate method is used for the reliability analysis of MINs. • Complex series–parallel RBDs are used to determine the reliability of the MINs. • All measures of the reliability (i.e. terminal, broadcast, and network reliability) are analyzed. • All reliability equations will be calculated for different size N×N

Perceptual Factors Affecting the Tendency to Collaboration in SMEs: Perceived Importance of Collaboration Modes and Partners

Directory of Open Access Journals (Sweden)

Heeyong Noh

2015-10-01

Full Text Available This research aims to explore key factors of SMEs’ external collaboration and identifies the perceived factors affecting propensity for collaboration. Particularly, we focus on two factors – internal strategic activities geared towards open innovation and external collaboration partners, both of which are essential to establishing an external collaboration. We conducted a survey of Korean SMEs regarding their collaboration project experiences, and used logistic regression analysis to analyze the survey data. The research findings are expected to help understanding the complex open innovation mechanism in SMEs and to have meaningful implications for the development of their collaboration model.

Opposing incentives for collaboration

DEFF Research Database (Denmark)

Dorch, Bertil F.; Wien, Charlotte; Larsen, Asger Væring

, and gives a bonus for publications done through inter-institutionary collaboration. Credits given to universities are fractionalized between the participating universities. So far credits are not assigned to the individual authors but only to their institutions. However, it turns out that research...... collaboration is associated with a higher number of citations than single authorship which may present the author with two opposing incentives for research collaboration....

Professional Learning and Collaboration

OpenAIRE

Greer, Janet Agnes

2012-01-01

The American education system must utilize collaboration to meet the challenges and demands our culture poses for schools. Deeply rooted processes and structures favor teaching and learning in isolation and hinder the shift to a more collaborative paradigm. Professional learning communities (PLCs) support continuous teacher learning, improved efficacy, and program implementation. The PLC provides the framework for the development and enhancement of teacher collaboration and teacher collaborat...

Collaborative engagement experiment

Science.gov (United States)

Mullens, Katherine; Troyer, Bradley; Wade, Robert; Skibba, Brian; Dunn, Michael

2006-05-01

Unmanned ground and air systems operating in collaboration have the potential to provide future Joint Forces a significant capability for operations in complex terrain. Collaborative Engagement Experiment (CEE) is a consolidation of separate Air Force, Army and Navy collaborative efforts within the Joint Robotics Program (JRP) to provide a picture of the future of unmanned warfare. The Air Force Research Laboratory (AFRL), Material and Manufacturing Directorate, Aerospace Expeditionary Force Division, Force Protection Branch (AFRL/MLQF), The Army Aviation and Missile Research, Development and Engineering Center (AMRDEC) Joint Technology Center (JTC)/Systems Integration Laboratory (SIL), and the Space and Naval Warfare Systems Center - San Diego (SSC San Diego) are conducting technical research and proof of principle experiments for an envisioned operational concept for extended range, three dimensional, collaborative operations between unmanned systems, with enhanced situational awareness for lethal operations in complex terrain. This paper describes the work by these organizations to date and outlines some of the plans for future work.

Strategies for Building a Reliable, Diverse Pipeline of Earth Data Scientists

Science.gov (United States)

Fowler, R.; Robinson, E.

2015-12-01

The grand challenges facing the geosciences are increasingly data-driven and require large-scale collaboration. Today's geoscience community is primarily self-taught or peer-taught as neither data science nor collaborative skills are traditionally part of the geoscience curriculum. This is not a sustainable model. By increasing understanding of the role of data science and collaboration in the geosciences, and Earth and space science informatics, an increased number of students pursuing STEM degrees may choose careers in these fields. Efforts to build a reliable pipeline of future Earth data scientists must incorporate the following: (1) improved communication: covering not only what data science is, but what a data scientist working in the geosciences does and the impact their work has; (2) effective identification and promotion of the skills and knowledge needed, including possible academic and career paths, the availability and types of jobs in the geosciences, and how to develop the necessary skills for these careers; (3) the employment of recruitment and engagement strategies that result in a diverse data science workforce, especially the recruitment and inclusion of underrepresented minority students; and (4) changing organizational cultures to better retain and advance women and other minority groups in data science. In this presentation we'll discuss strategies to increase the number of women and underrepresented minority students pursuing careers in data science, with an emphasis on effective strategies for recruiting and mentoring these groups, as well as challenges faced and lessons learned.

Mobile Collaborative Informal Learning Design: Study of collaborative effectiveness using Activity Theory

Directory of Open Access Journals (Sweden)

Hasnain Zafar Baloch

2012-07-01

Full Text Available Smart Mobile Devices (SMD are there for many years but using them as learning tools started to emerge as new research area. The trend to merge collaborative learning methodology by using mobile devices in informal context is important for implementation of Learner Centric Learning (LCL. Survey and numerous studies show that more than 95% of students in colleges are users of these smart mobile devices in developed world. Developing counties are also catching up and we can see this percentage is almost same in university level in these countries. Students are using SMDs for learning in some form. Higher education Institutions also try to embark their E-learning to Mobile learning (ML. The aim of this paper is to do propose operational framework for designing Mobile Collaborative Informal learning activities using SMDs. Show results of experimental and case study done to study the Mobile Collaborative Informal learning using Activity Theory (AT. Core Components of framework are Mobile Learning Activities/Objects, Wireless/Mobile Smart devices, Collaborative knowledge and Collaborative learning. The research mention here is its infancy stage.

Seven Affordances of Computer-Supported Collaborative Learning: How to Support Collaborative Learning? How Can Technologies Help?

Science.gov (United States)

Jeong, Heisawn; Hmelo-Silver, Cindy E.

2016-01-01

This article proposes 7 core affordances of technology for collaborative learning based on theories of collaborative learning and CSCL (Computer-Supported Collaborative Learning) practices. Technology affords learner opportunities to (1) engage in a joint task, (2) communicate, (3) share resources, (4) engage in productive collaborative learning…

Process and data fragmentation-oriented enterprise network integration with collaboration modelling and collaboration agents

Science.gov (United States)

Li, Qing; Wang, Ze-yuan; Cao, Zhi-chao; Du, Rui-yang; Luo, Hao

2015-08-01

With the process of globalisation and the development of management models and information technology, enterprise cooperation and collaboration has developed from intra-enterprise integration, outsourcing and inter-enterprise integration, and supply chain management, to virtual enterprises and enterprise networks. Some midfielder enterprises begin to serve for different supply chains. Therefore, they combine related supply chains into a complex enterprise network. The main challenges for enterprise network's integration and collaboration are business process and data fragmentation beyond organisational boundaries. This paper reviews the requirements of enterprise network's integration and collaboration, as well as the development of new information technologies. Based on service-oriented architecture (SOA), collaboration modelling and collaboration agents are introduced to solve problems of collaborative management for service convergence under the condition of process and data fragmentation. A model-driven methodology is developed to design and deploy the integrating framework. An industrial experiment is designed and implemented to illustrate the usage of developed technologies in this paper.

A Mechanistic Reliability Assessment of RVACS and Metal Fuel Inherent Reactivity Feedbacks

Energy Technology Data Exchange (ETDEWEB)

Grabaskas, David; Brunett, Acacia J.; Passerini, Stefano; Grelle, Austin

2017-09-24

GE Hitachi Nuclear Energy (GEH) and Argonne National Laboratory (Argonne) participated in a two year collaboration to modernize and update the probabilistic risk assessment (PRA) for the PRISM sodium fast reactor. At a high level, the primary outcome of the project was the development of a next-generation PRA that is intended to enable risk-informed prioritization of safety- and reliability-focused research and development. A central Argonne task during this project was a reliability assessment of passive safety systems, which included the Reactor Vessel Auxiliary Cooling System (RVACS) and the inherent reactivity feedbacks of the metal fuel core. Both systems were examined utilizing a methodology derived from the Reliability Method for Passive Safety Functions (RMPS), with an emphasis on developing success criteria based on mechanistic system modeling while also maintaining consistency with the Fuel Damage Categories (FDCs) of the mechanistic source term assessment. This paper provides an overview of the reliability analyses of both systems, including highlights of the FMEAs, the construction of best-estimate models, uncertain parameter screening and propagation, and the quantification of system failure probability. In particular, special focus is given to the methodologies to perform the analysis of uncertainty propagation and the determination of the likelihood of violating FDC limits. Additionally, important lessons learned are also reviewed, such as optimal sampling methodologies for the discovery of low likelihood failure events and strategies for the combined treatment of aleatory and epistemic uncertainties.

Reliability data banks

International Nuclear Information System (INIS)

Cannon, A.G.; Bendell, A.

1991-01-01

Following an introductory chapter on Reliability, what is it, why it is needed, how it is achieved and measured, the principles of reliability data bases and analysis methodologies are the subject of the next two chapters. Achievements due to the development of data banks are mentioned for different industries in the next chapter, FACTS, a comprehensive information system for industrial safety and reliability data collection in process plants are covered next. CREDO, the Central Reliability Data Organization is described in the next chapter and is indexed separately, as is the chapter on DANTE, the fabrication reliability Data analysis system. Reliability data banks at Electricite de France and IAEA's experience in compiling a generic component reliability data base are also separately indexed. The European reliability data system, ERDS, and the development of a large data bank come next. The last three chapters look at 'Reliability data banks, - friend foe or a waste of time'? and future developments. (UK)

An Introduction To Reliability

International Nuclear Information System (INIS)

Park, Kyoung Su

1993-08-01

This book introduces reliability with definition of reliability, requirement of reliability, system of life cycle and reliability, reliability and failure rate such as summary, reliability characteristic, chance failure, failure rate which changes over time, failure mode, replacement, reliability in engineering design, reliability test over assumption of failure rate, and drawing of reliability data, prediction of system reliability, conservation of system, failure such as summary and failure relay and analysis of system safety.

Collaborative entrepreneurship: On the Influence of Internal and External Collaboration on Corporate Entrepreneurial Innovation

DEFF Research Database (Denmark)

Lassen, Astrid Heidemann; Timenes Laugen, Bjørge; Middel, Rick

2008-01-01

The present paper empirically tests the effect which internal/external collaboration has on innovation height and identifies characteristics of collaboration patterns leading to entrepreneurial innovation in particular. Doing so adds to the understanding of how corporate entrepreneurship best...... unfolds as interfirm activity, which here is termed collaborative entrepreneurship, and provides details on the particular patterns of Open Innovation. The empirical analysis is based on a data set with responses from 512 Danish engineers. The analysis finds that external collaboration has significantly...... different effects on innovation height depending on the type of partners involved, and furthermore suggests that the development of entrepreneurial innovation is not only dependent on high external involvement, but also on involvement and collaboration among internal functional departments and people....

Adaptation in Collaborative Governance Regimes

Science.gov (United States)

Emerson, Kirk; Gerlak, Andrea K.

2014-10-01

Adaptation and the adaptive capacity of human and environmental systems have been of central concern to natural and social science scholars, many of whom characterize and promote the need for collaborative cross-boundary systems that are seen as flexible and adaptive by definition. Researchers who study collaborative governance systems in the public administration, planning and policy literature have paid less attention to adaptive capacity specifically and institutional adaptation in general. This paper bridges the two literatures and finds four common dimensions of capacity, including structural arrangements, leadership, knowledge and learning, and resources. In this paper, we focus on institutional adaptation in the context of collaborative governance regimes and try to clarify and distinguish collaborative capacity from adaptive capacity and their contributions to adaptive action. We posit further that collaborative capacities generate associated adaptive capacities thereby enabling institutional adaptation within collaborative governance regimes. We develop these distinctions and linkages between collaborative and adaptive capacities with the help of an illustrative case study in watershed management within the National Estuary Program.

Comprehensive multiplatform collaboration

Science.gov (United States)

Singh, Kundan; Wu, Xiaotao; Lennox, Jonathan; Schulzrinne, Henning G.

2003-12-01

We describe the architecture and implementation of our comprehensive multi-platform collaboration framework known as Columbia InterNet Extensible Multimedia Architecture (CINEMA). It provides a distributed architecture for collaboration using synchronous communications like multimedia conferencing, instant messaging, shared web-browsing, and asynchronous communications like discussion forums, shared files, voice and video mails. It allows seamless integration with various communication means like telephones, IP phones, web and electronic mail. In addition, it provides value-added services such as call handling based on location information and presence status. The paper discusses the media services needed for collaborative environment, the components provided by CINEMA and the interaction among those components.

Collaborative Video Sketching

DEFF Research Database (Denmark)

Henningsen, Birgitte; Gundersen, Peter Bukovica; Hautopp, Heidi

2017-01-01

This paper introduces to what we define as a collaborative video sketching process. This process links various sketching techniques with digital storytelling approaches and creative reflection processes in video productions. Traditionally, sketching has been used by designers across various...... findings: 1) They are based on a collaborative approach. 2) The sketches act as a mean to externalizing hypotheses and assumptions among the participants. Based on our analysis we present an overview of factors involved in collaborative video sketching and shows how the factors relate to steps, where...... the participants: shape, record, review and edit their work, leading the participants to new insights about their work....

Collaborations in fusion research

International Nuclear Information System (INIS)

Barnes, D.; Davis, S.; Roney, P.

1995-01-01

This paper reviews current experimental collaborative efforts in the fusion community and extrapolates to operational scenarios for the Tokamak Physics Experiment (TPX) and the International Thermonuclear Experimental Reactor (ITER). Current requirements, available technologies and tools, and problems, issues and concerns are discussed. This paper specifically focuses on the issues that apply to experimental operational collaborations. Special requirements for other types of collaborations, such as theoretical or design and construction efforts, will not be addressed. Our current collaborative efforts have been highly successful, even though the tools in use will be viewed as primitive by tomorrow's standards. An overview of the tools and technologies in today's collaborations can be found in the first section of this paper. The next generation of fusion devices will not be primarily institutionally based, but will be national (TPX) and international (ITER) in funding, management, operation and in ownership of scientific results. The TPX will present the initial challenge of real-time remotely distributed experimental data analysis for a steady state device. The ITER will present new challenges with the possibility of several remote control rooms all participating in the real-time operation of the experimental device. A view to the future of remote collaborations is provided in the second section of this paper

Realities of Supply Chain Collaboration

NARCIS (Netherlands)

Kampstra, R.P.; Ashayeri, J.; Gattorna, J.

2006-01-01

Successful supply chain collaboration (SCC) practices are rather exceptional, yet collaboration is believed to be the single most pressing need in supply chain management.In this paper we discuss the realities of SCC, present prerequisites for the collaboration process, indicate where the process

Reliability calculations

International Nuclear Information System (INIS)

Petersen, K.E.

1986-03-01

Risk and reliability analysis is increasingly being used in evaluations of plant safety and plant reliability. The analysis can be performed either during the design process or during the operation time, with the purpose to improve the safety or the reliability. Due to plant complexity and safety and availability requirements, sophisticated tools, which are flexible and efficient, are needed. Such tools have been developed in the last 20 years and they have to be continuously refined to meet the growing requirements. Two different areas of application were analysed. In structural reliability probabilistic approaches have been introduced in some cases for the calculation of the reliability of structures or components. A new computer program has been developed based upon numerical integration in several variables. In systems reliability Monte Carlo simulation programs are used especially in analysis of very complex systems. In order to increase the applicability of the programs variance reduction techniques can be applied to speed up the calculation process. Variance reduction techniques have been studied and procedures for implementation of importance sampling are suggested. (author)

Towards a Model of Collaborative Intention

DEFF Research Database (Denmark)

Razmerita, Liana; Kirchner, Kathrin; Hockerts, Kai

2018-01-01

outcome expectancy and communal support expectancy. Additionally, we reveal that collaborative outcome expectancy is predicated on individuals’ belief about his/her ability to collaborate whereas communal support expectancy is impacted by the individual’s perception of communal influence.......Disentangling factors that affect one’s intention to collaborate is an important endeavor for management education, especially for globally dispersed groups of students. Drawing on a synthesis of four theories, we advance a model of collaboration intentions that embodies both individual...... and communal level drivers of individuals’ intention to participate in virtual collaboration. The model is validated based on data collected from 2,517 participants in a Massive Online Open Course (MOOC). Results demonstrate that attitudes towards virtual collaboration are predicted by both collaborative...

Deriving Process-Driven Collaborative Editing Pattern from Collaborative Learning Flow Patterns

Science.gov (United States)

Marjanovic, Olivera; Skaf-Molli, Hala; Molli, Pascal; Godart, Claude

2007-01-01

Collaborative Learning Flow Patterns (CLFPs) have recently emerged as a new method to formulate best practices in structuring the flow of activities within various collaborative learning scenarios. The term "learning flow" is used to describe coordination and sequencing of learning tasks. This paper adopts the existing concept of CLFP and argues…

International collaborations through the internet

DEFF Research Database (Denmark)

Olson, Gary M.; David, Paul A.; Eksteen, Johan

2007-01-01

The past decade has seen remarkable advances in the availability of tools to support scientific collaboration at a distance. This is especially good news for international collaborations, where in the past constraints on collocation and travel have made such collaborations a major challenge. The ...

The REPAS approach to the evaluation of passive safety systems reliability

International Nuclear Information System (INIS)

Bianchi, F.; Burgazzi, L.; D'Auria, F.; Ricotti, M.E.

2002-01-01

Scope of this research, carried out by ENEA in collaboration with University of Pisa and Polytechnic of Milano since 1999, is the identification of a methodology allowing the evaluation of the reliability of passive systems as a whole, in a more physical and phenomenal way. The paper describe the study, named REPAS (Reliability Evaluation of Passive Safety systems), carried out by the partners and finalised to the development and validation of such a procedure. The strategy of engagement moves from the consideration that a passive system should be theoretically more reliable than an active one. In fact it does not need any external input or energy to operate and it relies only upon natural physical laws (e.g. gravity, natural circulation, internally stored energy, etc.) and/or 'intelligent' use of the energy inherently available in the system (e.g. chemical reaction, decay heat, etc.). Nevertheless the passive system may fail its mission not only as a consequence of classical mechanical failure of components, but also for deviation from the expected behaviour, due to physical phenomena mainly related to thermal-hydraulics or due to different boundary and initial conditions. The main sources of physical failure are identified and a probability of occurrence is assigned. The reliability analysis is performed on a passive system which operates in two-phase, natural circulation. The selected system is a loop including a heat source and a heat sink where the condensation occurs. The system behaviour under different configurations has been simulated via best-estimate code (Relap5 mod3.2). The results are shown and can be treated in such a way to give qualitative and quantitative information on the system reliability. Main routes of development of the methodology are also depicted. The analysis of the results shows that the procedure is suitable to evaluate the performance of a passive system on a probabilistic / deterministic basis. Important information can also be

Collaborative Modular Pumped Hydro Energy Storage Design Study

Energy Technology Data Exchange (ETDEWEB)

Bibeault, Mark Leonide [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Roybal, Adam [Jemez Mountain Electric Cooperative, Inc., Hernandez, NM (United States); Bailey, Jr., Richard J. [Northern New Mexico College, Espanola, NM (United States)

2017-09-29

In May of 2017, Los Alamos National Laboratory (LANL) through the Applied Engineering Technology Division, Jemez Mountain Electric Cooperative Inc. (JMEC), and Northern New Mexico College (NNMC) agreed to enter into a small, joint, non-binding Modular Pumped Hydro (MPH) design study related to grid level energy storage to begin a process of collaboration. Los Alamos National Laboratory's mission is to solve national security challenges through scientific excellence. The mission of Northern New Mexico College is to ensure student success by providing access to affordable, community-based learning opportunities that meet the educational, cultural, and economic needs of the region. Jemez Mountain Electric Cooperative Inc. is the largest electric co-op in the State of New Mexico providing affordable and reliable electricity to customers in the five counties of Rio Arriba, Santa Fe, San Juan, McKinley and Sandoval.

Collaborative Communities of Firms

DEFF Research Database (Denmark)

2011-01-01

and developing strategic initiatives that aid the community as a whole. We discuss the facilitator role of the shared services provider, contrasting it with the coordinator role found in other multi-firm organizations, and we show how shared services providers function by describing three examples...... is an organizational model called the collaborative community of firms. This chapter addresses an important organizational role in a collaborative community, that of the shared services provider. The shared services provider acts as a facilitator in the community, helping member firms collaborate with one another...... of collaborative communities of firms from different sectors: the U.S.-based Blade.org and two Denmark-based communities, the Kalundborg Industrial Symbiosis and MG50. Implications for the theory and practice of organization design are discussed....

Collaboration in scientific practice

DEFF Research Database (Denmark)

Wagenknecht, Susann

2014-01-01

This monograph investigates the collaborative creation of scientific knowledge in research groups. To do so, I combine philosophical analysis with a first-hand comparative case study of two research groups in experimental science. Qualitative data are gained through observation and interviews......, and I combine empirical insights with existing approaches to knowledge creation in philosophy of science and social epistemology. On the basis of my empirically-grounded analysis I make several conceptual contributions. I study scientific collaboration as the interaction of scientists within research...... to their publication. Specifically, I suggest epistemic difference and the porosity of social structure as two conceptual leitmotifs in the study of group collaboration. With epistemic difference, I emphasize the value of socio-cognitive heterogeneity in group collaboration. With porosity, I underline the fact...

Drivers of Collaborative Advantage

DEFF Research Database (Denmark)

Weihe, Gudrid

processes and behavioural dimensions is practically non-existent. This article tries to remedy the current gap in the literature by reviewing research findings on interfirm collaboration (alliances). On that basis a conceptual framework for analyzing partnership processes is developed. Finally......, the antecedents of collaborative advantage are theoretically examined, and the organizational competences contributing to collaborative success are identified. The conclusion is that operational processes and social dynamics are vital drivers of collaborative advantage. Another significant conclusion...... is that public management research can benefit from drawing upon existing alliance research. Alliance scholars have during the past couple of decades accumulated an impressive amount of knowledge on different aspects of inter-firm cooperation, and therefore the learning potential for public management scholars...

Assessment of (Computer-Supported) Collaborative Learning

Science.gov (United States)

Strijbos, J. -W.

2011-01-01

Within the (Computer-Supported) Collaborative Learning (CS)CL research community, there has been an extensive dialogue on theories and perspectives on learning from collaboration, approaches to scaffold (script) the collaborative process, and most recently research methodology. In contrast, the issue of assessment of collaborative learning has…

Validation of Metrics for Collaborative Systems

OpenAIRE

Ion IVAN; Cristian CIUREA

2008-01-01

This paper describe the new concepts of collaborative systems metrics validation. The paper define the quality characteristics of collaborative systems. There are proposed a metric to estimate the quality level of collaborative systems. There are performed measurements of collaborative systems quality using a specially designed software.

COLLABORATION BOARD (CB55)

CERN Multimedia

B. Cousins

Open Access Publication Policy ATLAS had recently issued a short statement in support of open access publishing. The mood of the discussions in the December CMS Collaboration Board had appeared to be in favour and so it was being proposed that CMS issue the same statement as that made by ATLAS (the statement is attached to the agenda of this meeting). The Collaboration Board agreed. Election of the Chair of the Collaboration Board Following the agreement to shorten the terms of both the Spokesperson and the Collaboration Board Chair, and to introduce a longer overlap period between the election and the start of the term, the election for the next Collaboration Board Chair was due in December 2007. If the old standard schedule specified in the Constitution were adapted to this date, then the Board should be informed at the present meeting that the election was being prepared. However, it was felt that the experience of the previous year's election of the Spokesperson had shown that it would be desirable to...

Interactive reliability assessment using an integrated reliability data bank

International Nuclear Information System (INIS)

Allan, R.N.; Whitehead, A.M.

1986-01-01

The logical structure, techniques and practical application of a computer-aided technique based on a microcomputer using floppy disc Random Access Files is described. This interactive computational technique is efficient if the reliability prediction program is coupled directly to a relevant source of data to create an integrated reliability assessment/reliability data bank system. (DG)

Framework for Students’ Online Collaborative Writing

DEFF Research Database (Denmark)

Sørensen, Birgitte Holm; Levinsen, Karin Tweddell; Holm, Madeleine Rygner

2016-01-01

The paper focuses on collaborative writing in Google Docs and presents a framework for how students can develop methods for collaborations that include human and non-human actors. The paper is based on the large-scale research and development project Students’ Digital Production and Students...... shows that teachers do not introduce or refer the students to online collaborative strategies, roles or communications. The students’ online collaborative writing is entirely within the students’ domain. On this basis, the paper focuses on how teachers’ awareness and articulation of the students’ online...... collaborative writing within a framework can qualify students´ methods to collaborate online with the intention to improve their learning results. In relation to this, the paper explores how digital technologies may act as co-participants in collaboration, production and reflection. Moreover, the framework...

Validation of Metrics for Collaborative Systems

Directory of Open Access Journals (Sweden)

Ion IVAN

2008-01-01

Full Text Available This paper describe the new concepts of collaborative systems metrics validation. The paper define the quality characteristics of collaborative systems. There are proposed a metric to estimate the quality level of collaborative systems. There are performed measurements of collaborative systems quality using a specially designed software.

Development and initial validation of the Pharmacist Frequency of Interprofessional Collaboration Instrument (FICI-P) in primary care.

Science.gov (United States)

Van, Connie; Costa, Daniel; Mitchell, Bernadette; Abbott, Penny; Krass, Ines

2012-01-01

Existing validated measures of pharmacist-physician collaboration focus on measuring attitudes toward collaboration and do not measure frequency of collaborative interactions. To develop and validate an instrument to measure the frequency of collaboration between pharmacists and general practitioners (GPs) from the pharmacist's perspective. An 11-item Pharmacist Frequency of Interprofessional Collaboration Instrument (FICI-P) was developed and administered to 586 pharmacists in 8 divisions of general practice in New South Wales, Australia. The initial items were informed by a review of the literature in addition to interviews of pharmacists and GPs. Items were subjected to principal component and Rasch analyses to determine each item's and the overall measure's psychometric properties and for any needed refinements. Two hundred and twenty four (38%) of pharmacist surveys were completed and returned. Principal component analysis suggested removal of 1 item for a final 1-factor solution. The refined 10-item FICI-P demonstrated internal consistency reliability at Cronbach's alpha=0.90. After collapsing the original 5-point response scale to a 4-point response scale, the refined FICI-P demonstrated fit to the Rasch model. Criterion validity of the FICI-P was supported by the correlation of FICI-P scores with scores on a previously validated Physician-Pharmacist Collaboration Instrument. Validity was also supported by predicted differences in FICI-P scores between subgroups of respondents stratified on age, colocation with GPs, and interactions during the intern-training period. The refined 10-item FICI-P was shown to have good internal consistency, criterion validity, and fit to the Rasch model. The creation of such a tool may allow for the measure of impact in the evaluation of interventions designed to improve interprofessional collaboration between GPs and pharmacists. Copyright © 2012 Elsevier Inc. All rights reserved.

Use of an Interculturally Enriched Collaboration Script in Computer-Supported Collaborative Learning in Higher Education

Science.gov (United States)

Popov, Vitaliy; Biemans, Harm J. A.; Kuznetsov, Andrei N.; Mulder, Martin

2014-01-01

In this exploratory study, the authors introduced an interculturally enriched collaboration script (IECS) for working in culturally diverse groups within a computer-supported collaborative learning (CSCL) environment and then assessed student online collaborative behaviour, learning performance and experiences. The question was if and how these…

A Metrics Approach for Collaborative Systems

Directory of Open Access Journals (Sweden)

Cristian CIUREA

2009-01-01

Full Text Available This article presents different types of collaborative systems, their structure and classification. This paper defines the concept of virtual campus as a collaborative system. It builds architecture for virtual campus oriented on collaborative training processes. It analyses the quality characteristics of collaborative systems and propose techniques for metrics construction and validation in order to evaluate them. The article analyzes different ways to increase the efficiency and the performance level in collaborative banking systems.

Security for ICT collaboration tools

NARCIS (Netherlands)

Broenink, E.G.; Kleinhuis, G.; Fransen, F.

2010-01-01

In order for collaboration tools to be productive in an operational setting, an information base that is shared across the collaborating parties is needed. Therefore, a lot of research is done for tooling to create such a common information base in a collaboration tool. However, security is often

Security for ICT collaboration tools

NARCIS (Netherlands)

Broenink, E.G.; Kleinhuis, G.; Fransen, F.

2011-01-01

In order for collaboration tools to be productive in an operational setting, an information base that is shared across the collaborating parties is needed. Therefore, a lot of research is done for tooling to create such a common information base in a collaboration tool. However, security is often

Breakdowns in collaborative information seeking

DEFF Research Database (Denmark)

Hertzum, Morten

2010-01-01

Collaborative information seeking is integral to many professional activities. In hospital work, the medication process encompasses continual seeking for information and collaborative grounding of information. This study investigates breakdowns in collaborative information seeking through analyses...... of the use of the electronic medication record adopted in a Danish healthcare region and of the reports of five years of medication incidents at Danish hospitals. The results show that breakdowns in collaborative information seeking is a major source of medication incidents, that most of these breakdowns...... are breakdowns in collaborative grounding rather than information seeking, that the medication incidents mainly concern breakdowns in the use of records as opposed to oral communication, that the breakdowns span multiple degrees of separation between clinicians, and that the electronic medication record has...

76 FR 23222 - Electric Reliability Organization Interpretation of Transmission Operations Reliability

Science.gov (United States)

2011-04-26

....3d 1342 (DC Cir. 2009). \\5\\ Mandatory Reliability Standards for the Bulk-Power System, Order No. 693... Reliability Standards for the Bulk-Power System. Action: FERC-725A. OMB Control No.: 1902-0244. Respondents...] Electric Reliability Organization Interpretation of Transmission Operations Reliability AGENCY: Federal...

Reliability of classification for post-traumatic ankle osteoarthritis.

Science.gov (United States)

Claessen, Femke M A P; Meijer, Diederik T; van den Bekerom, Michel P J; Gevers Deynoot, Barend D J; Mallee, Wouter H; Doornberg, Job N; van Dijk, C Niek

2016-04-01

The purpose of this study was to identify the most reliable classification system for clinical outcome studies to categorize post-traumatic-fracture-osteoarthritis. A total of 118 orthopaedic surgeons and residents-gathered in the Ankle Platform Study Collaborative Science of Variation Group-evaluated 128 anteroposterior and lateral radiographs of patients after a bi- or trimalleolar ankle fracture on a Web-based platform in order to rate post-traumatic osteoarthritis according to the classification systems coined by (1) van Dijk, (2) Kellgren, and (3) Takakura. Reliability was evaluated with the use of the Siegel and Castellan's multirater kappa measure. Differences between classification systems were compared using the two-sample Z-test. Interobserver agreement of surgeons who participated in the survey was fair for the van Dijk osteoarthritis scale (k = 0.24), and poor for the Takakura (k = 0.19) and the Kellgren systems (k = 0.18) according to the categorical rating of Landis and Koch. This difference in one categorical rating was found to be significant (p osteoarthritis scale, and poor interobserver agreement for the Takakura and Kellgren osteoarthritis classification systems. Because of the low interobserver agreement for the van Dijk, Kellgren, and Takakura classification systems, those systems cannot be used for clinical decision-making. Development of diagnostic criteria on basis of consecutive patients, Level II.

An Analysis of Collaborative Problem-Solving Activities Mediated by Individual-Based and Collaborative Computer Simulations

Science.gov (United States)

Chang, C.-J.; Chang, M.-H.; Liu, C.-C.; Chiu, B.-C.; Fan Chiang, S.-H.; Wen, C.-T.; Hwang, F.-K.; Chao, P.-Y.; Chen, Y.-L.; Chai, C.-S.

2017-01-01

Researchers have indicated that the collaborative problem-solving space afforded by the collaborative systems significantly impact the problem-solving process. However, recent investigations into collaborative simulations, which allow a group of students to jointly manipulate a problem in a shared problem space, have yielded divergent results…

Understanding Nomadic Collaborative Learning Groups

Science.gov (United States)

Ryberg, Thomas; Davidsen, Jacob; Hodgson, Vivien

2018-01-01

The paper builds on the work of Rossitto "et al." on collaborative nomadic work to develop three categories of practice of nomadic collaborative learning groups. Our study is based on interviews, workshops and observations of two undergraduate student's group practices engaged in self-organised, long-term collaborations within the frame…

Collaborative Improvement

DEFF Research Database (Denmark)

Kaltoft, Rasmus

-organisational continuous improvement of their performance, relative to that of other EMEs. Developing a collaborative improvement relationship between companies is a protracted and complex process and, according to some surveys, the failure rate is as low as one to three. This failure rate is affected by a whole range...... of factors. The research presented in this thesis was aimed at identifying these factors and investigating their interplay and influence on the progress and success of the development of the collaborative improvement. This thesis presents our findings regarding the factors found, their interplay...

76 FR 23171 - Electric Reliability Organization Interpretations of Interconnection Reliability Operations and...

Science.gov (United States)

2011-04-26

... Reliability Standards for the Bulk-Power System, Order No. 693, FERC Stats. & Regs. ] 31,242, order on reh'g...-Power System reliability may request an interpretation of a Reliability Standard.\\7\\ The ERO's standards... information in its reliability assessments. The Reliability Coordinator must monitor Bulk Electric System...

Metrics Are Needed for Collaborative Software Development

Directory of Open Access Journals (Sweden)

Mojgan Mohtashami

2011-10-01

Full Text Available There is a need for metrics for inter-organizational collaborative software development projects, encompassing management and technical concerns. In particular, metrics are needed that are aimed at the collaborative aspect itself, such as readiness for collaboration, the quality and/or the costs and benefits of collaboration in a specific ongoing project. We suggest questions and directions for such metrics, spanning the full lifespan of a collaborative project, from considering the suitability of collaboration through evaluating ongoing projects to final evaluation of the collaboration.

Evaluation of Intelligent Grouping Based on Learners' Collaboration Competence Level in Online Collaborative Learning Environment

Science.gov (United States)

Muuro, Maina Elizaphan; Oboko, Robert; Wagacha, Waiganjo Peter

2016-01-01

In this paper we explore the impact of an intelligent grouping algorithm based on learners' collaborative competency when compared with (a) instructor based Grade Point Average (GPA) method level and (b) random method, on group outcomes and group collaboration problems in an online collaborative learning environment. An intelligent grouping…

Does Telecare Improve Interorganisational Collaboration?

Directory of Open Access Journals (Sweden)

Jannie Kristine Bang Christensen

2016-11-01

Full Text Available Introduction: Previous studies have suggested that telecare can improve interorganisational collaboration within fragmented health care systems, yet this outcome has not been examined in a large-scale setting. This study explores the effects of a large-scale interorganisational telecare programme in Denmark based on home-monitoring on collaboration in a telecare network between municipalities, hospitals, and general practitioners. Methodology: Semi-structured interviews and observations of collaborating health professionals from the municipalities, hospitals, and general practitioners were undertaken and then repeated a year later. Collaboration was analysed both at the interorganisational network level and within each part of the network, including its interrelations. Results: Collaboration between municipalities and general practitioners was initially intensified as a result of implementing telecare, though this changed over time as the first start-up obstacles were overcome and the patients became more active in their treatment. Conversely, collaboration between 'hospitals and municipalities' and 'hospitals and general practitioners' was unaffected by telecare. Discussion: Changes in collaboration among municipal nurses, general practitioners, and hospital staff were related to dependency structures and municipalities’ newly gained central role in a telecare network. While the telecare network was initially characterised by asymmetrical dependency structures, these were partially equalised over time because of the municipalities’ new position in the network.

Wikis and Collaborative Learning in Higher Education

Science.gov (United States)

Zheng, Binbin; Niiya, Melissa; Warschauer, Mark

2015-01-01

While collaborative learning and collaborative writing can be of great value to student learning, the implementation of a technology-supported collaborative learning environment is a challenge. With their built-in features for supporting collaborative writing and social communication, wikis are a promising platform for collaborative learning;…

Pooling and expanding registries of familial hypercholesterolaemia to assess gaps in care and improve disease management and outcomes: Rationale and design of the global EAS Familial Hypercholesterolaemia Studies Collaboration

NARCIS (Netherlands)

Vallejo-Vaz, Antonio J.; Akram, Asif; Kondapally Seshasai, Sreenivasa Rao; Cole, Della; Watts, Gerald F.; Hovingh, G. Kees; Kastelein, John J. P.; Mata, Pedro; Raal, Frederick J.; Santos, Raul D.; Soran, Handrean; Freiberger, Tomas; Abifadel, Marianne; Aguilar-Salinas, Carlos A.; Alnouri, Fahad; Alonso, Rodrigo; Al-Rasadi, Khalid; Banach, Maciej; Bogsrud, Martin P.; Bourbon, Mafalda; Bruckert, Eric; Car, Josip; Ceska, Richard; Corral, Pablo; Descamps, Olivier; Dieplinger, Hans; Do, Can T.; Durst, Ronen; Ezhov, Marat V.; Fras, Zlatko; Gaita, Dan; Gaspar, Isabel M.; Genest, Jaques; Harada-Shiba, Mariko; Jiang, Lixin; Kayikcioglu, Meral; Lam, Carolyn S. P.; Latkovskis, Gustavs; Laufs, Ulrich; Liberopoulos, Evangelos; Lin, Jie; Lin, Nan; Maher, Vincent; Majano, Nelson; Marais, A. David; März, Winfried; Mirrakhimov, Erkin; Miserez, André R.; Mitchenko, Olena; Nawawi, Hapizah; Nilsson, Lennart; Nordestgaard, Børge G.; Paragh, György; Petrulioniene, Zaneta; Pojskic, Belma; Reiner, Željko; Sahebkar, Amirhossein; Santos, Lourdes E.; Schunkert, Heribert; Shehab, Abdullah; Slimane, M. Naceur; Stoll, Mario; Su, Ta-Chen; Susekov, Andrey; Tilney, Myra; Tomlinson, Brian; Tselepis, Alexandros D.; Vohnout, Branislav; Widén, Elisabeth; Yamashita, Shizuya; Catapano, Alberico L.; Ray, Kausik K.

2016-01-01

Background: The potential for global collaborations to better inform public health policy regarding major non-hypercholesterolaemia (FH), a common genetic disorder associated with premature cardiovascular disease, is yet to be reliably ascertained using similar approaches. The European

Principles of performance and reliability modeling and evaluation essays in honor of Kishor Trivedi on his 70th birthday

CERN Document Server

Puliafito, Antonio

2016-01-01

This book presents the latest key research into the performance and reliability aspects of dependable fault-tolerant systems and features commentary on the fields studied by Prof. Kishor S. Trivedi during his distinguished career. Analyzing system evaluation as a fundamental tenet in the design of modern systems, this book uses performance and dependability as common measures and covers novel ideas, methods, algorithms, techniques, and tools for the in-depth study of the performance and reliability aspects of dependable fault-tolerant systems. It identifies the current challenges that designers and practitioners must face in order to ensure the reliability, availability, and performance of systems, with special focus on their dynamic behaviors and dependencies, and provides system researchers, performance analysts, and practitioners with the tools to address these challenges in their work. With contributions from Prof. Trivedi's former PhD students and collaborators, many of whom are internationally recognize...

Collaborative Contracting in Projects

NARCIS (Netherlands)

Suprapto, M.

2016-01-01

Project practitioners have increasingly recognized the importance of collaborative relationships to ensure successful executions of projects. However, the ability to sustain and consistenly drive real collaborative attitudes and behavior for achieving the desired outcomes remains of enduring

Mapping the research on scientific collaboration

Institute of Scientific and Technical Information of China (English)

HOU Jianhua; CHEN Chaomei; YAN Jianxin

2010-01-01

The aim of this paper was to identify the trends and hot topics in the study of scientific collaboration via scientometric analysis.Information visualization and knowledge domain visualization techniques were adopted to determine how the study of scientific collaboration has evolved.A total of 1,455 articles on scientific cooperation published between 1993 and 2007 were retrieved from the SCI,SSCI and A&HCI databases with a topic search of scientific collaboration or scientific cooperation for the analysis.By using CiteSpace,the knowledge bases,research foci,and research fronts in the field of scientific collaboration were studied.The results indicated that research fronts and research foci are highly consistent in terms of the concept,origin,measurement,and theory of scientific collaboration.It also revealed that research fronts included scientific collaboration networks,international scientific collaboration,social network analysis and techniques,and applications of bibliometrical indicators,webmetrics,and health care related areas.

Are you a collaborative leader?

Science.gov (United States)

Ibarra, Herminia; Hansen, Morten T

2011-01-01

Social media and technologies have put connectivity on steroids and made collaboration more integral to business than ever. But without the right leadership, collaboration can go astray. Employees who try to collaborate on everything may wind up stuck in endless meetings, struggling to reach agreement. On the other side of the coin, executives who came of age during the heyday of "command and control" management can have trouble adjusting their style to fit the new realities. In their research on top-performing CEOs, Insead professors Ibarra and Hansen have examined what it takes to be a collaborative leader. They've found that it requires connecting people and ideas outside an organization to those inside it, leveraging diverse talent, modeling collaborative behavior at the top, and showing a strong hand to keep teams from getting mired in debate. In this article, they describe tactics that executives from Akamai, GE, Reckitt Benckiser, and other firms use in those four areas and how they foster high-performance collaborative cultures in their organizations.

Collaborative engagement experiment (CEE)

Science.gov (United States)

Wade, Robert L.; Reames, Joseph M.

2005-05-01

Unmanned ground and air systems operating in collaboration have the potential to provide future Joint Forces a significant capability for operations in complex terrain. Ground and air collaborative engagements potentially offer force conservation, perform timely acquisition and dissemination of essential combat information, and can eliminate high value and time critical targets. These engagements can also add considerably to force survivability by reducing soldier and equipment exposure during critical operations. The Office of the Secretary of Defense, Joint Robotics Program (JRP) sponsored Collaborative Engagement Experiment (CEE) is a consolidation of separate Air Force, Army and Navy collaborative efforts to provide a Joint capability. The Air Force Research Laboratory (AFRL), Material and Manufacturing Directorate, Aerospace Expeditionary Force Division, Force Protection Branch (AFRLMLQF), The Army Aviation and Missile Research, Development and Engineering Center (AMRDEC) Joint Technology Center (JTC)/Systems Integration Laboratory (SIL), and the Space and Naval Warfare Systems Center-San Diego (SSC San Diego) are conducting technical research and proof of principle for an envisioned operational concept for extended range, three dimensional, collaborative operations between unmanned systems, with enhanced situational awareness for lethal operations in complex terrain. This program will assess information requirements and conduct experiments to identify and resolve technical risks for collaborative engagements using Unmanned Ground Vehicles (UGVs) and Unmanned Aerial Vehicles (UAVs). It will research, develop and physically integrate multiple unmanned systems and conduct live collaborative experiments. Modeling and Simulation systems will be upgraded to reflect engineering fidelity levels to greater understand technical challenges to operate as a team. This paper will provide an update of a multi-year program and will concentrate primarily on the JTC

Fast calculation of magnetic field distribution in magnetic gear for high torque application

DEFF Research Database (Denmark)

Zhang, Xiaoxu; Liu, Xiao; Song, Zhanfeng

2016-01-01

burden if finite element method (FEM) is employed. Analytical methods are therefore expected. To date, only the exact subdomain model is capable of precisely predicting the magnetic field behaviors in an analytical manner through solving a matrix equation. However, as pole number of the CMG increases......For applications demanding high torque and high reliability transmission, coaxial magnetic gear (CMG) may be a promising substitute of the mechanical gearbox. However, with the increasing of unit capacity, CMG tends to have a big size with large pole number, which would lead to heavy computation...

The next frontier: Bringing collaborative care to scale.

Science.gov (United States)

Levkovich, Natalie

2015-12-01

In my position as CEO of the Health Federation of Philadelphia (HFP), I am acutely aware of the effort required to implement practice transformation, including fully integrated behavioral health (IBH) and primary care. We integrate knowledge of our marketplace, best practices from the field, and the wisdom of our providers to achieve our practice goals. We have found this to be a key to the success of our advocacy, efficient replication, and rapid regional spread of IBH. Even when payment models, the other driving barrier to IBH, catch up and reflect a better fit with the demands of efficiently integrated, whole-person, teambased care, the challenges resulting from lack of implementation support will still exist. That's where the Collaborative Family Healthcare Association (CFHA) comes in. CFHA can be that centralized and reliable structure to help guide the planning and application of the essential core elements of integrated care: aligned systems, metrics and operations; patient and family centered approaches; workforce competencies; and strategies for stakeholder engagement. In spite of its influence, integrity, and accomplishments, CFHA is still a "too-well-kept secret." By embracing a focused approach, strategic partnerships, clear communication of our unique strengths and capabilities, and the collective might that exists within our own CFHA family, CFHA can grow and thrive and continue to lead the field of collaborative family health care. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Distance collaborations with industry

Energy Technology Data Exchange (ETDEWEB)

Peskin, A.; Swyler, K.

1998-06-01

The college industry relationship has been identified as a key policy issue in Engineering Education. Collaborations between academic institutions and the industrial sector have a long history and a bright future. For Engineering and Engineering Technology programs in particular, industry has played a crucial role in many areas including advisement, financial support, and practical training of both faculty and students. Among the most important and intimate interactions are collaborative projects and formal cooperative education arrangements. Most recently, such collaborations have taken on a new dimension, as advances in technology have made possible meaningful technical collaboration at a distance. There are several obvious technology areas that have contributed significantly to this trend. Foremost is the ubiquitous presence of the Internet. Perhaps almost as important are advances in computer based imaging. Because visual images offer a compelling user experience, it affords greater knowledge transfer efficiency than other modes of delivery. Furthermore, the quality of the image appears to have a strongly correlated effect on insight. A good visualization facility offers both a means for communication and a shared information space for the subjects, which are among the essential features of both peer collaboration and distance learning.

Manipulation Robustness of Collaborative Filtering

OpenAIRE

Benjamin Van Roy; Xiang Yan

2010-01-01

A collaborative filtering system recommends to users products that similar users like. Collaborative filtering systems influence purchase decisions and hence have become targets of manipulation by unscrupulous vendors. We demonstrate that nearest neighbors algorithms, which are widely used in commercial systems, are highly susceptible to manipulation and introduce new collaborative filtering algorithms that are relatively robust.

DISTRIBUTED LEADERSHIP COLLABORATION FACTORS TO SUPPORT IDEA GENERATION IN COMPUTER-SUPPORTED COLLABORATIVE e-LEARNING

Directory of Open Access Journals (Sweden)

Niki Lambropoulos

2011-01-01

Full Text Available This paper aims to identify, discuss and analyze students’ collaboration factors related to distributed leadership (DL, which correlates with interaction quality evident in idea generation. Scripting computer-supported collaborative e-learning (CSCeL activities based on DL can scaffold students’ interactions that support collaboration and promote idea generation. Furthermore, the associated tools can facilitate collaboration via scripting and shed light on students’ interactions and dialogical sequences. Such detailed planning can result in effective short e-courses. In this case study, 21 MSc students’ teams worked on a DL project within a 2-day e-course at the IT Institute (ITIN, France. The research methods involved a self-reported questionnaire; the Non-Negative Matrix Factorization (NNMF algorithm with qualitative analysis; and outcomes from the Social Network Analysis (SNA tools implemented within the forums. The results indicated that scripting DL based on the identified distributed leadership attributes can support values such as collaboration and can be useful in supporting idea generation in short e-courses.

Managing collaboration in the nanoManipulator

DEFF Research Database (Denmark)

Hudson, Thomas C.; Heiser, Aron T.; Sonnenwald, Diane H.

2003-01-01

We designed, developed, deployed, and evaluated the Collaborative nanoManipulator (CnM), a system supporting remote collaboration between users of the nanoManipulator interface to atomic force microscopes. To be accepted by users, the shared nanoManipulator application had to have the same high...... level of interactivity as the single user system and the application had to support a user's ability to interleave working privately and working collaboratively. This paper briefly describes the entire collaboration system, but focuses on the shared nanoManipulator application. Based on our experience...... developing the CnM, we present: a method of analyzing applications to characterize the requirements for sharing data between collaborating sites, examples of data structures that support collaboration, and guidelines for selecting appropriate synchronization and concurrency control schemes....

Supporting collaborative computing and interaction

International Nuclear Information System (INIS)

Agarwal, Deborah; McParland, Charles; Perry, Marcia

2002-01-01

To enable collaboration on the daily tasks involved in scientific research, collaborative frameworks should provide lightweight and ubiquitous components that support a wide variety of interaction modes. We envision a collaborative environment as one that provides a persistent space within which participants can locate each other, exchange synchronous and asynchronous messages, share documents and applications, share workflow, and hold videoconferences. We are developing the Pervasive Collaborative Computing Environment (PCCE) as such an environment. The PCCE will provide integrated tools to support shared computing and task control and monitoring. This paper describes the PCCE and the rationale for its design

Information handling in collaborative research

Directory of Open Access Journals (Sweden)

Ellen Collins

2013-02-01

Full Text Available UK public policy makers have a growing interest in collaborative research, where academics work with public, private or third sector partners on a joint project which supports the partner’s aims. This paper reports on the findings of five case studies, looking at how information is sourced, managed, used and shared within collaborative research projects. It finds that researchers within collaborative projects have similar information management issues as are known to exist within academia more broadly, but that the specific conditions which govern research collaborations mean that interventions to improve or support information management must be carefully tailored.

Understanding nomadic collaborative learning groups

DEFF Research Database (Denmark)

Ryberg, Thomas; Davidsen, Jacob; Hodgson, Vivien

2018-01-01

-term collaborations within the frame of Problem and Project Based Learning. By analysing the patterns of nomadic collaborative learning we identify and discuss how the two groups of students incorporate mobile and digital technologies as well as physical and/or non-digital technologies into their group work......The paper builds on the work of Rossitto et al. on collaborative nomadic work to develop three categories of practice of nomadic collaborative learning groups. Our study is based on interviews, workshops and observations of two undergraduate student's group practices engaged in self-organised, long....... Specifically, we identify the following categories of nomadic collaborative learning practices: “orchestration of work phases, spaces and activities,” “the orchestration of multiple technologies” and “orchestration of togetherness.” We found that for both groups of students there was a fluidity, situatedness...

Supporting Dynamic Ad hoc Collaboration Capabilities

CERN Document Server

Agarwal, D

2003-01-01

Modern HENP experiments such as CMS and Atlas involve as many as 2000 collaborators around the world. Collaborations this large will be unable to meet often enough to support working closely together. Many of the tools currently available for collaboration focus on heavy-weight applications such as videoconferencing tools. While these are important, there is a more basic need for tools that support connecting physicists to work together on an ad hoc or continuous basis. Tools that support the day-to-day connectivity and underlying needs of a group of collaborators are important for providing light-weight, non-intrusive, and flexible ways to work collaboratively. Some example tools include messaging, file-sharing, and shared plot viewers. An important component of the environment is a scalable underlying communication framework. In this paper we will describe our current progress on building a dynamic and ad hoc collaboration environment and our vision for its evolution into a HENP collaboration environment.

Supporting Dynamic Ad hoc Collaboration Capabilities

International Nuclear Information System (INIS)

Agarwal, Deborah A.; Berket, Karlo

2003-01-01

Modern HENP experiments such as CMS and Atlas involve as many as 2000 collaborators around the world. Collaborations this large will be unable to meet often enough to support working closely together. Many of the tools currently available for collaboration focus on heavy-weight applications such as videoconferencing tools. While these are important, there is a more basic need for tools that support connecting physicists to work together on an ad hoc or continuous basis. Tools that support the day-to-day connectivity and underlying needs of a group of collaborators are important for providing light-weight, non-intrusive, and flexible ways to work collaboratively. Some example tools include messaging, file-sharing, and shared plot viewers. An important component of the environment is a scalable underlying communication framework. In this paper we will describe our current progress on building a dynamic and ad hoc collaboration environment and our vision for its evolution into a HENP collaboration environment

A collaborative virtual environment for training of security agents in nuclear emergencies

Energy Technology Data Exchange (ETDEWEB)

Fernandes, Sara I.; Passos, Cláudio A.; Silva, Marcio H.; Carvalho, Paulo Victor R.; Legey, Ana Paula; Mol, Antonio Carlos; Machado, Daniel M.; Cotelli, André; Rocha, Tiago L., E-mail: mol@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Departamento de Realidade Virtual

2017-07-01

In face the recently observed security menaces related to terrorist actions and natural disasters, there is a need for a major qualification and training of the agents responsible for avoid any problems regarding to abnormal conditions. In the conventional training procedures, however, field simulations are associated to logistical and operational constraints regarded to the execution of the tests which can expose the user to risk. On the other hand, the use of virtual simulations provides an alternative to such limitations besides of promote the qualifying of professionals with a great reliability. For this reason, this paper proposes the development of a collaborative virtual environment that will be used to prepare the security agents on identifying individuals suspected of carrying radioactive materials. The development of the virtual environment consisted on modeling using Autodesk 3ds Max, where the scene itself and the scene objects were modeled besides the terrain creation and basic features programming using the Game Engine Unity 3D. In the Engine Game were included radiation detectors and avatars. The security agents were able to communicate to each other by means of auxiliary external tools like a headset software that makes possible the communication, coordination and cooperation required for an effective collaboration. Experimental tests of the virtual simulations were performed with the participation of CNEN radiological protection agents and collaborators. The tests have shown that the proposed method can contribute to improve the training results of the basic collaborative skills required for a CNEN agent in an emergency situation without the need to expose him to any kind of risk. In face of that, we hope that it can contribute to minimize the demand for qualified security professionals. (author)

A collaborative virtual environment for training of security agents in nuclear emergencies

International Nuclear Information System (INIS)

Fernandes, Sara I.; Passos, Cláudio A.; Silva, Marcio H.; Carvalho, Paulo Victor R.; Legey, Ana Paula; Mol, Antonio Carlos; Machado, Daniel M.; Cotelli, André; Rocha, Tiago L.

2017-01-01

In face the recently observed security menaces related to terrorist actions and natural disasters, there is a need for a major qualification and training of the agents responsible for avoid any problems regarding to abnormal conditions. In the conventional training procedures, however, field simulations are associated to logistical and operational constraints regarded to the execution of the tests which can expose the user to risk. On the other hand, the use of virtual simulations provides an alternative to such limitations besides of promote the qualifying of professionals with a great reliability. For this reason, this paper proposes the development of a collaborative virtual environment that will be used to prepare the security agents on identifying individuals suspected of carrying radioactive materials. The development of the virtual environment consisted on modeling using Autodesk 3ds Max, where the scene itself and the scene objects were modeled besides the terrain creation and basic features programming using the Game Engine Unity 3D. In the Engine Game were included radiation detectors and avatars. The security agents were able to communicate to each other by means of auxiliary external tools like a headset software that makes possible the communication, coordination and cooperation required for an effective collaboration. Experimental tests of the virtual simulations were performed with the participation of CNEN radiological protection agents and collaborators. The tests have shown that the proposed method can contribute to improve the training results of the basic collaborative skills required for a CNEN agent in an emergency situation without the need to expose him to any kind of risk. In face of that, we hope that it can contribute to minimize the demand for qualified security professionals. (author)

Helen Kim as New Woman and Collaborator: A Comprehensive Assessment of Korean Collaboration under Japanese Colonial Rule

Directory of Open Access Journals (Sweden)

AhRan Ellie Bae

2017-02-01

Full Text Available Although almost seventy years has passed since Korea's liberation from Japanese rule, the issue of collaboration still haunts Korea today. Attempts to resolve this issue have tended to focus attention on the traitorous actions of "collaborators" without considering the gray areas that surround their actions such as the circumstances that influenced the accused to commit their alleged traitorous acts and the intentions that drove their decisions. Helen Kim, as a "new woman" and an educator, valued the necessity of providing education for women. Yet, her efforts to realize this goal, to the contrary, forced her into actions that would later be used to construct a reputation as a Japanese collaborator. Korea's nationalist historiography has a tendency to polarize this issue by categorizing a "collaborator" as either a traitor or a patriot. However, when we take a closer look at these collaborators' lives, we discover that most collaboration happened in gray areas where it is often difficult to clearly draw a line between treason and collaboration. Helen Kim's case suggests that the issue of collaboration cannot be fully explained by nationalist historiography's framework and we must give attention to these gray areas. Through her story I hope to complicate the issue of collaboration by raising questions that address the gray areas that surround the actions of "collaborators." In doing so, I hope to challenge the nationalist historiography's propensity to oversimplify this issue and present a more nuanced understanding of it.

Enabling distributed collaborative science

DEFF Research Database (Denmark)

Hudson, T.; Sonnenwald, Diane H.; Maglaughlin, K.

2000-01-01

To enable collaboration over distance, a collaborative environment that uses a specialized scientific instrument called a nanoManipulator is evaluated. The nanoManipulator incorporates visualization and force feedback technology to allow scientists to see, feel, and modify biological samples bein...

Privacy-Preserving Collaborative Sequential Pattern Mining

National Research Council Canada - National Science Library

Zhan, Justin Z; Chang, LiWu; Matwin, Stan

2004-01-01

.... During the collaboration, each party of the collaboration needs to share its data with other parties. If the parties don't care about their data privacy, the collaboration can be easily achieved...

Reliable computer systems.

Science.gov (United States)

Wear, L L; Pinkert, J R

1993-11-01

In this article, we looked at some decisions that apply to the design of reliable computer systems. We began with a discussion of several terms such as testability, then described some systems that call for highly reliable hardware and software. The article concluded with a discussion of methods that can be used to achieve higher reliability in computer systems. Reliability and fault tolerance in computers probably will continue to grow in importance. As more and more systems are computerized, people will want assurances about the reliability of these systems, and their ability to work properly even when sub-systems fail.

Securing collaborative environments

Energy Technology Data Exchange (ETDEWEB)

Agarwal, Deborah [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Jackson, Keith [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Thompson, Mary [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2002-05-16

The diverse set of organizations and software components involved in a typical collaboratory make providing a seamless security solution difficult. In addition, the users need support for a broad range of frequency and locations for access to the collaboratory. A collaboratory security solution needs to be robust enough to ensure that valid participants are not denied access because of its failure. There are many tools that can be applied to the task of securing collaborative environments and these include public key infrastructure, secure sockets layer, Kerberos, virtual and real private networks, grid security infrastructure, and username/password. A combination of these mechanisms can provide effective secure collaboration capabilities. In this paper, we discuss the requirements of typical collaboratories and some proposals for applying various security mechanisms to collaborative environments.

78 FR 41339 - Electric Reliability Organization Proposal To Retire Requirements in Reliability Standards

Science.gov (United States)

2013-07-10

...] Electric Reliability Organization Proposal To Retire Requirements in Reliability Standards AGENCY: Federal... Reliability Standards identified by the North American Electric Reliability Corporation (NERC), the Commission-certified Electric Reliability Organization. FOR FURTHER INFORMATION CONTACT: Kevin Ryan (Legal Information...

Collaborating with Rising Stars

DEFF Research Database (Denmark)

Andersen, Kristina Vaarst; Mors, Marie Louise; Jeppesen, Jacob

2018-01-01

Status provides preferential access to resources, as well as favorable judgment, which in turn may lead to increases in performance. Prior work has established that such benefits even spill over between collaboration partners, thus allowing collaboration partners of high status individuals to bas...

Collaboration in teacher teams

NARCIS (Netherlands)

Brouwer, P.

2011-01-01

In order to deal with innovations and the associated complexity of work, ongoing collaboration between teachers has become more important in secondary education. Teacher collaboration is one of the factors that contribute to the successful implementation of innovations in secondary schools. However,

76 FR 58101 - Electric Reliability Organization Interpretation of Transmission Operations Reliability Standard

Science.gov (United States)

2011-09-20

....C. Cir. 2009). \\4\\ Mandatory Reliability Standards for the Bulk-Power System, Order No. 693, FERC... for maintaining real and reactive power balance. \\14\\ Electric Reliability Organization Interpretation...; Order No. 753] Electric Reliability Organization Interpretation of Transmission Operations Reliability...

Designing for collaborative interpretation in telemonitoring

DEFF Research Database (Denmark)

Andersen, Tariq Osman; Bjørn, Pernille; Kensing, Finn

2011-01-01

with a design interventionist perspective was conducted to investigate the telemonitoring arrangement for chronic heart patients with ICDs and to identify the nature of the collaborative practices involved in ICD data interpretation. We diagnose the main challenges involved in collaborative interpretation...... practices. These insights were used to re-design the socio-technical setup of the telemonitoring practices by designing and building a web-based, patient-centric, collaborative application, myRecord, to re-introduce the patients as active participants into the telemonitoring setup. Finally, we introduce my......Record at Copenhagen University Hospital and evaluate the new practices and the collaborative technology related to the transformed role of the patients. Results: The interpretation of ICD data is a collaborative practice engaging clinicians and patients and involving three separate collaborative processes...

76 FR 42534 - Mandatory Reliability Standards for Interconnection Reliability Operating Limits; System...

Science.gov (United States)

2011-07-19

... Reliability Operating Limits; System Restoration Reliability Standards AGENCY: Federal Energy Regulatory... data necessary to analyze and monitor Interconnection Reliability Operating Limits (IROL) within its... Interconnection Reliability Operating Limits, Order No. 748, 134 FERC ] 61,213 (2011). \\2\\ The term ``Wide-Area...

Embarrassing To Collaborate

DEFF Research Database (Denmark)

Mitchell, Robb

This position paper briefly outlines my interest in embarrassment– principally in relation to experiments provoking collaborative encounters in contexts that range from urban spaces to art galleries, and from music events to industrial innovation workshops.......This position paper briefly outlines my interest in embarrassment– principally in relation to experiments provoking collaborative encounters in contexts that range from urban spaces to art galleries, and from music events to industrial innovation workshops....

Communication and collaboration technologies.

Science.gov (United States)

Cheeseman, Susan E

2012-01-01

This is the third in a series of columns exploring health information technology (HIT) in the neonatal intensive care unit (NICU). The first column provided background information on the implementation of information technology throughout the health care delivery system, as well as the requisite informatics competencies needed for nurses to fully engage in the digital era of health care. The second column focused on information and resources to master basic computer competencies described by the TIGER initiative (Technology Informatics Guiding Education Reform) as learning about computers, computer networks, and the transfer of data.1 This column will provide additional information related to basic computer competencies, focusing on communication and collaboration technologies. Computers and the Internet have transformed the way we communicate and collaborate. Electronic communication is the ability to exchange information through the use of computer equipment and software.2 Broadly defined, any technology that facilitates linking one or more individuals together is a collaborative tool. Collaboration using technology encompasses an extensive range of applications that enable groups of individuals to work together including e-mail, instant messaging (IM ), and several web applications collectively referred to as Web 2.0 technologies. The term Web 2.0 refers to web applications where users interact and collaborate with each other in a collective exchange of ideas generating content in a virtual community. Examples of Web 2.0 technologies include social networking sites, blogs, wikis, video sharing sites, and mashups. Many organizations are developing collaborative strategies and tools for employees to connect and interact using web-based social media technologies.3.

Literacy Education and Interprofessional Collaboration

Directory of Open Access Journals (Sweden)

Joron Pihl

2012-03-01

Full Text Available The aim of this article is to explore inter-professional collaboration in literacy education. It examines factors that facilitate collaboration between teachers and librarians and the contributions to literacy education. The study was designed as a research and development project in multicultural schools in Norway (2007-2011. Its theoretical framework was cultural-historical theory of activity theory, and the theory of expansive learning. The methods were formative intervention, interviews, participant observation, and qualitative and quantitative analysis of student literacy. In the study, interprofessional collaboration made significant contributions to professional development and literacy education. Interprofessional collaboration was developed as a collective learning process. It was facilitated by research interventions, development of a shared object of activity and work with new theoretical concepts and cultural artefacts. The findings indicate that inter-professional collaboration can make important contributions to realization of the mandate of the teaching and library profession.

76 FR 66055 - North American Electric Reliability Corporation; Order Approving Interpretation of Reliability...

Science.gov (United States)

2011-10-25

...\\ Mandatory Reliability Standards for the Bulk-Power System, Order No. 693, FERC Stats. & Regs. ] 31,242... materially affected'' by Bulk-Power System reliability may request an interpretation of a Reliability... Electric Reliability Corporation; Order Approving Interpretation of Reliability Standard; Before...

Assessment of microelectronics packaging for high temperature, high reliability applications

Energy Technology Data Exchange (ETDEWEB)

Uribe, F.

1997-04-01

This report details characterization and development activities in electronic packaging for high temperature applications. This project was conducted through a Department of Energy sponsored Cooperative Research and Development Agreement between Sandia National Laboratories and General Motors. Even though the target application of this collaborative effort is an automotive electronic throttle control system which would be located in the engine compartment, results of this work are directly applicable to Sandia`s national security mission. The component count associated with the throttle control dictates the use of high density packaging not offered by conventional surface mount. An enabling packaging technology was selected and thermal models defined which characterized the thermal and mechanical response of the throttle control module. These models were used to optimize thick film multichip module design, characterize the thermal signatures of the electronic components inside the module, and to determine the temperature field and resulting thermal stresses under conditions that may be encountered during the operational life of the throttle control module. Because the need to use unpackaged devices limits the level of testing that can be performed either at the wafer level or as individual dice, an approach to assure a high level of reliability of the unpackaged components was formulated. Component assembly and interconnect technologies were also evaluated and characterized for high temperature applications. Electrical, mechanical and chemical characterizations of enabling die and component attach technologies were performed. Additionally, studies were conducted to assess the performance and reliability of gold and aluminum wire bonding to thick film conductor inks. Kinetic models were developed and validated to estimate wire bond reliability.

Stakeholder collaboration and heritage management

OpenAIRE

Aas, C.; Ladkin, Adele; Fletcher, John

2005-01-01

This article examines a collaborative approach to the relationship between heritage management and tourism development in Luang Prabang, Laos. The purpose is to examine stakeholder collaboration and management roles, heritage tourism development, as well as the interdependence of the heritage conservation and tourism relationship. The research examines a UNESCO/Norwegian government project, which aiming to promote collaboration between heritage conservation and tourism through stakeholder inv...

The korean version of the body image scale-reliability and validity in a sample of breast cancer patients.

Science.gov (United States)

Khang, Dongwoo; Rim, Hyo-Deog; Woo, Jungmin

2013-03-01

The Body Image Scale (BIS) developed in collaboration with the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Study Group is a brief questionnaire for measuring body image concerns in patients with cancer. This study sought to assess the reliability and validity of the Korean version of the Body Image Scale (K-BIS). The participants consisted of 155 postoperative breast cancer patients (56 breast conserving surgery, 56 mastectomy, and 43 oncoplastic surgery). Subjects were evaluated using the K-BIS, the Body-Esteem Scale for Adolescents and Adults (BESAA), the Rosenberg Self-Esteem Scale (RSES), the Hospital Anxiety and Depression Scale (HADS), and the World Health Organization Quality of Life Scale Abbreviated Version (WHOQOL-BREF). Test-retest reliability and internal consistency were examined as a measure of reliability and validity was evaluated by convergent validity, discriminant validity and factor analysis. Cronbach's α value was 0.943. The total score of the K-BIS was negatively correlated with the BESAA (r=0.301, p59% variance. The K-BIS showed good reliability and validity for assessment of body image in Korean breast cancer patients.

Managing collaboration in the nanoManipulator

DEFF Research Database (Denmark)

Hudson, Thomas C.; Helser, Aren T.; Sonnenwald, Diane H.

2004-01-01

We designed, developed, deployed, and evaluated the Collaborative nanoManipulator (CnM), a distributed, collaborative virtual environment system supporting remote scientific collaboration between users of the nanoManipulator interface to atomic force microscopes. This paper describes the entire...

International tuberculosis research collaborations within Asia.

Science.gov (United States)

Molton, James S; Singh, Shweta; Chen, Ling Jun; Paton, Nicholas I

2017-09-07

Asia bears more than half the global tuberculosis (TB) burden. Economic development in the region has increased available funding for biomedical research and opportunity for collaboration. We explored the extent of international tuberculosis research collaborations between institutions within Asia. We conducted a Pubmed search for all articles with tuberculosis in the title published during a 12 month period with at least one author affiliation listed in Asia, then identified international collaborations from institution websites and internet searches. We identified 99 international collaborations involving an institution within Asia, of which only 8 (8.1%) were collaborations between Asian institutions. The remainder were with institutions outside of Asia. The paucity of intra-Asian international research collaboration represents a lost opportunity to optimise regional research funding, capacity building and the development of an Asia-relevant TB research agenda.

Researching collaboratively: implications for qualitative research and researchers.

Science.gov (United States)

Cheek, Julianne

2008-11-01

Often discussions about collaborative research, and collaboration generally, begin at the point of how to collaborate, who to collaborate with, and what to collaborate about. Rarely do they include equally important questions of why we are having discussions about collaboration, where such an impetus and emphasis is coming from, and how it connects to the contemporary political research context. In a recent editorial in Qualitative Health Research, Janice Morse highlighted the need for reflection about collaboration. This article responds to that call, providing reflections on collaboration, the imperative to collaborate, and what this all might mean for both qualitative research and qualitative researchers. I hope to stimulate new points of departure for thinking and action shaping collaborative research endeavors without-and just as crucially, within-qualitative research.

Inverse Reliability Task: Artificial Neural Networks and Reliability-Based Optimization Approaches

OpenAIRE

Lehký , David; Slowik , Ondřej; Novák , Drahomír

2014-01-01

Part 7: Genetic Algorithms; International audience; The paper presents two alternative approaches to solve inverse reliability task – to determine the design parameters to achieve desired target reliabilities. The first approach is based on utilization of artificial neural networks and small-sample simulation Latin hypercube sampling. The second approach considers inverse reliability task as reliability-based optimization task using double-loop method and also small-sample simulation. Efficie...

Intercultural Collaboration Stories

DEFF Research Database (Denmark)

Gertsen, Martine Cardel; Søderberg, Anne-Marie

2011-01-01

The objective of this article is to show how narrative methods provide useful tools for international business research. We do this by presenting a study of stories told about the collaboration between a Danish expatriate manager and his Chinese CEO in the Shanghai subsidiary of an MNE. First, we...... to elucidate intercultural collaboration processes by analyzing how each member of a dyad of interacting managers narrates the same chain of events. We show how the narratological concepts of peripeteia and anagnorisis are well suited to identifying focal points in their stories: situations where change...... follows their recognizing new dimensions of their conflicts, eventually furthering their collaboration. We explain how Greimas's actantial model is valuable when mapping differences between and changes in the narrators’ projects, alliances and oppositions in the course of their interaction. Thus, we make...

Dynamics of a split torque helicopter transmission. M.S. Thesis - Cleveland State Univ.

Science.gov (United States)

Krantz, Timothy L.

1994-01-01

Split torque designs, proposed as alternatives to traditional planetary designs for helicopter main rotor transmissions, can save weight and be more reliable than traditional designs. This report presents the results of an analytical study of the system dynamics and performance of a split torque gearbox that uses a balance beam mechanism for load sharing. The Lagrange method was applied to develop a system of equations of motion. The mathematical model includes time-varying gear mesh stiffness, friction, and manufacturing errors. Cornell's method for calculating the stiffness of spur gear teeth was extended and applied to helical gears. The phenomenon of sidebands spaced at shaft frequencies about gear mesh fundamental frequencies was simulated by modeling total composite gear errors as sinusoid functions. Although the gearbox has symmetric geometry, the loads and motions of the two power paths differ. Friction must be considered to properly evaluate the balance beam mechanism. For the design studied, the balance beam is not an effective device for load sharing unless the coefficient of friction is less than 0.003. The complete system stiffness as represented by the stiffness matrix used in this analysis must be considered to precisely determine the optimal tooth indexing position.

Dynamics of a split torque helicopter transmission

Science.gov (United States)

Krantz, Timothy L.

1994-06-01

Split torque designs, proposed as alternatives to traditional planetary designs for helicopter main rotor transmissions, can save weight and be more reliable than traditional designs. This report presents the results of an analytical study of the system dynamics and performance of a split torque gearbox that uses a balance beam mechanism for load sharing. The Lagrange method was applied to develop a system of equations of motion. The mathematical model includes time-varying gear mesh stiffness, friction, and manufacturing errors. Cornell's method for calculating the stiffness of spur gear teeth was extended and applied to helical gears. The phenomenon of sidebands spaced at shaft frequencies about gear mesh fundamental frequencies was simulated by modeling total composite gear errors as sinusoid functions. Although the gearbox has symmetric geometry, the loads and motions of the two power paths differ. Friction must be considered to properly evaluate the balance beam mechanism. For the design studied, the balance beam is not an effective device for load sharing unless the coefficient of friction is less than 0.003. The complete system stiffness as represented by the stiffness matrix used in this analysis must be considered to precisely determine the optimal tooth indexing position.

76 FR 23801 - North American Electric Reliability Corporation; Order Approving Reliability Standard

Science.gov (United States)

2011-04-28

... have an operating plan and facilities for backup functionality to ensure Bulk-Power System reliability... entity's primary control center on the reliability of the Bulk-Power System. \\1\\ Mandatory Reliability... potential impact of a violation of the Requirement on the reliability of the Bulk-Power System. The...

Collaborative Area Monitoring Using Wireless Sensor Networks with Stationary and Mobile Nodes

Directory of Open Access Journals (Sweden)

Theofanis P. Lambrou

2009-01-01

Full Text Available Monitoring a large area with stationary sensor networks requires a very large number of nodes which with current technology implies a prohibitive cost. The motivation of this work is to develop an architecture where a set of mobile sensors will collaborate with the stationary sensors in order to reliably detect and locate an event. The main idea of this collaborative architecture is that the mobile sensors should sample the areas that are least covered (monitored by the stationary sensors. Furthermore, when stationary sensors have a “suspicion” that an event may have occurred, they report it to a mobile sensor that can move closer to the suspected area and can confirm whether the event has occurred or not. An important component of the proposed architecture is that the mobile nodes autonomously decide their path based on local information (their own beliefs and measurements as well as information collected from the stationary sensors in a neighborhood around them. We believe that this approach is appropriate in the context of wireless sensor networks since it is not feasible to have an accurate global view of the state of the environment.

Electronic Collaboration Logbook

CERN Multimedia

CERN. Geneva

2012-01-01

At FNAL, we developed an Electronic Collaboration Logbook (ECL) application which is used by about 20 different collaborations, experiments and groups at FNAL. ECL is the latest iteration of the project formerly known as Control Room Logbook (CRL). We have been working on mobile (IOS and Android) clients for ECL. We will present history, current status and future plans of the project, as well as design, implementation and support solutions made by the project.

Suncor maintenance and reliability

Energy Technology Data Exchange (ETDEWEB)

Little, S. [Suncor Energy, Calgary, AB (Canada)

2006-07-01

Fleet maintenance and reliability at Suncor Energy was discussed in this presentation, with reference to Suncor Energy's primary and support equipment fleets. This paper also discussed Suncor Energy's maintenance and reliability standard involving people, processes and technology. An organizational maturity chart that graphed organizational learning against organizational performance was illustrated. The presentation also reviewed the maintenance and reliability framework; maintenance reliability model; the process overview of the maintenance and reliability standard; a process flow chart of maintenance strategies and programs; and an asset reliability improvement process flow chart. An example of an improvement initiative was included, with reference to a shovel reliability review; a dipper trip reliability investigation; bucket related failures by type and frequency; root cause analysis of the reliability process; and additional actions taken. Last, the presentation provided a graph of the results of the improvement initiative and presented the key lessons learned. tabs., figs.

Recommending Research Profiles for Multidisciplinary Academic Collaboration

Science.gov (United States)

Gunawardena, Sidath Deepal

2013-01-01

This research investigates how data on multidisciplinary collaborative experiences can be used to solve a novel problem: recommending research profiles of potential collaborators to academic researchers seeking to engage in multidisciplinary research collaboration. As the current domain theories of multidisciplinary collaboration are insufficient…

Formation of a collaborative society

OpenAIRE

Buřita, Ladislav; Ondryhal, Vojtěch

2014-01-01

The MilUNI knowledge portal, based on the knowledge base developed in ATOM software has been created at the authors' workplace with the aim to form a collaborative society of military universities. The analysis of the collaborative society concept is presented. The description of the MilUNI project is included. Some areas for university cooperation are proposed, as well as the measures facilitating the formation and development of the collaborative society.

Reliability and maintainability assessment factors for reliable fault-tolerant systems

Science.gov (United States)

Bavuso, S. J.

1984-01-01

A long term goal of the NASA Langley Research Center is the development of a reliability assessment methodology of sufficient power to enable the credible comparison of the stochastic attributes of one ultrareliable system design against others. This methodology, developed over a 10 year period, is a combined analytic and simulative technique. An analytic component is the Computer Aided Reliability Estimation capability, third generation, or simply CARE III. A simulative component is the Gate Logic Software Simulator capability, or GLOSS. The numerous factors that potentially have a degrading effect on system reliability and the ways in which these factors that are peculiar to highly reliable fault tolerant systems are accounted for in credible reliability assessments. Also presented are the modeling difficulties that result from their inclusion and the ways in which CARE III and GLOSS mitigate the intractability of the heretofore unworkable mathematics.

Collaborative Improvement

DEFF Research Database (Denmark)

Kaltoft, Rasmus

The thesis data have been collected in the EU-sponsored project: Collaborative Improvement Tool for the Extended Manufacturing Enterprise, CO-IMPROVE. In this project four universities (Denmark, Ireland, Italy, and The Netherlands), two software vendors (Greece and Sweden) and three companies...... (Denmark, Italy and The Netherlands) each with three to five suppliers were involved. The CO-IMPROVE project and the thesis is based on “action research” and “action learning”. The main aim of the whole project is through actual involvement and actions make the researchers, companies and selected suppliers...... learn how to improve operations in (hopefully) a win-win like manner through collaboration....

Collaboration enhances later individual memory for emotional material.

Science.gov (United States)

Bärthel, Gwennis A; Wessel, Ineke; Huntjens, Rafaële J C; Verwoerd, Johan

2017-05-01

Research on collaborative remembering suggests that collaboration hampers group memory (i.e., collaborative inhibition), yet enhances later individual memory. Studies examining collaborative effects on memory for emotional stimuli are scarce, especially concerning later individual memory. In the present study, female undergraduates watched an emotional movie and recalled it either collaboratively (n = 60) or individually (n = 60), followed by an individual free recall test and a recognition test. We replicated the standard collaborative inhibition effect. Further, in line with the literature, the collaborative condition displayed better post-collaborative individual memory. More importantly, in post-collaborative free recall, the centrality of the information to the movie plot did not play an important role. Recognition rendered slightly different results. Although collaboration rendered more correct recognition for more central details, it did not enhance recognition of background details. Secondly, the collaborative and individual conditions did not differ with respect to overlap of unique correct items in free recall. Yet, during recognition former collaborators more unanimously endorsed correct answers, as well as errors. Finally, extraversion, neuroticism, social anxiety, and depressive symptoms did not moderate the influence of collaboration on memory. Implications for the fields of forensic and clinical psychology are discussed.

Geo-collaboration under stress

NARCIS (Netherlands)

Looije, R.; Brake, G.M. te; Neerincx, M.A.

2007-01-01

“Most of the science and decision making involved in geo-information is the product of collaborative teams. Current geospatial technologies are a limiting factor because they do not provide any direct support for group efforts. In this paper we present a method to enhance geo-collaboration by

Social Media Collaboration in the Classroom

DEFF Research Database (Denmark)

Razmerita, Liana; Kirchner, Kathrin

2014-01-01

(including challenges) that influence the students’ overall satisfaction with collaboration? Does the usage of e-collaboration tools and social media usage influence collaboration satisfaction? The findings of the study are summarized in a model that point towards the main factors influencing student overall...

Contemporary collaborations between museums and universities

DEFF Research Database (Denmark)

Knudsen, Line Vestergaard; Simonsen, Celia Ekelund

2017-01-01

Numerous new types of cross-institutional collaborations have been conducted recently at the intersection between museums and universities. Museums of all subject areas have collaborated with university researchers, just as scholars from a broad range of disciplines including communications, media...... studies, IT and performance design and tourism increasingly collaborate with museums. Based on qualitative evaluation material and autobiographical experiences, this article analyzes a large Danish research project in which collaborations between several museums and universities took place. We investigate...

Editorial: Forms of Collaboration in Writing

Directory of Open Access Journals (Sweden)

Elke Van Steendam

2016-10-01

Full Text Available This paper introduces a special issue on forms of collaboration in writing. The four contributions in the issue present a range of perspectives on collaborating to produce and construct text. The studies are outcome-driven and/or process-oriented and use a range of research methodologies. Taken together, the papers in the issue confirm the complexity of collaboration in writing and show that many questions remain and much more research is needed. However, the papers also illustrate that the future research focus in collaborative writing might focus on the interactions of variables on the individual, collaborative and contextual level that count rather than the variables separately. Only an all-encompassing picture of the complex interplay between the different variables may allow us to grasp and exploit the full potential of collaborative writing both as an instructional or working method and as a research methodology.

Reliability Engineering

CERN Document Server

Lazzaroni, Massimo

2012-01-01

This book gives a practical guide for designers and users in Information and Communication Technology context. In particular, in the first Section, the definition of the fundamental terms according to the international standards are given. Then, some theoretical concepts and reliability models are presented in Chapters 2 and 3: the aim is to evaluate performance for components and systems and reliability growth. Chapter 4, by introducing the laboratory tests, puts in evidence the reliability concept from the experimental point of view. In ICT context, the failure rate for a given system can be

Reliability training

Science.gov (United States)

Lalli, Vincent R. (Editor); Malec, Henry A. (Editor); Dillard, Richard B.; Wong, Kam L.; Barber, Frank J.; Barina, Frank J.

1992-01-01

Discussed here is failure physics, the study of how products, hardware, software, and systems fail and what can be done about it. The intent is to impart useful information, to extend the limits of production capability, and to assist in achieving low cost reliable products. A review of reliability for the years 1940 to 2000 is given. Next, a review of mathematics is given as well as a description of what elements contribute to product failures. Basic reliability theory and the disciplines that allow us to control and eliminate failures are elucidated.

Networked Cultures in the Collaborative Economy

DEFF Research Database (Denmark)

Gyimóthy, Szilvia

2017-01-01

, and together open up for multidimensional interpretations of social exchange in the collaborative economy. The chapter concludes with a critical reflection on the challenges of understanding the collaborative economy in tourism, particularly when discourses are dominated by a communitarian logic......This chapter charts diverse approaches to conceptualizing the cultures of connection characterizing the collaborative economy. To decode the “we-conomy”, we revisit classic notions of coexistence, collaboration and bonding in communities. Informed by a multidisciplinary review (touching upon human...... ecology, sociology, anthropology and cultural theory), the chapter identifies distinct theoretical frameworks to describe the constitution of communities and discusses their relevance to the collaborative economy. These frameworks explain the drivers of communitarian behavior and resource circulation...

Companies' human capital required for collaboration

DEFF Research Database (Denmark)

Albats, Ekaterina; Bogers, Marcel; Podmetina, Daria

building, relationship building, IPR management and negotiation for the context of collaboration with universities. Our research has revealed an importance of expectation management skills for university-industry collaboration (UIC) context. We found that human capital for UIC is to be continuously......Universities are widely acknowledged as an important source of knowledge for corporate innovation, and collaboration with universities plays an important role in companies’ open innovation strategy. However, little is known about the human capital components required for collaboration...... with universities. Analysing the results of the survey among over 500 company managers we define the universal employees’ skills required for company’ successful collaborations with external stakeholders. Then through analysing qualitative interviews data we distinguish between these skills and capabilities...

Describing and Enhancing Collaboration at the Computer

Directory of Open Access Journals (Sweden)

Ken Beatty

2002-06-01

Full Text Available Computer-based learning materials differ from classroom practice in that they seldom explicitly offer opportunities for collaboration. Despite this, students do collaborate, helping one another through the content and affordances of computer materials. But, in doing so, students meet with challenges. Paradoxically, these challenges can either inspire or discourage learning and second-language acquisition. This paper, based on research with twenty Hong Kong university students in a controlled experiment, evaluates challenges to collaboration at the computer as evidenced by discourse. The students were videotaped and their discourse transcribed and evaluated both qualitatively and quantitatively, according to a set of discourse markers created to describe collaborative, non-collaborative and ambiguous strategies. The paper begins by exploring the differences between collaboration and similar terms such as teamwork and cooperative learning then goes on to define collaboration in the context of computer-assisted learning. It ends by presenting practical suggestions for software designers, teachers and students to enhance collaboration at the computer.

Designing collaborative policy innovation

DEFF Research Database (Denmark)

Agger, Annika; Sørensen, Eva

2014-01-01

Recent approaches to enhancing public innovation suffer from two shortcomings: They overemphasize competition as a driver of innovation and overlook the fact that public sector innovation involves policy innovation as well as service innovation. Drawing on governance research and innovation theory......, the chapter investigates the extent to which and how collaboration between politicians and relevant stakeholders can spur the formulation, implementation and diffusion of new innovative policies. A case study of a process of collaborative policy innovation in a Danish municipality shows that collaborative...... policy arenas do contribute to policy innovation but also that the degree to which they do so depends on the institutional design of these arenas....

Sensemaking in collaborative networks

DEFF Research Database (Denmark)

Peronard, Jean-Paul; Brix, Jacob

2018-01-01

be redesigned to strengthen the collaboration between companies. To enable this discussion we delve into the sensemaking literature and theory from loosely coupled systems. Our discussion leads to the development of the Balanced Activity System (BAS) model. The paper’s key contribution is the prescriptive BAS......The purpose of the study is to advance research on open business models as activity systems (Zott and Amit, 2010) in collaborative networks. We utilize Bradley’s (1995) theory of exchange behavior to discuss how new joint activities can be explored as well as how existing activities can...... model that can be used strategically in collaborative networks to redesign or create new joint activities....

Collaboration in experiential therapy.

Science.gov (United States)

Berdondini, Lucia; Elliott, Robert; Shearer, Joan

2012-02-01

We offer a view of the nature and role of client-therapist collaboration in experiential psychotherapy, focusing on Gestalt and emotion-focused therapy (EFT). We distinguish between the necessary condition of mutual trust (the emotional bond between client and therapist) and effective collaboration (regarding the goals and tasks of therapy). Using a case study of experiential therapy for social anxiety, we illustrate how the development of collaboration can be both complex and pivotal for therapeutic success, and how it can involve client and therapist encountering one another through taking risks by openly and nonjudgementally disclosing difficult experiences in order to enrich and advance the work. © 2012 Wiley Periodicals, Inc.

Collaborative Knowledge Framework for Mediation Information System Engineering

Directory of Open Access Journals (Sweden)

Wenxin Mu

2017-01-01

Full Text Available With the worldwide interenterprise collaboration and interoperability background, automatic collaborative business process deduction is crucial and imperative researching subject. A methodology of deducing collaborative process is designed by collecting collaborative knowledge. Due to the complexity of deduction methodology, a collaborative knowledge framework is defined to organize abstract and concrete collaborative information. The collaborative knowledge framework contains three dimensions: elements, levels, and life cycle. To better define the framework, the relations in each dimension are explained in detail. They are (i relations among elements, which organize the gathering orders and methods of different collaborative elements, (ii relations among life cycle, which present modeling processes and agility management, and (iii relations among levels, which define relationships among different levels of collaborative processes: strategy, operation, and support. This paper aims to explain the collaborative knowledge framework and the relations inside.

A collaborative smartphone sensing platform for detecting and tracking hostile drones

Science.gov (United States)

Boddhu, Sanjay K.; McCartney, Matt; Ceccopieri, Oliver; Williams, Robert L.

2013-05-01

In recent years, not only United States Armed Services but other Law-enforcement agencies have shown increasing interest in employing drones for various surveillance and reconnaissance purposes. Further, recent advancements in autonomous drone control and navigation technology have tremendously increased the geographic extent of dronebased missions beyond the conventional line-of-sight coverage. Without any sophisticated requirement on data links to control them remotely (human-in-loop), drones are proving to be a reliable and effective means of securing personnel and soldiers operating in hostile environments. However, this autonomous breed of drones can potentially prove to be a significant threat when acquired by antisocial groups who wish to target property and life in urban settlements. To further escalate the issue, the standard detection techniques like RADARs, RF data link signature scanners, etc..., prove futile as the drones are smaller in size to evade successful detection by a RADAR based system in urban environment and being autonomous, have the capability of operating without a traceable active data link (RF). Hence, towards investigating possible practical solutions for the issue, the research team at AFRL's Tec^Edge Labs under SATE and YATE programs has developed a highly scalable, geographically distributable and easily deployable smartphone-based collaborative platform that can aid in detecting and tracking unidentified hostile drones. In its current state, this collaborative platform built on the paradigm of "Human-as-Sensors", consists primarily of an intelligent Smartphone application that leverages appropriate sensors on the device to capture a drone's attributes (flight direction, orientation, shape, color, etc..,) with real-time collaboration capabilities through a highly composable sensor cloud and an intelligent processing module (based on a Probabilistic model) that can estimate and predict the possible flight path of a hostile drone

Alpha Stable Distribution Based Morphological Filter for Bearing and Gear Fault Diagnosis in Nuclear Power Plant

Directory of Open Access Journals (Sweden)

Xinghui Zhang

2015-01-01

Full Text Available Gear and bearing play an important role as key components of rotating machinery power transmission systems in nuclear power plants. Their state conditions are very important for safety and normal operation of entire nuclear power plant. Vibration based condition monitoring is more complicated for the gear and bearing of planetary gearbox than those of fixed-axis gearbox. Many theoretical and engineering challenges in planetary gearbox fault diagnosis have not yet been resolved which are of great importance for nuclear power plants. A detailed vibration condition monitoring review of planetary gearbox used in nuclear power plants is conducted in this paper. A new fault diagnosis method of planetary gearbox gears is proposed. Bearing fault data, bearing simulation data, and gear fault data are used to test the new method. Signals preprocessed using dilation-erosion gradient filter and fast Fourier transform for fault information extraction. The length of structuring element (SE of dilation-erosion gradient filter is optimized by alpha stable distribution. Method experimental verification confirmed that parameter alpha is superior compared to kurtosis since it can reflect the form of entire signal and it cannot be influenced by noise similar to impulse.

Negotiating Collaborative Governance Designs

DEFF Research Database (Denmark)

Plotnikof, Mie

2017-01-01

This chapter addresses the design and implementation issues of collaborative governance, a public management practice aimed at involving stakeholders in problem-solving and public innovation.......This chapter addresses the design and implementation issues of collaborative governance, a public management practice aimed at involving stakeholders in problem-solving and public innovation....

Enhancing performance through collaboration

International Nuclear Information System (INIS)

Froats, J.

2010-01-01

This presentation examines how co-operation and collaboration are keys to high performing organizations and attempts to provoke some thinking about how one can improve the game to meet the challenges of today. The presentation discusses the origins of the belief system and gives examples of the benefits of collaborative approaches.

KNOWLEDGE MANAGEMENT AND COLLABORATION EFFECTS: SOUTH-SOUTH NGO COLLABORATION: A CASE STUDY ON THE BRAZILIAN INTERDISCIPLINARY AIDS ASSOCIATION

Directory of Open Access Journals (Sweden)

Grace Keeney

2012-06-01

Full Text Available In June 2008, the Brazilian Interdisciplinary AIDS Association (ABIA and the Indian NGO SAHARA submitted a joint pre-grant opposition to the patent application of Tenofovir Disoproxil Fumarate in India. This joint action provides a pertinent case model of the potential effects of South-South cooperation between civil society groups. In this study, the aim sought to determine the practicality of the methodology and propositions developed in Resources, Knowledge and Influence: the Organizational Effects of Interorganizational Collaboration (Hardy et al., 2003 in predicting the types of collaboration effects that would result from the degree of “involvement” and “embeddedness” of a collaboration. Data collection came from archival research, participant observation research and interviews. Research tasks included an investigation on South-South Cooperation in the area of IP rights and AIDS, compiling an SLR on knowledge management and collaboration theories, creating a chronology of the collaboration and application of aforementioned methodology. Application included (1 implementation of codification methodology based on “involvement” and “embeddedness” and (2 identification of types of effects in collaboration - strategic, knowledge creation or political. During data analysis, these effects were compared with the aims of collaboration. Results were then tested against propositions (Hardy et al., 2003 of the relationship between involvement and embeddedness and the collaborative effects. Findings support three propositions: (1 Collaborations with high levels of involvement will be positively associated with the acquisition of distinctive resources, (2 Collaborations with high levels of involvement and high levels of embeddedness will be positively associated with the creation of knowledge, (3 Collaborations that are highly embedded will be positively associated with an increase of influence.

Exploring perceptions of interprofessional collaboration in child mental health care

Directory of Open Access Journals (Sweden)

Atle Ødegård

2006-12-01

Full Text Available Purpose: This paper proposes a tentative theoretical model (PINCOM and a measure of mental health and school professionals' perception of interprofessional collaboration (IPC. Theory: The model is based on twelve constructs derived from a pilot study, organizational and social psychology. The main aim of the model is to capture central aspects of IPC. Method: A forty-eight item self-report questionnaire (PINCOM-Q was designed to explore professionals' perceptions of IPC. The sample (n=134 included professionals who worked in primary care, specialist services and in elementary schools. Exploratory factor analyses and reliability testing were conducted to reduce the large number of variables in the questionnaire. Results: Results indicate that central aspects of IPC in the context of service delivery and case work are: interprofessional climate, organizational culture, organizational aims, professional power, group leadership and motivation. Conclusion: Preliminary empirical testing of the questionnaire demonstrated that it is possible to measure perceptions of IPC, with reasonable levels of construct validity and reliability. Discussion: Further, revision of the questionnaire is discussed to make it fit for use in large scale studies with the purpose of enhancing (a the validity of the PINCOM model, and (b the quality of mental health services that are based on IPC.

A Prognostic Method for Fault Detection in Wind Turbine Drivetrains

DEFF Research Database (Denmark)

Nejada, Amir R.; Odgaard, Peter Fogh; Gao, Zhen

2014-01-01

In this paper, a prognostic method is presented for fault detection in gears and bearings in wind turbine drivetrains. This method is based on angular velocity measurements from the gearbox input shaft and the output to the generator, using two additional angular velocity sensors on the intermedi......In this paper, a prognostic method is presented for fault detection in gears and bearings in wind turbine drivetrains. This method is based on angular velocity measurements from the gearbox input shaft and the output to the generator, using two additional angular velocity sensors...... bearing faults in three locations: the high-speed shaft stage, the planetary stage and the intermediate-speed shaft stage. Simulations of the faulty and fault-free cases are performed on a gearbox model implemented in multibody dynamic simulation software. The global loads on the gearbox are obtained from...