• New & Renewable Energy
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• v.16 no.1
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• pp.25-30
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• 2020

In this study, an SW for the analysis of the wind-turbine vibration characteristics was developed as an application of SaaS cloud infrastructure. A measurement system for power-performance, mechanical load, and gearbox vibration as type-test class was installed at a target MW-class wind turbine, and structural meta and raw data were then acquired into the cloud. Data processing algorithms were developed to provide cloud data to the SW. To operate the SW continuously, raw data was downloaded consistently based on the algorithms. During the SW test, an intermittent long time-delay occurred due to the communication load associated with frequent access to the cloud. To solve this, a compression service for the target raw data was developed in the cloud and more stable data processing was confirmed. Using the compression service, stable big data processing of wind turbines, including gearbox vibration analysis, is expected.

• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1615-1625
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• 2013

Modelling and simulating the wind power intermittent behaviour are the basis of the planning and scheduling studies concerning wind power integration. The wind power outputs are evidently correlated in space and time and bring challenges in characterizing their behaviour. This paper provides a methodology to model and simulate the clustered wind power considering its spatio-temporal correlations using the theory of copula. The sampling approach captures the complex spatio-temporal connections among the wind farms by employing a conditional density function calculated using multidimensional copula function. The empirical study of real wind power measurement shows how the wind power outputs are correlated and how these correlations affect the overall uncertainty of clustered wind power output. The case study validates the simulation technique by comparing the simulated results with the real measurements.

• Korean Journal of Adult Nursing
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• v.19 no.5
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• pp.127-137
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• 2007

Purpose: It was investigated if abdominal meridian massage has effects on constipation in institutionalized psychiatric patients taking antipsychotic drugs. Methods: According to the constipation screening tests, 22 patients were selected as subjects. One group pre and post repeated measurement design was used. Constipation was operationalized as perceived constipation, frequency of defecation, frequency of bowel sound, and number of medicine taken to relieve constipation. Abdominal meridian massage was given for two weeks, 10-15 minutes each time and 10 times in total. Results: Perceived constipation, frequency of bowel sound, and number of medicine taken were significantly improved after massage. Except for number of medicine taken, the effects on perceived constipation and frequency of bowel sound were found to be persistent 2 weeks after massage. Conclusion: Based upon these results, abdominal meridian massage was recommended as independent nursing intervention for the relief of constipation in psychiatric patients who taking anti-psychotic drugs. Further studies to investigate the maximal duration time of effects and whether the effects of intermittent application of this method is more beneficial than the continuous application of this method are necessary.

• Journal of ILASS-Korea
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• v.7 no.1
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• pp.14-20
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• 2002

It is well known that the flow and spray characteristics is critical factor on the performance and emission of a direct injection diesel engine. So this study aims to investigate the interaction of flow and spray characteristics. At first, in cylinder flow distributions in swirl adaptor for 4-valve cylinder head of DI Diesel engine were investigated under steady conditions for different SCV angles mounted on the cylinder head with steady rig test and 2-D LDV. And the in-cylinder flow was quantified in terms of mean flow coefficient and swirl ratio/tumble ratio. It was found that the swirl ratio is controlled between 2.3 and 3.8. Then spray characteristics of the intermittent injection were investigated. PDA system was utilized for measurement of a droplet size and velocity. The analyses of the PDA results are carried out with Time Dividing Method. It was found that there is a correlation between the swirl flow and SMD. The droplet size and the velocity were nearly constant value with each SCV angle. And the swirl ratio is higher, SMD smaller. The swirl ratio was helpful factor to the atomization of droplet.

• Journal of Biomedical Engineering Research
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• v.31 no.4
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• pp.275-279
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• 2010

The purpose of this study was to quantify the clinical assessment of rigidity at wrist in patients with Parkinson's disease. The experimental system was designed that the effect of gravity was negated by restricting motion at the horizontal plane and inertia was predetermined from a biomechanical measurement. Forty five patients with Parkinson's disease participated in this study. Viscoelastic properties were calculated from the experimental data acquired during intermittent passive movement of wrist. Viscoelastic constants correlated well with the rigidity scores of UPDRS, i.e., Spearman's r=0.733 and 0.905 for spring and damping constants, respectively. The results suggest that viscoelastic properties can be used as quantitative measures of rigidity.

• Journal of Korea Society of Digital Industry and Information Management
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• v.15 no.4
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• pp.19-29
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• 2019

Recently, with the rise of environmental issues and the change of government policy (Renewable Energy 3020 Implementation Plan), a large amount of renewable energy such as solar and wind power is connected to the power system, and most of the renewable energy is concentrated in the power distribution network. This causes many problems with the voltage management and the protection coordination of the grid due to the its intermittent power generation. In order to effectively operate the distribution network, it is necessary to deploy more intelligent terminal devices in the field to measure the status of the distribution network and develop various operation functions such as visualization and big data analysis to support the power distribution system operators. In addition, the failover technology must be supported for the non-stop operation of the power distribution system. This paper proposes the system architecture of new power distribution management system to cope with high penetration of renewable energy. To verify the proposed system architecture, the functional unit test and performance measurement were performed.

• Clinical and Experimental Pediatrics
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• v.46 no.9
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• pp.921-925
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• 2003

Intestinal lymphangiectasia, one of the protein-losing gastroenteropathies, is an uncommon disease characterized by dilated intestinal lymphatics, enteric protein loss, edema, hypoalbuminemia, and lympocytopenia. Small bowel biopsy and CT have been used to confirm the diagnosis of intestinal lymphangiectasia. Small bowel biopsy shows collections of abnormal dilated lacteals in submucosa with distortion of villi and CT findings have been described as diffuse nodular thickening of the small bowel and as linear hypodense streaking densities in the small bowel caused by dilated lymphatic channels. Demonstration of increased enteric protein loss using $^{51}Cr-$, $^{131}I-$ or $^{99m}Tc-labeled$ albumin, timed measurement of fecal excretion of radioactivity or by measuring fecal clearance of alpha 1-antitrypsin can also help the diagnosis. We experienced a rare case of intestinal lymphangiectasia in an eight year old boy who presented with facial edema, abdominal distension and intermittent diarrhea. We report a patient with intestinal lymphangiectasia, in whom abdominal CT, $^{99m}Tc-labeled$ albumin scintitigraphy, and stool alpha 1-antitrypsin measurement played key roles in determining the diagnosis. A brief review of literature was made.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.7
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• pp.637-648
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• 2007

This paper presents a sensor fusion method based on indirect Kalman filter(IKF) for error compensation of low-cost inertial sensors and its application to the determination of attitude and position of small flying robots. First, the analysis of the measurement error characteristics to zero input is performed, focusing on the bias due to the temperature variation, to derive a simple nonlinear bias model of low-cost inertial sensors. Moreover, from the experimental results that the coefficients of this bias model possess non-deterministic (stochastic) uncertainties, the bias of low-cost inertial sensors is characterized as consisting of both deterministic and stochastic bias terms. Then, IKF is derived to improve long term stability dominated by the stochastic bias error, fusing low-cost inertial sensor measurements compensated by the deterministic bias model with non-inertial sensor measurement. In addition, in case of using intermittent non-inertial sensor measurements due to the unreliable data link, the upper and lower bounds of the state estimation error covariance matrix of discrete-time IKF are analyzed by solving stochastic algebraic Riccati equation and it is shown that they are dependant on the throughput of the data link and sampling period. To evaluate the performance of proposed method, experimental results of IKF for the attitude determination of a small flying robot are presented in comparison with that of extended Kaman filter which compensates only deterministic bias error model.

• Journal of Oral Medicine and Pain
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• v.38 no.1
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• pp.29-34
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• 2013

Objective: All patients who have the disc displacement with reduction (DDwR) are always not progressive but some of them with significant catching or locking progress to disc displacement without reduction (DDw/oR). In this study, we suggest opening exercise therapy using Locking-free Appliance (LA) to be helpful to prevent progressive derangement. Methods: Retrospectively, a total 37 patients who received exercise treatment using LA was analyzed from January 2010 to December 2011. Patients had been instructed in proper exercise technique to practise for opening and closing of mouth wearing the appliance 30 times a day in locking-free position. Results: None of the patients took a turn for worse to DDw/oR (37 patients). The 16 patients (43.2%, locking-free group) of them could open their mouth without intermittent condylar locking. Measurement of data was analyzed using and Mann-Whitney test. There was no statistically significant difference for age, gender, presence of palpational pain, locking period, VAS quantitative pain score between locking-free group and locking group. Conclusions: In this study, some patients could open their mouth without intermittent locking and did not take a turn for worse to DDw/oR after opening exercise therapy with LA. Furthermore, LA had advantages which were short wearing time, low costs and minimizing patients' uncomfortable compared to conventional treatment method. This therapy can be more appropriate new treatment to prevent progress to DDw/oR.

• The Journal of the Acoustical Society of Korea
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• v.9 no.2
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• pp.42-52
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• 1990

A method of measuring impulse response of acoustic system, two kinds of cross-correlation methods (the direct correlation method and the M-sequence modulation correlation method) were applied. According to the direct correlation method, by using stationary random noise source and by calculating the cross-correlation function between the sourece and the output signal, equivalent impulse response can be obtained not being influenced by the back ground noises. By applying this method, the measurement of echo-time patterns in rooms and oblique incident sound absorption characteristics of sound absorbing materials was carried out. In the case of the M-sequence modulation correlation method which was contrived by Aoshima, an intermittent random nosie modulated by M-sequence signal is used as the source signal, and the cross-correlation function between the M-sequence signal and the squared output signal is calculated. According to this method, equivalent energy impulse response (squared impulse response) of te propagation system can be obtained without being influenced by the back ground noises and the air fluctuation caused by wind. As the applcaition of this measuring method to the architectural acoustics, the meaurements of echo-time patterns, reverberation decays and sound pressure lev디 distributions in rooms and sound insulation efficiencies in buildings were carried out. From these experimental studies, it has been found that this M-sequence modulation correlation method is markedly useful especially for the field masurement of sound insulation under high back ground noise condition.