• Journal of the Korean Solar Energy Society
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• v.37 no.5
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• pp.1-11
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• 2017

A study on Nacelle Lidar (Light detection and ranging) measurement error and the data reliability verification was carried out at Haengwon wind farm on Jeju Island. For measurement data error processing, the characteristics of Nacelle Lidar measurements were analyzed by dividing into three parts, which are weather conditions (temperature, humidity, atmosphere, amount of precipitation), mechanical movement (rotation of wind turbine blades, tilt variation of Nacelle Lidar) and Nacelle Lidar data availability. After processing the measurement error, the reliability of Nacelle Lidar data was assessed by comparing with wind data by an anemometer on a met mast, which is located at a distance of 200m from the wind turbine with Nacelle Lidar. As a result, various weather conditions and mechanical movement did not disturb reliable data measurement. Nacelle Lidar data with availability of 95% or more could be used for checking Nacelle Lidar wind data reliability. The reliability of Nacelle Lidar data was very high with regression coefficient of 98% and coefficient of determination of 97%.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.181-184
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• 2002

In this paper, an algorithm is proposed for the automatic movement of the platform on a ladder lift which operates by using hydraulic force. Experimental data of the manual movement operated by experts are acquired and analyzed. The length of movement of the platform is estimated by the number of pulses from an encoder while the platform is moving. The operating characteristics have been extracted from the data. The number of pulses varies whenever the weight of load varies. We propose a model to compensate the difference of the number of pulses. An automatic movement algorithm based on the model is proposed. The platform can start and stop smoothly at the starting point and the destination point. Experimental results show that the error distance at the destination point is less than 5 cm when the length of the ladder is 23 m.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.2
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• pp.65-67
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• 2006

To make the autonomous mobile robot move in the unknown space, we have to know the information of current location of the robot. So far, the location information that was obtained using Encoder always includes Dead Reckoning Error, which is accumulated continuously and gets bigger as the distance of movement increases. In this paper, we analyse the effect of the size of the two wheels of the mobile robot and the wheel track of them among the factors of Dead Reckoning Error. And after this, we compensate this Dead Reckoning Error by Kalman filter using Gyro Sensors. To accomplish this, we develop the controller to analyse the error components of Gyro Sensor and to minimize the error values. We employ the numerical approach to analyse the error components by linearizing them because each error component is nonlinear. And we compare the improved result through simulation.

• Proceedings of the IEEK Conference
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• 2000.11d
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• pp.109-112
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• 2000

Bitstrems corrupted by channel errors are not only difficult to be decoded but also propagate error to other part of the bitstreams when highly compressed video is transmitted over channels with noise such as mobile communication channels. In this paper, error concealment algorithm performed in decoder is proposed when errors occur for transmission. Proposed algorithm searches moving area with homogeneous movement in neighbored blocks when motion vectors are damaged, then recovers motion vectors of missing blocks considering where missing blocks are belong to. Experiment result shows that proposed algorithm exhibits better performance in PSNR than existing error concealment method.

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.95-103
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• 2006

The purpose of this study was to review the relevant literature about coaching and thereupon, survey the coaching methods used for golf lesson to reinterpret them and thereby, describe in view of kinetics the swing errors committed frequently by amateur golfers and suggest more scientific golf coaching methods. For this purpose, kinetic elements were divided into accuracy and power ones and therewith, the variables affecting such elements were identified. For this study, a total of 60 amateur golfer were sampled, and their swing forms were photographed with two high-speed digital cameras, and the resultant images were analyzed to determine the errors of each form kinetically, which would be analyzed again with the program V1-5000. The kinetic elements could be identified as accuracy, power and accuracy & power. Thus, setup and trajectory were classified into accuracy elements, while differences of inter-joint angles, cocking and delayed hitting. Lastly, timing and axial movement were classified into accuracy & power elements. Three errors were identified in association with setup. The errors related with trajectory elements accounted for most (6) of the 20 errors. Three errors were determined for inter-joint angle differences, and one error was associated with cocking and delayed hitting. Lastly, one error was classified into timing error, while five errors were associated with axial movement. Finally, as a result of arranging the errors into a cross table, it was found that the errors were associated with each other between take-back and back-swing, take-back and follow-through, back-swing and back-swing top, and between back-swing and down-swing. Namely, an error would lead to other error repeatedly. So, it is more effective to identify all the errors for every form and correct them comprehensively rather than single out the errors and correct them one by one.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.6
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• pp.745-751
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• 2013

In naval gun firing, firing accuracy comes from the combination of each component's accuracy in CFCS (Command and Fire Control System) like tracking sensors and gun. Generally, battery alignment is done to correct the error between gun and tracking sensor by using boresight telescope on harbor and sea. But normally, the battery alignment can compensate only the static alignment error and ignore dynamic alignment error which is caused by own ship movement. There was no research on this dynamic alignment error until now. We propose a new way to analyze dynamic arrangement error by using image of boresight telescope. In case of the dynamic alignment error was due to time delay of own ship attitude information, we propose the way to compensate it.

• IEMEK Journal of Embedded Systems and Applications
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• v.11 no.3
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• pp.183-191
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• 2016

Recently, in rehabilitation treatment, the situation that requires a measure of the accuracy of the pose and movement of joints is being increased due to the habits and lifestyle of modern people and the environment. In particular, there is a need for active automated system that can determine itself for the matching rate of pose Basically, a method for measuring the matching rate of pose is used by extracting an image using the Kinect or extracting a silhouette using the imaging device. However, in the case of extracting a silhouette, it is difficult to set the comparison, and in the case of using the Kinect sensor, there is a disadvantages that high accumulated error rate according to movement. Therefore, In this paper, we propose a method to reduce the accumulated error of matching rate of pose getting the rotation angle of joint by measuring the real-time amount of change of 9-axis sensor. In particular, it can be measured same conditions that unrelated of the physical condition and unaffected by the data for the back and forth movement, because of it compares the current rotation angle of the joint. Finally, we show a comparative advantage results by compared with traditional method of extracting a silhouette and a method using a Kinect sensor.

• PNF and Movement
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• v.8 no.1
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• pp.67-77
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• 2010

Purpose : The purpose of this study was to investigate the usefulness of clinical balance tests through the correlation of balance evaluation using by forceplate in elderly. Methods : Thirty nine healthy elderly subjects (14 males, 25 females) participated in the study. The subjects were evaluated with clinical balance tests [(Berg balance scale (BBS), Functional reach test (FRT), Tinetti's performance oriented mobility assessment (POMA), and one leg standing (OLS)]. Static balance evaluation was assessed by using forceplate. Center of pressure (COP) parameters were obtained using it as total path distance, total sway area, X mean frequency and Y mean frequency for 20 seconds in the following conditions: (1) comfortable standing with eyes opened and closed, (2) uncomfortable standing with eyes opened and closed. After static balance evaluation tested, dynamic balance evaluation was assessed. COP parameters were error distance and area during sine curve trace. COP parameters were movement time, error distance, and maintained time in the circle during COP movement task. Results : Clinical balance tests showed statistically significant correlation between static and dynamic balance evaluations. Among the clinical balance tests, the BBS, POMA, and OLS showed significant correlation with to assess the balance ability of elderly in clinical setting both evaluations. Conclusion : Clinical balance tests can be recommended in clinical setting because of low costs and simplicity.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.9
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• pp.1051-1059
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• 1992

In this paper, two general methods using time-series analysis in the functional separation of the myoelectric signal of human arm movements are developed. Autocorrelation, covariance method and sequential least squares algorithm were used to determine the model parameters and the order of signal model to describe six arm movement patterns` the forearm flexion and extension, the wrist pronation and supination, rotation-in and rotation-out. The confidence interval to classify the functions of arm movement was defined by the mean and standard deviation of total squared error. With the error signals of autoregressive(AR) model, the result showed that the highest success rate was obtained in the case of 4th order, and success rate was decreased with increase of order. Autocorrelation was the method of choice for better success rate. This technique might be applied to biomedical and rehabilitation engineering.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.140-145
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• 2002

In high-capacity disk drives with ever-growing track density, the allowable level of position error signal (PES) is becoming smaller and smaller. A substantial portion of the PES is caused by disk vibration. This can be reduced by using a head gimbal assemblies (HGAs) that do not confine the slider movement to the vertical direction to disks, but allow movement to the radial direction of disks with respect to disk vibration. Several types of HGAs are proposed for such radial motion of the slider. Experimental results show that the PES levels are reduced by the proposed HGA-design concepts.