• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.315-318
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• 2007

Non-Destructive Health Monitoring using PZT sensors is a major concern and has great significance for research about NDT (Non-Destructive Test). In this paper, we study about the guided wave measurement method using PZT sensors to find cracks and estimate locations. Two aluminum beams bonded with PZT sensors were tested for estimating about the guided wave propagation characteristics and shape of each beam are decided in terms of analytical purpose. NI Signal Acquisition Device and specially designed LabVIEW VI program were used for data acquisition and analysis. The measured data were progressed by using a high-pass filtering.

• Journal of KIISE:Databases
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• v.37 no.1
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• pp.22-32
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• 2010

Location-based services have been expanded rapidly in local and overseas markets due to technological advances and increasing applications of wireless internet. Various researches have been made to manage efficiently the location information of moving objects. A basic location-based alert service provides alerting messages automatically when either entering or leaving a specific location and it is expected to become one of the most important location-based services. Location-based alert services require a location polling method to acquire current locations for a large number of moving objects. However, a simple periodical location polling method causes severe system overload because a system should keep updating location information of the moving objects ceaselessly. Most location polling algorithms for location-based alerting services are not suitable for mobile users with dynamic and unsteady moving patterns. In this paper, we propose an improved location polling algorithm for location-based alerting services to reduce the amount of location information acquisition and therefore, to decrease the system load. Various experiments show that the proposed algorithm outperforms other algorithms.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.1
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• pp.70-79
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• 2017

This study proposes a method to quickly and accurately acquire distance information on direction signs. The proposed method is composed of the recognition of the sign, pre-processing to facilitate the acquisition of the road sign distance, and the acquisition of the distance data. The road sign recognition uses color detection including gamma correction in order to mitigate various noise issues. In order to facilitate the acquisition of distance data, this study applied tilt correction using linear factors, and resolution correction using Fourier transform. To acquire the distance data, morphological operation was used to highlight the area, along with labeling and template matching. By acquiring the distance information on the direction sign through such a processes, the proposed system can be output the distance remaining to the next junction. As a result, when the proposed method is applied to system it can process the data in real-time using the fast calculation speed, average speed was shown to be 0.46 second per frame, with accuracy of 0.65 in similarity value.

• Journal of Korean language education
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• v.28 no.4
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• pp.337-366
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• 2017

This study examines the acquisition of the multiple semantic functions of the Korean adverbial particle -ey by L1 American English learners of Korean as a second language at U.S. institutions. Participants at beginning, intermediate, and advanced proficiency levels (N = 45) were tested on the ability to interpret and produce five of the meanings of -ey, which they had been taught in formal classroom settings in the first semester of their Korean language learning. The results show different developmental trajectories for the particle's different semantic functions. The findings of a statistical analysis indicate that the beginning and intermediate proficiency learners had largely acquired the time, goal, and stative location meanings, but not the contact and unit meanings; the advanced learners demonstrated acquisition of all except for the unit meaning. The study suggests that in addition to factors such as semantic complexity and cross-linguistic influence, several other factors including L2 frequency, the availability of linguistic input, and instructional method also contribute to the acquisition of -ey.

• Journal of Aerospace System Engineering
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• v.13 no.2
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• pp.19-25
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• 2019

To detect the impact location of a structure, the authors' group conducted a study on piezoelectric paint sensor. The piezoelectric paint sensors are used for impact detection due to their inherent characteristics: sensitivity to high-frequency signal and impact. Additionally, the paint sensor can be applied on curved and complex structures where ceramic sensor would not be applicable. Moreover it is a self-powered sensor therefore no need for an external power source. For impact localization, mosaic pattern electrodes were coated on the specimen and the impact signal obtained from any part of the electrode where the impact occurred. If we more precise impact localization is required, the electrodes should be divided into more parts and impact data acquisition conducted in all the points of the electrode. In this paper, we developed a light, cheap and simple multi-channel data acquisition system to aid in data gathering. In total four channels data acquisition have been tested using the ARM Cortex-M3.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.3
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• pp.252-261
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• 1992

The accuracy of the position fixing with telemetry techniques depends in general on the accuracy of the location of the receiving point(hydrophone). To increase the accuracy of the coordinates of four hydrophones suspended down at both sides of the vessel anchored, each hydrophone motion is compensated using a depth pinger mounted on the seabed of 30m depth. The pinger location is calculated with a hyperbolic method. Using this technique so called hydrophone coordinates calibration, the movement of the Remotely Operated Vehicle(ROV), which has the same type of pinger mentioned above could be tracked down more accurately. Under the maximum variation ranges of a hydrophone of 5.2m in athwartships, 3.2m in alongship, and about 0.2m/s of the moving velocity in both directions, the ROV track with calibration is more close to the reality than that without calibration Tow depth pingers of same frequency can be distinguished by the use of three factors; The pulse period, the phase and the pulse period variation allowed in acquisition of the pinger as far as its pulse period is varied in smooth.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.17 no.1
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• pp.1-8
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• 2009

In this paper, reorientation based on angular momentum exchange is applied for a bias momentum stabilized satellite, which is equipped with a spherical fuel tank, and the effect of liquid slosh on the attitude properties such as inertia tensor and angular rate is investigated. In order to represent the slosh motion of liquid an equivalent mechanical model is adopted and full nonlinear equations of motion for three-body system are derived. Computer simulations are performed for several cases, which use the viscosity of liquid and the center location of the tank as input parameters, mainly in order to observe how the viscosity of liquid and the center location of the tank influence the spacecraft’s attitude. The investigation includes observing time-variations of the inertia tensor, especially presence of components of product of inertia during the maneuver.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.371-372
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• 2016

In this paper, the encoder of the hybrid type which can use a single position sensor in order to overcome the use of multiple signal lines and the reliability reduction for the location information acquisition caused by using a plurality of position detectors to acquire the position information of the rotor offer. Encoder of the proposed method was the replacement location information generating function by the plurality of sensors to the Capture function of the shape and the microcomputer of the encoder plate. Capture of the DSP function was verified through experiments using the in order to verify the validity of the detection by the proposed method and the hybrid encoder position prototyping, a means.

• Journal of Information Processing Systems
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• v.19 no.5
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• pp.576-589
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• 2023

To upgrade home style recommendations and user satisfaction, this paper proposes a personalized and optimized recommendation algorithm for interior design style based on local social network, which includes data acquisition by three-dimensional (3D) model, home-style feature definition, and style association mining. Through the analysis of user behaviors, the user interest model is established accordingly. Combined with the location-based social network of association rule mining algorithm, the association analysis of the 3D model dataset of interior design style is carried out, so as to get relevant home-style recommendations. The experimental results show that the proposed algorithm can complete effective analysis of 3D interior home style with the recommendation accuracy of 82% and the recommendation time of 1.1 minutes, which indicates excellent application effect.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.2
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• pp.171-176
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• 2013

X-ray cross-sectional image-based inspection technique is one of the most useful methods to inspect the brazing joints of heat exchanger. Through X-ray cross-sectional image acquisition, image processing, and defect inspection, the defects of brazing joints can be detected. This paper presents a method to judge the type of detected defects automatically, and to display them three-dimensionally. The defect type is classified as unconnected defect, void, and so on, based on location, size, and shape information of defect. Three-dimensional display which is realized using OpenGL (Open Graphics Library) will be helpful to understand the overall situation including location, size, shape of the defects in a test object.