• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.214-221
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• 2002

This study introduces a method to generate artificial earthquakes in Korean Peninsular using historical earthquake catalogues and point source model. For this purpose, three earthquake catalogues compiled by different researchers are compared to each other. And epicenters and magnitudes of future earthquakes are generated based on those catalogues. In generating ground motion accelertation, point source model proposed by Boore and Atkinson was adopted. Parameters of the model for South-Eastern part of Korean Peninsular was proposed by Noh and kn. From the epicenters, magnitudes, and ground motion models, possible earthquakes for 50,000 years are generated. Using these generated earthquakes ground accelrations and uniform hazard response spectra (UHRS) having 2%, 5%, and 10% exceedance probability in 50 years are proposed.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.1
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• pp.187-194
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• 2012

This paper compares two collision avoidance algorithms using a simulator. The collision avoidance is vital for autonomous navigation of a mobile robot. Artificial potential field method and elastic force method are major approaches for the collision avoidance. The two algorithms are compared in the respect of the time for motion completion and the length of the motion path. The simulator is developed based on IPC(Inter Process Communication) and a differential drive mobile robot is used for the comparison.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.8
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• pp.1014-1021
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• 1999

PID controllers with constant gains have been widely used in various control systems. But it is difficult to have uniformly good control performance in all operating conditions. In this paper, we propose a variable PID controller for robot manipulators. We divide total workspace of manipulators into several subspaces. PID controllers in each subspace are optimized using evolution strategy which is a kind of global search algorithm. In real operation, the desired trajectories may cross several subspaces and we select the corresponding gains in each subspace. The gains may have large difference on the boundary of subspaces, which may cause oscillatory motion. So we use artificial neural network to have continuous smooth gain curves to reduce the oscillatory motion. From the experimental results, although the proposed variable PID controller for robots should pay for some computational burden, we have found that the controller is more superior to the conventional constant gain PID controller.

• Structural Engineering and Mechanics
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• v.23 no.3
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• pp.233-247
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• 2006

Most codes of practice state that for large in-plane structures it is necessary to account for the spatial variability of earthquake ground motion. There are essentially three effects that contribute for this variation: (i) wave passage effect, due to finite propagation velocity; (ii) incoherence effect, due to differences in superposition of waves; and (iii) the local site amplification due to spatial variation in geological conditions. This paper discusses the procedures to be undertaken in the time domain analysis of a cable-stayed bridge under spatial variability of earthquake ground motion. The artificial synthesis of correlated displacements series that simulate the earthquake load is discussed first. Next, it is described the 3D model of the International Guadiana Bridge used for running tests with seismic analysis. A comparison of the effects produced by seismic waves with different apparent propagation velocities and different geological conditions is undertaken. The results in this study show that the differences between the analysis with and without spatial variability of earthquake ground motion can be important for some displacements and internal forces, especially those influenced by symmetric modes.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.6
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• pp.519-528
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• 2004

For reappearance of driving perception in a driving simulator, a washout algorithm is required. This algorithm can reappear the vehicle driving motions within workspace of the driving simulator. However classical washout algorithm contains several problems such as selection of order, cut-off frequency of filters, generation of wrong motion cues by characteristics of filters, etc. In order to overcome these problems, this paper proposes a new washout algorithm which gives more accurate sensations to drivers. The algorithm consists of an artificial inclination of the motion plate and human perception model with band pass filter and dead zone. As a result of this study, the motion of a real car could be reappeared satisfactorily in the driving simulator and the workspace of motion plate is restrained without scaling factor.

• Structural Engineering and Mechanics
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• v.41 no.5
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• pp.633-644
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• 2012

The paper presents the motion editor for the robotic movement in the study. The Motion Editor can edit all motions which we want to need. This method is easy when the beginners edit to motions of robots. And let them have interesting in robot control. This paper proposes two methods to edit movements. First, we edit the robot's movement in VB environment, and then we use the Motion Editor to make it. Finally, we compared merit and defect with two methods. Indeed, it is convenient when we use the Motion Editor.

• Structural Engineering and Mechanics
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• v.69 no.2
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• pp.177-191
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• 2019

The local topography has a significant effect on the characteristics of seismic ground motion. This paper investigates the influence of topographic effects on the seismic response of a train-bridge system. A 3-D finite element model with local absorbing boundary conditions is established for the local site. The time histories of seismic ground motion are converted into equivalent loads on the artificial boundary, to obtain the seismic input at the bridge supports. The analysis of the train-bridge system subjected to multi-support seismic excitations is performed, by applying the displacement time histories of the seismic ground motion to the bridge supports. In a case study considering a bridge with a span of 466 m crossing a valley, the seismic response of the train-bridge system is analyzed. The results show that the local topography and the incident angle of seismic waves have a significant effect on the seismic response of the train-bridge system. Leaving these effects out of consideration may lead to unsafe analysis results.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09a
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• pp.499-500
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• 2005

• Electronics and Telecommunications Trends
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• v.35 no.3
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• pp.1-8
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• 2020

Artificial-intelligence (AI) technology is used in a variety of fields, from robot cleaner motion control to call center counselors, AI speakers, and Mars exploration. Because the technology levels of all applications and services that utilize AI vary widely, it is not possible to view all applications using AI technology at the same level. Nevertheless, there have been no cases in which the level of AI technology was defined. Therefore, the Electronics and Telecommunications Research Institute (ETRI) Artificial Intelligence Research Laboratory has defined the levels of the main technical elements of AI from steps 1 to 6. In this report, the Artificial Intelligence Technology Level 1.0 (ATL 1.0) is presented. It was established by comprehensively referring to the AI technology prospects and technology roadmaps of major countries. It is hoped that it can be used as a measure for determining the levels of AI applications or services or as an indicator for establishing a technology roadmap.

• Journal of the Korea Society of Computer and Information
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• v.28 no.1
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• pp.39-47
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• 2023

In this paper, we propose a method to measure the similarity between golf swings in videos. As it is known that deep learning-based artificial intelligence technology is effective in the field of computer vision, attempts to utilize artificial intelligence in video-based sports data analysis are increasing. In this study, the joint coordinates of a person in a golf swing video were obtained using a deep learning-based pose estimation model, and based on this, the similarity of each swing segment was measured. For the evaluation of the proposed method, driver swing videos from the GolfDB dataset were used. As a result of measuring swing similarity by pairing swing videos of a total of 36 players, 26 players evaluated that their other swing sequence was the most similar, and the average ranking of similarity was confirmed to be about 5th. This ensured that the similarity could be measured in detail even when the motion was performed similarly.