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A study on using acoustic emission in rock slope with difficult ground – focused on rainfall
Yo-Seph Byun,Myung Sagong,Suk-Chun Kim,Byung Sik Chun,Seong-Yong Park,Hyuk-Sang Jung 한국지질과학협의회 2012 Geosciences Journal Vol.16 No.4
This study attempted to predict slope failures by applying AE techniques to a rock slope with a history of collapse. Damage levels were assessed on the basis of the AE characteristics estimated by conducting laboratory tests on simulated slope failures. The test results showed that the specimen showed a very high degree of failure at the initial stage of loading, which was analyzed using the AE characteristics to assess the damage levels. The variation in the measured number of AE hits and AE events in field tests may indicate minute variations in the slope. The measured values appeared to be insignificant as they were less than the minimum criterion for damage. An analysis of rainfall, which is an important factor in slope behavior, showed that as rainfall increased, the number of AE hits and AE events also increased. In particular, when the cumulative rainfall was constant, the cumulative number of AE hits and AE events appeared to converge, indicating that the cumulative rainfall and the number of AE hits are closely connected. When applying AE techniques to a slope that has a high probability of failure, the failure prediction of the specific location and the early prediction of failure behavior on rock slopes became possible.
양요셉(Yo Seph Yang),안성민(Seongmin Ahn),김성현(Seong Hyeon Kim),최동일(Dongil Choi) 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.11
Recently, as the service robot market has grown, robots have emerged in various fields such as industry, service, and sports. In the field of sports, robots that can play with humans such as Forpheus, Robomintoner, and Ldric have been developed. These robots can act as coaches by providing human race data as well as athletic events. We developed a vision system that detects balls and predicts trajectories to develop tennis sports robots. In this paper, we introduce ball detection artificial neural networks and ball trajectory prediction using stereo vision. As a result, the accuracy of the neural network for ball detection in actual tennis images reaches 81%. The ball trajectory prediction error in Gaz ebo simulation is 29.6 cm in the x-axis, 7.2 cm in the y-axis, and 11.7 cm in the z-axis on average.
Lee, Yo Seph,Lee, Han Bi,Koo, Hye Young,Choi, Won San American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.43
<P>Magnetic sponges (MSs) and magnetic threads with hydrophilic and hydrophobic characteristics that can perform remote-controlled oil/water separation in a confined space and anaerobic reactions were prepared. For large amounts of water or oil, trainlike hydrophilic or hydrophobic MSs composed of more than three sponge balls moved as a group and quickly absorbed the water or oil droplets in oil or water by magnetic manipulation from outside of the tube. For the removal of heavy oils below the water in three-liquid multiphase solutions, the hydrophobic MS balls were moved to the heavy oil below the water, absorbed some of the heavy oil, and returned to the light oil layer to deliver the heavy oil by means of an external magnetic field. The mixed oils floating on the water were easily removed by a suction pump once the heavy oil had been completely delivered to the light oil layer via the round-trip process. Furthermore, our approach was demonstrated for use in an anaerobic reaction system due to the strong magnetic property that transfers the reactants/products, the porous structure providing a reaction site, and the prewetting ability containing the reactants/products of the MSs and the oil layer prohibiting oxygen contact.</P> [FIG OMISSION]</BR>
변요셉 ( Yo Seph Byun ),김민기 ( Min Gi Kim ),박경한 ( Kyung Han Park ),오태근 ( Tae Keun Oh ),성주현 ( Joo Hyun Seong ) 한국안전학회(구 한국산업안전학회) 2016 한국안전학회지 Vol.31 No.2
Recently, the frequency and intensity of localized heavy rain and typhoon due to the abnormal climate has increased, and especially the damage by an avalanche of earth and rocks similar to the landslide of Umyeon Mountain has become a social issue. However, the standardized damage investigation method doesn’t yet exist, so the systematic analysis of the data has not been carried out. In this regard, this study developed assessment items to conduct standardized damage investigation of debris flow. To achieve this, preliminary assessment items were derived from analysis of literature review and the Delphi technique of 12 experts who are engaged in research facility, academia and industry was conducted. As a result, 29 assessment items which can be classified into 6 groups were determined. Surveying the relevant hand-on workers, details assessment items in each group were determined by exploratory factor analysis and reliability analysis.
멀티비전을 이용한 실시간 테니스 공 궤적 및 낙하지점 예측방법
양요셉(Yo Seph Yang),최동일(Dongil Choi) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
Recently, the development of robots that can exercise and play sports with humans is actively progressing. In sports such as tennis and table tennis, it is important to predict the trajectory of a moving ball to receive the ball. The problem of predicting the trajectory of a ball using robot camera images is a topic that is being actively studied in the field of computer vision. In this paper, we introduce a tennis ball trajectory prediction method using a multi-vision system. In order to predict the trajectory of the ball, the identification of the position and speed of the tennis ball must be prioritized. Our multi vision system sets up two cameras and estimates ball position and landing point in real-time through object detection. The performance of the proposed method was evaluated through Gazebo simulation. As a result of predicting landing points for 500 samples with a tennis ball speed of 65 to 90 km/h, the x-axis error MAE is 0.3 m, the RMSE is 0.406 m, the y-axis error MAE is 0.065 m, and the RMSE is 0.119 m.