• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1207-1210
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• 2004

As many humans age, degenerative lumbar spinal stenosis (DLSS) becomes a major cause of lower limb discomfort and disability. By surgical treatment method of DLSS, the existing surgical treatment methods using internal fixation have showed degeneration changes of an adjacent vertebrae and loss of lumbar spine lordosis-kyphosis due to eliminating a motion. For solving the problems of internal fixation, a novel interspinous spacer has been developed to treat DLSS by surgical treatment method. In this study, we evaluated the biomechanical effects of the interspinous spacer on the kinematics of the porcine lumbar spine before and after insertion of the implant. For this purpose, a device that is capable of measuring 3-D motions were built based on direct linear transformation (DLT) algorithm written with MATLAB program. Results showed that in extension, a change of the mean angle between the intact and the implanted specimens at L4-L5 was 1.87 degree difference and the implant reduced the extension range of motion of the L4-L5 (p＆lt;0.05). But the range of motion in flexion, axial rotation and lateral bending at the adjacent segments was not statistically affected by the implant. In conclusion, we thought that interspinous spacer may have remedical value for DLSS by flexing human lumbar spine.

• 대한기계학회논문집
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• 제10권1호
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• pp.102-109
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• 1986

본 연구에서는 앞의 여러 연구자들이 시도한 3차원 연쇄기구의 운동해석법을 비교 검토하고, 이중 기호방정식을 이용하여 3차원 연쇄기구의 운동해석을 일반화 하고져 한다. 또 품질향상, 대량생산(mass production) 및 생산가 절하를 위해 만족시키기 위해, 기본해석모델인2차원 연쇄기구에서 3차원연쇄기구로 정밀화 하면서, 가능한 모든 3차원 연쇄기구의 복잡화 되고 있는 현대 기계의 운동요구를 만족시키기 위해, 기본해석모델인 2차원 연쇄기구에서 3차원연쇄기구로 정밀화 하면서, 가능한 모든 3차원 연쇄기구의 운동을 해석 하기 위한 일반해석법을 개발하므로써 해석을 일반화 시키고, 그것을 컴퓨터로 시뮬레이션하여 운동해석을 신빙성있고 신속하게 수행토록 하며, 컴퓨터 결과를 실제모형 즉 구면 4-R 연쇄기구, R-S-S-R 기구 및 3C-R 기구등을 제작하여,실제결과와 비교 검토하므로써 개발된 일반운동해석법의 타당성을 실험적으로 입증 비교 검토하므로써 일반운동해석법의 타당성을 실험적으로 입증하려 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권8호
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• pp.3981-4004
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• 2019

This paper proposes a novel method for locating objects in real space from a single remote image and measuring actual distances between them by automatic detection and perspective transformation. The dimensions of the real space are known in advance. First, the corner points of the interested region are detected from an image using deep learning. Then, based on the corner points, the region of interest (ROI) is extracted and made proportional to real space by applying warp-perspective transformation. Finally, the objects are detected and mapped to the real-world location. Removing distortion from the image using camera calibration improves the accuracy in most of the cases. The deep learning framework Darknet is used for detection, and necessary modifications are made to integrate perspective transformation, camera calibration, un-distortion, etc. Experiments are performed with two types of cameras, one with barrel and the other with pincushion distortions. The results show that the difference between calculated distances and measured on real space with measurement tapes are very small; approximately 1 cm on an average. Furthermore, automatic corner detection allows the system to be used with any type of camera that has a fixed pose or in motion; using more points significantly enhances the accuracy of real-world mapping even without camera calibration. Perspective transformation also increases the object detection efficiency by making unified sizes of all objects.

• 한국운동역학회지
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• 제21권4호
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• pp.449-458
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• 2011

There are many functional methods for estimating the mean axis of rotation of a joint. However, it is still a controversial issue which method is superior. The purpose of this study was to compare functional methods for estimated axes of rotation from synthetic data. The comparison was made in terms of suitabilities on describing humans in sports. For a more practical situation, the axis error as well as measurement and marker movement error were applied to generated data. Simulations having 1000 times of 80 rotational displacements were performed. The functional methods used in the study were two transformation methods, two fitting methods, and one more transformation method called M. The M method is a combination of S$\ddot{o}$derk & Wedin(1993) and Mardia & Jupp(2000). Another factor of the study was angular velocity with levels of .01, .025, .05, .5 and 1 rad/s. The method M resulted in unbiased, stable, and consistent axis of rotation vectors in all levels of angular velocity except .01 rad/s. Therefore, the method M had the highest validity and reliability of all the methods. The fitting methods were very sensitive in small angular velocities and stable only in the velocities of more than .5 rad/s. The most suitable method for analyzing human motion by using marker photogrammetry is M.

• 제어로봇시스템학회논문지
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• 제15권11호
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• pp.1122-1129
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• 2009

Recently taping robot with smart recognition function have been studied in the coil manufacturing field. Due to the difficulty of 3D surface processing from the complicated working environment, it is not easy to accomplish smart tape attachment motion with non-contact sensor. To solve these problems the applicable surface recognition algorithm and a flexible sensing device has been recommended. In this research, the fusion method between 1D displacement and 3D laser scanner is applied for robust tape attachment about cold rolled coil. With these sensors we develop a two-step exploration and the smart algorithm for the awareness of non-aligned coil's information. In the proposed robot system for tape attachment, the problem is reduced to coil's radius searching with laser displacement sensor at first, and then position and orientation detection with 3D laser scanner. To get the movement at the robot's base frame, the hand-eye compensation between robot's end effector and sensing device should be also carried out respectively. In this paper, we examine the auto-coordinate transformation method in the calibration step for the real environment usage. From the experimental results, it was shown that the taping motion of robot had a robust under the non-aligned cold rolled coil.

• 대한기계학회논문집A
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• 제41권9호
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• pp.869-876
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• 2017

기계시스템을 제어한다든지 그 부재를 설계하기 위하여 그리고 구동기의 용량을 결정하는데 있어서 구동력이나 조인트반력을 해석하는 것이 필요하다. 본 논문은 주어진 시스템의 운동을 구현하는 다양한 형태의 구동조건에 따른 구동력(또는 토크)을 조인트좌표 공간에서 계산하는 알고리즘을 제시한다. 조인트좌표를 기구학적 시스템의 일반좌표로 사용하며 운동방정식과 구속조건의 가속도식은 속도변환법을 이용하여 직교좌표공간으로부터 조인트좌표공간으로 변환한다. 수치예제를 통하여 제시된 알고리즘의 유용성을 확인한다.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제14권5호
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• pp.522-526
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• 2008

본 논문에서는 일반적인 비디오의 모션을 만화와 같은 스타일로 자동으로 변환해주는 시스템을 제안한다. 이 시스템은 비디오의 물리적인 상황에 맞게 자연스러운 변형을 손쉽게 적용할 수 있는 새로운 비디오의 만화화 방법이다. 선택된 비디오 오브젝트의 운동량, 운동방향, 힘과 같은 물리적인 요인들을 분석하여 물리적으로 타당한 변형을 적용함으로써 자연스러운 효과를 적용한다는 것이 장점이다. 전통적인 애니메이션에서 사용하는 몇 가지 전형적인 디포메이션 시나리오를 구축하고 사용자가 손쉽게 원하는 효과를 선택하여 적용한다. 타이밍 컨트롤과 카툰 렌더링을 사용하여 최종적으로 역동적이고 만화 같은 비디오를 만들어 낸다.

• Geomechanics and Engineering
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• 제2권4호
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• pp.229-252
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• 2010

In this paper, Soil-Structure Interaction (SSI) effect is investigated using a new and integrated approach. Faster solution of time dependant differential equation of motion is achieved using numerical representation of wavelet theory while dynamic Infinite Elements (IFE) concept is utilized to effectively model the unbounded soil domain. Combination of the wavelet theory with IFE concept lead to a robust, efficient and integrated technique for the solution of complex problems. A direct method for soil-structure interaction analysis in a two dimensional medium is also presented in time domain using the frequency dependent transformation matrix. This matrix which represents the far field region is constructed by assembling stiffness matrices of the frequency dependant infinite elements. It maps the problem into the time domain where the equations of motion are to be solved. Accuracy of results obtained in this study is compared to those obtained by other SSI analysis techniques. It is shown that the solution procedure discussed in this paper is reliable, efficient and less time consuming as compared to other existing concepts and procedures.

• 융합신호처리학회논문지
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• 제7권4호
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• pp.155-160
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• 2006

본 논문에서는 웨이브릿 변환 영역의 4개의 서브밴드와 임계값 처리를 이용하는 계층적 블록 매칭 알고리즘을 제안하였다. 제안한 알고리즘은 다분해능의 첫 번째 레벨에서 웨이브릿 변환 영역의 4개 서브밴드를 이용함으로써 복원된 영상의 PSNR 성능을 향상시켰고, 움직임 벡터에 대한 임계값 처리를 하여 계산량을 줄였다. Carphone 영상과 Mother and Daughter 영상에 대한 실험에서 기존의 계층적 움직임 추정 알고리즘과 비교하여 임계값을 0으로 하였을 경우에 계산량은 최대 16%까지 증가하였으나 복원된 영상의 PSNR 성능은 최대 0.16dB 정도 향상된 결과를 보였고, 임계값을 증가시킴에 따라서 계산량은 최대 8%정도 줄고 복원된 영상의 PSNR은 비슷한 성능을 보였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권4호
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• pp.2042-2059
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• 2019

Digital shadow puppet has traditionally relied on expensive motion capture equipments and complex design. In this paper, a low-cost driven technique is presented, that captures human pose estimation data with simple camera from real scenarios, and use them to drive virtual Chinese shadow play in a 2.5D scene. We propose a special method for extracting human pose data for driving virtual Chinese shadow play, which is called 2.5D human pose estimation. Firstly, we use the 3D human pose estimation method to obtain the initial data. In the process of the following transformation, we treat the depth feature as an implicit feature, and map body joints to the range of constraints. We call the obtain pose data as 2.5D pose data. However, the 2.5D pose data can not better control the shadow puppet directly, due to the difference in motion pattern and composition structure between real pose and shadow puppet. To this end, the 2.5D pose data transformation is carried out in the implicit pose mapping space based on self-network and the final 2.5D pose expression data is produced for animating shadow puppets. Experimental results have demonstrated the effectiveness of our new method.