• 한국해양공학회지
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• 제18권1호
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• pp.7-9
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• 2004

Using the solution to th contour integral of the complex logarithmic function ${\oint}_cIn(z-z_{0})dz$, the following definite integral, derived from the formula to calculate the forces exerted to n circular cylinder by the discrete vortices shed from it, has been evaluated (equation omitted)

• 방송공학회논문지
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• 제2권2호
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• pp.156-169
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• 1997

본 논문에서는 형태학적 연산(morphological operation)과 영역 융합(region merging) 방법을 이용한 영상 분할(image segmentation) 방법을 제안한다. 이를 위해서 형태학적 필터(morphological filter)를 이용하여 단순화한 영상에 대해, 다중크기 경사(multiscale gradient) 연산자를 이용하여 경사 영상(gradient image)을 얻는다. 경사 영상에 watershed 변환을 적용하면 분할 영상을 얻을 수 있는데, 이렇게 얻은 분할 영상은 대개 과분할(oversegmentation) 영상이므로, 분할 영역을 줄이기 위해 미소 영역(small region)이나 비슷한 특성을 갖는 인접 영역들은 서로 융합시킬 필요가 있다. 본 논문에서는 영역을 융합하기 위한 기준으로서 영역간의 평균 에지 강도와 각 영역의 화소값들에 비해 평균값을 사용하는데, 이러한 융합 기준은 contour following 과정에서 계산된다. 제안한 방법은 watershed 알고리듬, 영역에 기반한 영상 분할, 경계에 기반한 분할 방법을 결합한 방법으로서, 향상된 영상 분할이 가능함을 실험을 통하여 제시하였다.

• 전자공학회논문지S
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• 제35S권1호
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• pp.114-121
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• 1998

In this paper, we introudce the notion of the smoothly perfect 8-conntected (SP8C) contour and describe a coding technique for the SP8C contours. Based on the simplificationusing the majority filter proposed by Gu, SP8C contours are restricted on the contour lattice from the segmented image. By noting thating SP8C contours are restricted to travel in only 3 different directions along the contours, we attempt to encode the SP8C contours using the following two techniques. The one is the neighbouring direction segmentcoding, while the other is to employ the notion of the entropy endoding. Computer simulations reveal that the contours can be efficiently encoded by the two technique.

• 대한의용생체공학회:의공학회지
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• 제15권2호
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• pp.201-208
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• 1994

Many three-dimensional object modeling and display methods for computer graphics and computer vision have been developed. Recently, with the help of medical imaging devices such as computerized tomography, magnetic resonance image, etc., some of those object modeling and display methods have been widely used for capturing the shape, structure and other properties of real objects in many medical applications. In this paper, we propose the reconstruction and display method of the three-dimensional object from a series of the cross sectonal image. It is implemented by using the automatic threshold selection method and the contour following algorithm. The combination of curvature and distance, we select feature points. Those feature points are the candidates for the tiling method. As a results, it is proven that this proposed method is very effective and useful in the comprehension of the object's structure. Without the technician's responce, it can be automated.

• International journal of advanced smart convergence
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• 제12권4호
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• pp.134-141
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• 2023

We present a novel method aimed at refining ground truth data through regularization and modification, particularly applicable when working with the original ground truth set. Enhancing the performance of deep neural networks is achieved by applying regularization techniques to the existing ground truth data. In many machine learning tasks requiring pixel-level segmentation sets, accurately delineating objects is vital. However, it proves challenging for thin and elongated objects such as blood vessels in X-ray coronary angiography, often resulting in inconsistent generation of ground truth data. This method involves an analysis of the quality of training set pairs - comprising images and ground truth data - to automatically regulate and modify the boundaries of ground truth segmentation. Employing the active contour model and a recursive ground truth generation approach results in stable and precisely defined boundary contours. Following the regularization and adjustment of the ground truth set, there is a substantial improvement in the performance of deep neural networks.

• 대한전자공학회논문지SP
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• 제44권5호
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• pp.64-72
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• 2007

본 논문에서는 능동윤곽모델에 기반을 둔 스네이크 알고리듬을 움직임 추정과 결합하여 안정적인 객체 추적 기술을 제안하였다. 초기 영상에서 목표 객체의 초기 윤곽을 지정한 후 스네이크 알고리듬을 사용하여 객체의 경계 영역을 찾아내고, 동시에 움직임 추정 기술을 사용하여 객체의 이동 방향과 거리를 예측하여 초기값을 갱신한다. 연속되는 다음 영상에서는 스네이크 알고리듬을 같은 방법을 사용하여 객체 영역을 추정한다. 스네이크 알고리듬은 배경과 객체를 구분하는 역할을 수행하고, 움직임 추정 알고리듬은 객체의 이동 방향과 변위를 찾아낸다. 제안된 기술은 기존의 형태모델에 기반을 둔 추적 기술에 비해 상당히 계산량이 줄기 때문에 실시간 객체 추적이 가능하며 복잡한 배경에서도 추적의 정확도를 유지하는 장점이 있다.

• Journal of Korean Neurosurgical Society
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• 제47권3호
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• pp.180-184
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• 2010

Objective : To prevent temporal depression after the pterional craniotomy, this study was designed to examine the safety and aesthetic efficacy of the brushite calcium phosphate cement (CPC) in the repair and augmentation of bone defects following the pterional craniotomy. Methods : The brushite CPC was used for the repair of surgically induced cranial defects, with or without augmentation, in 17 cases of pterional approach between March, 2005 and December, 2006. The average follow-up month was 20 with range of 12-36 months. In the first 5 cases, bone defects were repaired with only brushite CPC following the contour of the original bone. In the next 12 cases, bone defects were augmented with the brushite CPC rather than original bone contour. For a stability monitoring of the implanted brushite CPC, post-implantation evaluations including serial X-ray, repeated physical examination for aesthetic efficacy, and three-dimensional computed tomography (3D-CT) were taken 1 year after the implantation. Results : The brushite CPC paste provided precise and easy contouring in restoration of the bony defect site. No adverse effects such as infection or inflammation were noticed during the follow-up periods from all patients. 3D-CT was taken 1 year subsequent to implantation showed good preservation of the brushite CPC restoration material. In the cases of the augmentation group, aesthetic outcomes were superior compared to the simple repair group. Conclusion : The results of this clinical study indicate that the brushite CPC is a biocompatible alloplastic material, which is useful for prevention of temporal depression after pterional craniotomy. Additional study is required to determine the long-term stability and effectiveness of the brushite calcium phosphate cement for the replacement of bone.

• 한국생산제조학회지
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• 제8권1호
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• pp.100-111
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• 1999

This paper resents a discrete-time model of an edge-following with accommodation force control. Since an irregular workpiece shape causes disturbances to the system while following an edge, the use of preview control is proposed to improve the system performance. The preview control employs future information of the workpiece contour shape, and it can be developed by LQ-optimal control principles. This study provides a general method how to utilize the local future information obtained by the finite preview to minimize an optimality criterion evaluated over a problem duration. The force controller is designed based on the preview control scheme, and then implemented on a VME-based computer. Experimental results using an industrial robot show that the preview control system achieves faster tracking speed and better force regulation than the conventional nonpreview control system.

• 제어로봇시스템학회논문지
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• 제3권1호
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• pp.61-66
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• 1997

로보트 매니퓰레이터가 일정한 접촉 힘을 유지하며 공작물의 표면을 따라가게 하는 작업은 많은 자동화 생산공정에서 유용하게 이용될 수 있다. 일반적인 위치제어용 산업용 로보트를 이러한 공정에 사용하기 위해서는 접촉힘이 계측되어 로보트의 제어에 이용되어야만 한다. 이 연구는 accommodation force control 방식으로 산업용 로보트를 제어하여 edge-following에 응용하도록하며, 접촉 힘의 계측에는 wrist force sensor를 사용한다. 이 시스템의 궤도추적속도와 force regulation 등이 예견제어에 의해 향상될 수 있다. 예견제어에 의해 설계된 전체 제어 시스템은 feedback 제어기와 feedforward 예견제어기로 구성된다. 여기서, 시스템의 안정성은 feedback 제어기에 의해서 결정되며, 예견제어기는 시스템에 미치는 외란을 통제하는 것을 주 기능으로 한다. 일반적으로 선형제어 방식을 채택한 경우와 예견제어를 이용한 edge-following을 실험을 통해 비교함으로써, 예견제어의 효용성을 확인한다.

• 대한음성학회지:말소리
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• 제40호
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• pp.51-63
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• 2000

There are sentences where sentence stress is imposed on a specific word. These sentences are called 'focused sentences'. The purpose of this paper is to investigate the variation of pitch, duration, amplitude in focused words. It is noted that pitch of a focused word is higher than that of unfocused words irrespective of the accentual pattern, and that contour tones such as HL or LH are realized longer when these tones appear in focused words. Not only the noun but also the following particle like '-boda' is higher when these words are in focus. Hence pitch is proved to be the most salient prosodic feature of the focused sentence.