• 구강회복응용과학지
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• 제19권2호
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• pp.105-108
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• 2003

After stage-two surgery, the highest incidence of failure has been attributed to implant overload. However, the biomechanical factors cited inthe literature that contribute to implant overload, such as bone type, cuspal inclination, horizontal offset, maxillary compared to mandibular arch, the inclusion of natural teeth within the prosthesis, and occlusal harmony are superimposed on physiologic variations. Following two cases, including reduction of cuspal inclination and usage of modified incisal pin, showed a method of contouring occlusal surface for reduction of unpreditable implant overload.

• 한국정밀공학회지
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• 제23권2호
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• pp.191-198
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• 2006

Dieless CNC forming is an innovative technology which can form various materials with complex shape by numerically controlled incremental forming process. In this paper, a method of NC tool path generation based on an STL file for dieless CNC forming is proposed. Tool trajectory adopts the principle of layered manufacturing in rapid prototyping technology, but it is necessary to consider STL offset because of the ball shaped tool with a radius. Vertex offset method which enables to compute offset STL directly is engaged for STL offset. The offseted STL is sliced by cutting planes to generate contouring tool path. Algorithm is implemented on a computer and experimented on a dieless CNC forming machine to show its validity.

• 대한기계학회논문집A
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• 제24권1호
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• pp.173-181
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• 2000

Depending upon the method of the surface generation and the quality of the boundary curves provided, the resulting surfaces may have global or local irregularities in many cases. Thus it would be necessary for the designer to evaluate the surface quality and to modify the surface. This capability is very important because the defect of the surface requires the rework of the dies that causes a big loss in cost and delivery time. To simulate the reflection line test in the actual production line, a faster generation algorithm is presented. Among., various surface interrogation methods using reflection lines, Blinn-Newell type of reflection mapping is applied to generate reflection lines on the trimmed NURBS surface. The generation of reflection lines is formulated as a surface-plane intersection problem, and solved by surface-contouring techniques. In addition, a modified reflection map is proposed to eliminate the discontinuity of reflection lines due to the configuration of the reflection map. A fast reflection line algorithm is developed utilizing an efficient traced contouring technique, and proved to be well suited for real-time quality-assessment task.

• Archives of Plastic Surgery
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• 제45권4호
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• pp.319-324
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• 2018

Perforator flaps are becoming increasingly common, and as primary thinning techniques are being developed, the need for secondary contouring of flaps is decreasing. However, many reconstructive flap procedures still incorporate secondary debulking to improve the functional and aesthetic outcomes. Direct excision, liposuction, tissue shaving with an arthroscopic cartilage shaver, and skin grafting are the four major methods used for secondary debulking. Direct excision is primarily applied in flaps where the skin is redundant, even though the volume is not excessive. However, due to the limited range of excision, performing a staged excision is recommended. Liposuction can reduce the amount of subcutaneous tissue of the flap and protect the vascular pedicles. However, the main drawback of this method is its limited ability to remove fibrotic tissues, for which the use of a shaver may be more convenient. The main drawback of using a shaver is that it is difficult to simultaneously remove excess skin. Skin grafting enables the removal of sufficient excess tissue to recover the contour of the normal limb and to improve the color match, facilitating excellent aesthetic results.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.173-176
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• 2008

Lake studies play an important role in water management, ecology, and other environmental issues. Typically, monitoring lake levels is the first step on the lake studies. However, for the Prairie Pothole Region (PPR) of North America having millions of small lakes and potholes, on-site measurement for lake levels is almost impossible with the conventional gage stations. Therefore, we employed Geographic Information System (GIS) and remote sensing approach with the Shuttle Radar Topography Mission data to extract lake levels. Several image processing techniques were used to extract lake levels for January, 2000 as a one-time snapshot which will be useful in historic lake level reconstruction. This study is associated with other remote sensing datasets such as Landsat imagery and Digital Orthophoto Quadrangle (DOQ). In this research, firstly, image processing techniques like FFT filtering, Lee-sigma, masking with Canny Edge Detector, and contouring were tested for lake level estimation. The semi-automated contouring technique was developed to accomplish the bulk processing for large amount of lakes in this region. Also, effectiveness of each method for bulk processing was evaluated.

• 전자공학회논문지SC
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• 제37권1호
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• pp.10-18
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• 2000

본 논문에서는 2축 서보시스템에 적용하기 위한 새로운 윤곽 모델링을 이용하여 퍼지논리형 상호결합제어기를 제안한다. 일반적인 각 축 독립제어기는 각 축의 동적 변수와 루프 이득의 불일치로 인해 윤곽 성능을 감소시킨다. 실제적으로 이러한 시스템은 많은 불확실성도 보유하고 있다. 상호결합제어기는 정확한 윤곽을 구하기 위해 모든 축의 위치 오차 정보를 동시에 이용한다. 그러나 일반적인 상호결합제어기는 마찰, 백래쉬 그리고 매개변수 변화를 극복하지 못한다. 또한 정확한 다축 시스템의 수학적 모델을 얻기 힘들기 때문에 서보시스템의 퍼지논리형 상호결합제어기를 제안한다. 이와 더불어 새로운 윤곽 오차 벡터 계산법을 제시한다. 제안한 알고리즘의 성능을 검증하기 위해 실험결과를 나타낸다.

• 대한조선학회논문집
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• 제52권1호
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• pp.70-76
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• 2015

The ship hull is accomplished by assembling various curved surfaces. There are numerous existing methods for ship hull processing, which need certain appropriate processing methods to enable it to be more efficient. The curved hull plates can be divided into convex region and saddle region. It is common to use line heating method to form a saddle region, when it comes to a convex region, it will be triangle heating method to be utilized. A precise analysis for curvature domain is required for the application of proper processing method. There exist various problems on existing calculation methods of curvature domain. Therefore, a more powerful method is demanded to it more accurately. In this study, a method called Dual Contouring is applied to extract curved surfaces, which is able to improve accuracy of extracted area. Based on all above, a best-suited heat processing method should be selected.

• 대한기계학회논문집A
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• 제28권1호
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• pp.40-47
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• 2004

This paper proposes a three-axis coupling controller designed to improve the contouring accuracy in machining of 3D nonlinear contours. The proposed coupling controller is based on an innovative 3D contour error model and a PID control law. The novel contour error model provides almost exact calculation of contour errors in real-time for arbitrary contours and can be integrated with any type of existing interpolator. In the proposed method, three axes of motion are coordinated by the proposed coupling controller along with a proportional controller for each axis. The proposed contour error model and coupling controller are evaluated through computer simulations. The simulation results show that the proposed 3-axis coupling controller with the new contour error model substantially can improve the contouring accuracy by order of magnitude compared with the existing uncoupled controllers in high-speed machining of nonlinear contours.

• 한국정밀공학회지
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• 제21권4호
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• pp.64-71
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• 2004

The growing need for higher precision and productivity in manufacturing industry has lead to an increased interest in computer numerical control (CNC) systems. It is well known fact that the cross-coupling controller (CCC) is an effective method for contouring applications. In this paper, a multi-axis contour error controller (CEC) based on a contour error vector using parametric curve interpolator is introduced. The contour error vector is a vector from the actual tool position to the nearest point on the desired path. The contour error vector is the closest error model to the contour error. The simulation results show that the CEC is more accurate than the conventional CCC for a biaxial motion system. In addition, the experimental results on 3-axis motion system show that the CEC is simply applied to 3-axis motions and contouring accuracy is significantly improved.

• 산업기술연구
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• 제15권
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• pp.23-32
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• 1995

The methodology of automatic generation of tool path for rough cutting of a sculptured surface is proposed with the improved contouring method, unequal level line machining. Considering the surface shape and the diameter of the endmill, the distance between level lines is obtained. To improve MMR, initial rough cutting is processed with the large diameter endmill and the remained material is removed by the relatively small diameter endmill. Tool path is generated from the offset curve of respective level line and the interferences between the tool and workpiece are automatically avoided. After generating NC part program, the sculptured surface is machined at the vertical machining center. From the experimental results, total cutting length and machining time are reduced more effectively than conventional contouring methods.