• Transactions of the Korean Society of Mechanical Engineers
• /
• v.10 no.4
• /
• pp.463-470
• /
• 1986

본 연구에서는 절삭공정 중 발생하는 공구의 접촉이탈 현상에 의하여 공작 물의 절삭된 표면중에 한회전 및 그 이전 회전에 절삭된 절삭면의 형상이 현재의 절삭 깊이에 영향을 미치는 다중재생효과(multiple regenerative effect)가 존재하는 선삭 작업에서 공구의 착탈현상을 고려한 비선형채터(nonlinear chatter)를 공작기계의 생 산성의 관점에서 절삭공정의 특성을 고려하여 해석하였으며, 수동제어기의 일종인 임 펙트댐퍼를 절삭공정에 응용하여 절삭작업중에 공작기계의 안정성향상 뿐만 아니라 생 산성의 증가효과를 규명하였다.아울러 댐퍼자체의 설계변수에 따른 채터 억제효과 를 고려하여 최적의 댐퍼를 설계하는 방법을 제시하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1993.04b
• /
• pp.76-80
• /
• 1993

절삭가공중에서 DRILL가공은 일반기계가공 공정중에 23 .approx. 25% 정도의 비율을 점우하고 있는 중요한 위치의 작업의 하나이고 또한 요구되는 정밀도를 만족하기 어렵고, 높은 생산성이 요구되는 가공법이다. 기계가공의 무인화, 자동화, 고능률화 및 정도향상 이라는 측면에서 더욱 이에 대응할 수 있는 가공방법 즉 공작물, 공구재료, 공구형상 및 절삭조건등에 걸쳐 광범위하게 연구개발 되어 져 가고 있다. 이 작업중 특히 곤란한 것은 깊은 구멍가공(DEEP HOLE DRILL)으로서 깊이/직경의 비가 극히 높은(약 5배이상) 절삭가공 의 경우에는 CHIP의 배출, 절삭날부의 윤활, 공구의 진동등의 문제로 인하여 일반적인 절삭가공 공법으로는 가공이 여려운 경우가 많다. 본 연구는 Solid BTA Drill(Mlti-tip Drill Head with Brazed Tips)에 의하여 가공에요구되는 절삭성 분석과 절삭조건의 변화에 따른 공작물의 가공정도 즉, 가공구멍의 직경의 변화, 표면거칠기. 진원도의 변화상태 및 공구의 마모된 현상에 대하여 실험조사하여 공구에 제한된 수명을 연장하고, 제품에 요구되는 품질수준을 확보하는가에 대하여 본 실험을 통하여 분석하도록 하였다.

• Proceedings of the KAIS Fall Conference
• /
• 2010.05b
• /
• pp.1159-1162
• /
• 2010

연약지반 문제를 해결하기 위한 방안으로 세계 각국에서 연약지반 개량공법의 하나인 연직배수공법이 주로 사용되고 있다. 연직배수공법은 연약한 점성토 지반 내에 인공적으로 연직 배수재을 다수 설치하여 배수거리를 단축시킴으로써 압밀을 촉진시키고, 그에 따른 강도증가 효과를 얻을 수 있는 공법이다. 연직배수재로 경제성과 시공성이 우수한 PBD가 널리 사용되고 있다. PBD 시공품질은 시공 깊이, 압력, 수직도 등에 영향을 받을게 된다. 본 논문에서는 PBD 시공시 배수재의 시공 심도, 압력, 수직도를 자동측정하여 작업자가 실시간으로 모니터링 할 수 있고 시공결과를 자동 저장하는 시스템을 개발하였다. 개발된 시스템은 시공 불량 요인이 발생시 자동 경고하여 불량률을 줄일 수 있고, 장비의 이상 발생시 자동 제어시스템을 가동하여 작업의 안전성을 확보하도록 하였다.

• Smart Media Journal
• /
• v.1 no.3
• /
• pp.36-42
• /
• 2012

Recently, the smart applications, such as smart phone and smart TV, become a hot issue in IT consumer markets. In particular, the smart TV provides 3D video services, hence efficient coding methods for 3D video data are required. Three-dimensional (3D) video involves stereoscopic or multi-view images to provide depth experience through 3D display systems. Binocular cues are perceived by rendering proper viewpoint images obtained at slightly different view angles. Since the number of viewpoints of the multi-view video is limited, 3D display devices should generate arbitrary viewpoint images using available adjacent view images. In this paper, after we explain a view synthesis method briefly, we propose a new algorithm to compensate view synthesis errors around object boundaries. We describe a 3D warping technique exploiting the depth map for viewpoint shifting and a hole filling method using multi-view images. Then, we propose an algorithm to remove boundary noises that are generated due to mismatches of object edges in the color and depth images. The proposed method reduces annoying boundary noises near object edges by replacing erroneous textures with alternative textures from the other reference image. Using the proposed method, we can generate perceptually inproved images for 3D video systems.

• Korean Journal of Construction Engineering and Management
• /
• v.21 no.1
• /
• pp.78-86
• /
• 2020

Dozer is an expensive construction equipment and has a significant performance impact on earthwork performance. A machine guidance system has been applied to dozer equipment as a solution that can improve the performance. The system can provide earthwork-related information to equipment operators so that earthworks can be carried out with minimum support from surveyors. Construction Equipment Machine guidance has the function of supporting earthwork according to an earthwork plan by providing excavation-related information to machine operators. The objective of this study is to evaluate the performance improvement of a machine guidance system for an dozer earthwork operation, and to compare the machine guidance method with the traditional method. The performance has been evaluated in two folds: 1) productivity and 2) accuracy. The productivity shows the quantity of earthwork for a given unit time. The accuracy shows the deviation of grading level from the designed level on the construction drawing for earthwork. The machine guidance system has been applied to a testing bed in a construction site. Data comparison analysis showed that the earth earthwork had 46.59% improvement in productivity as well as 46.96% improvement in accuracy, and is expected to provide a tool for applying smart constrction to the earthwork operation.

• Journal of the Korean Geotechnical Society
• /
• v.35 no.12
• /
• pp.101-109
• /
• 2019

The bucket platform is a new structure suitable for construction of offshore bridge foundations and providing the temporary support for equipments and labour. The platform can be subjected to moment loading due to the eccentric loading or the horizontal load by wave and wind. Therefore, a three dimensional finite element analysis was performed to evaluate the moment bearing capacity of the bucket platform, varying soil density, the diameter and embedment depth of the bucket. The numerical modeling was verified and compared with the moment-rotation curve from a field loading test. The uniform sandy ground was assumed and the moment load was applied at the top plate of the platform, increasing bucket rotation. The moment-rotation relations were analyzed to determine the moment capacity, which was influenced by the embedment depth and diameter of the bucket. Finally, a preliminary design equation was suggested to estimate the moment bearing capacity.

• Journal of Digital Contents Society
• /
• v.13 no.2
• /
• pp.235-245
• /
• 2012

This paper introduce a quiz game contents based on gesture interface. We analyzed the off-line quiz games, extracted its presiding components, and digitalized them so that the proposed game contents is able to substitute for the off-line quiz games. We used the Kinect camera to obtain the depth images and performed the preprocessing including vertical human segmentation, head detection and tracking and hand detection, and gesture recognition for hand-up, hand vertical movement, fist shape, pass and fist-and-attraction. Especially, we defined the interface gestures designed as a metaphor for natural gestures in real world so that users are able to feel abstract concept of movement, selection and confirmation tangibly. Compared to our previous work, we added the card compensation process for completeness, improved the vertical hand movement and the fist shape recognition methods for the example selection and presented an organized test to measure the recognition performance. The implemented quiz application program was tested in real time and showed very satisfactory gesture recognition results.

• Korean Journal of Cognitive Science
• /
• v.27 no.3
• /
• pp.355-376
• /
• 2016

We used holes defined by color similarity (Experiment 1) and binocular disparity (Experiment 2) to study how the inner contour of an object (i.e., boundary of a hole in it) is encoded in visual working memory. Many studies in VWM have shown that an object's boundary properties can be integrated with its surface properties via their shared spatial location, yielding an object-based encoding benefit. However, encoding of the hole contours has rarely been tested. We presented objects (squares or circles) containing a bar under a change detection paradigm, and relevant features to be remembered were the color of objects and the orientation of bars (or holes). If the contour of a hole belongs to the surrounding object rather than to the hole itself, the object-based feature binding hypothesis predicts that the shape of it can be integrated with color of an outer object, via their shared spatial location. Thus, in the hole display, change detection performance was expected to better than in the conjunction display where orientation and color features to be remembered were assigned to different parts of a conjunction object, and comparable to that in a single bar display where both orientation and color were assigned into a single bar. However, the results revealed that performance in the hole display did not differ from that in the conjunction display. This suggests that the shape of holes is not automatically encoded together with the surface properties of the outer object via object-based feature binding, but encoded independently from the surrounding object.

• Archives of design research
• /
• v.15 no.1
• /
• pp.359-368
• /
• 2002

Fabric art is most distinguished field among the Modern art. Among them, tapestry which begins human history is investigated more and more deeply and till now it displays with various type and exhibition. But, because of the huge scale of the working process, it requires much time and hard endeavor. After sampling, it begins main process in the present situation. But we cannot know exactly whether it goes well or not until it ends. So after fulfilled whole process, we often try new work again. Because of this reason, we devise computer simulation. With computer simulation we can preview whole working and lengthen the planning time, shorten the needless time. Simulation is made up of Scan, Drawing, Line clean up, Rendering, Parity, and Printing. Scan and Drawing can male new idea. And during the Line clean up we can make vector image and modify the image. And then rendering the image and inquiring the length and weight of yarn. Last process is printing an then making a package soft ware by means of prototype. Through these process, many producers and student can easily access to tapestry and reduce the needless time and endeavor.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.6
• /
• pp.464-469
• /
• 2017

This study evaluated the displacements of a Cu bar in the Y-direction and the relationship between swaging pressures and total contact forces to increase the productivity of the rotor core swaging process. Elastic-plastic numerical analyses of four different Cu bar shapes were performed with a constant swaging pressure to evaluate the displacements of the Cu bar in the Y-direction and the contact force distributions at the contact surfaces during the swaging process. Based on the numerical analysis results, the following conclusions were obtained. First, a simplified 2-dimensional cyclic symmetric analysis model was developed for the numerical analysis of the rotor core swaging process. Second, the final displacements of the Cu bar in the Y-direction were nearly the same as the change of the Cu bar size at a constant swaging pressure. Third, a linear relationship between the swaging pressures and the total contact forces, the so called resistance forces, was suggested.