• CDE review
• /
• v.21 no.2
• /
• pp.27-30
• /
• 2015

Smartphone users are 15 billion in all round the world, and Korean smartphone users are estimated at 40million people to 83% of the Korean population. Selfie stick is most popular item among 20, 30's age users. And they use smartphones more than 90%. In survey they express inconvenience of using selfie stick. Inconveniences are as follows. * Heavy * Handle is inconvenient. * Mistiming during taking pictures * the range of shooting is not enough. In this paper the first improvement was that rod strength is slightly stronger. The second we divide a grip into 3 parts. If 3 parts are unfolded, these can use for tripod. We use deflection Interpretation for main Finite Elements Method program.

• Economic and Environmental Geology
• /
• v.56 no.4
• /
• pp.435-445
• /
• 2023

A delta is a depositional landform that is formed when sediment transported by a river is deposited in a relatively low-energy environment, such as a lake, sea, or a main channel. Among these, a delta formed at the confluence of rivers has a great importance in river management and research because it has a significant impact on the hydraulic and sedimentological characteristics of the river. Recently, the equilibrium state of the confluence area has been disrupted by large-scale dredging and construction of levees in the Nakdong River. However, due to the natural recovery of the river, the confluence area is returning to its pre-dredging natural state through ongoing sedimentation. The time-series data show that the confluence delta has been steadily growing since the dredging, but once it reaches a certain size, it repeats growth and retreat, and the overall size does not change significantly. In this study, we developed a model to explain the sedimentation-erosion processes in the confluence area based on the assumption that the confluence delta reaches a dynamic equilibrium. The model is based on two fundamental principles: sedimentation due to supply from the tributary and erosion due to the main channel. The erosion coefficient that represents the Nakdong River confluence areas, was obtained using data from the tributaries of the Nakdong River. Sensitivity analyses were conducted using the developed model to understand how the confluence delta responds to changes in the sediment and water discharges of the tributary and the main channel, respectively. We then used annual average discharge of the Nakdong River's tributaries to predict the dynamic equilibrium positions of the confluence deltas. Finally, we conducted a simulation experiment on the development of the Gamcheon-Nakdong River delta using recorded daily discharge. The results showed that even though it is a simple model, it accurately predicted the dynamic equilibrium positions of the confluence deltas in the Nakdong River, including the areas where the delta had not formed, and those where the delta had already formed and predicted the trend of the response of the Gamcheon-Nakdong River delta. However, the actual retreat in the Gamcheon-Nakdong River delta was not captured fully due to errors and limitations in the simplification process. The insights through this study provide basic information on the sediment supply of the Nakdong River through the confluence areas, which can be implemented as a basic model for river maintenance and management.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.11
• /
• pp.690-696
• /
• 2017

Various types of alternative energy sources to petroleum are being developed both domestically and internationally as clean energy that does not emit greenhouse gases. In particular, offshore wind power has been studied because the wind resources are relatively limitless and the wind power is relatively smaller than onshore. In this study, to analyze the scour phenomenon around offshore wind foundations, mono pile and tripod pile foundations were simulated using a FLOW-3D model. The scour phenomenon was evaluated for mono piles: one is a pile with a 5 m diameter and d=1.69 m and the other is a pile with a 5 m diameter. Numerical analysis showed that in the latter, the falling-flow increased and the maximum scour depth occurred more than 1.7 times. For a tripod pile foundation, the measured velocity and the maximum wave condition were applied to the upstream boundary condition, respectively, and the scour phenomenon was evaluated. When the maximum wave condition was applied, the maximum scour depth occurred more than about 1.3 times. When the LES model was applied, the scour depth reached equilibrium, whereas the numerical results of the RNG model show that the scour phenomenon occurred in the entire boundary area and the scour depth did not reach equilibrium. To evaluate the scour phenomenon around offshore wind foundations, it is reasonable to apply the wave condition and the LES turbulence model to numerical model applications.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 2003.08a
• /
• pp.158-163
• /
• 2003

한반도 서ㆍ남해안은 크고 작은 만과 해빈, 삼각주, 하구, 조간대 등 다양한 연안해역이 잘 발달 되어 있다 평균조차는 서해안 남부에서 약 3m로 북쪽으로 갈수록 증가하여 군산 부근에 6m, 인천 부근에서 약 8m에 달하며, 남해안의 평균조차는 부산 1.2m, 진해 2.1m, 충무 2.6m, 삼천포 3.0m, 여수 3.3m, 완도 3.5m, 목포 3.7m로 조석 간만의 차가 크게 나타나서 연안해역에 폭넓은 조간대가 형성되어 있다. (중략)

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2000.04a
• /
• pp.724-727
• /
• 2000

Rapid Prototyping(RP)이란 3차원 솔리드 모델을 단면화한 뒤 하나씩 적층하는 가공방식을 총칭한다. 이때 단면화하는 방법에 따라서 uniform, adaptive slicing으로 나뉘며, 입력 모델에 따라서 direct slicing과 STL을 이용한 방식으로 나뉜다. 적층 방법에 따라서는 연속된 2D 윤곽을 기반으로 적층하는 vertical layer 방식과 인접한 두 개의 2D 윤곽들을 연결하며 만들어진 3D layer를 기반으로 가공하는 sloping layer방식으로 나뉠 수 있다. 현재 상용 RP 시스템들에서는 거의 모든 경우 vertical layer 방식이 채택되어 사용되고 있다. RP와 절삭 공정, 예를 들면 CNC 밀링의 장점을 효율적으로 결합하기 위해서는 임의의 복잡한 형상을 갖는 솔리드 모델을 정밀도에 제한이 없이 제조할 수 있어야 한다. 그러나 절삭 공정은 특별한 전문적 지식들을 필요로 한다 또한 상용 RP에서 사용하는 순차적인 적층 작업으로는 가공할 수 없는 형상들이 많다. 대표적인 것으로 지지대를 필요로 하는 형상들이 있다. 이러한 형상들을 지원하기 위해서는 복잡한 3D 형상을 절삭 가능한 형식으로 분할하는 것과 적층 가능한 순서대로 공정 계획하는 것이 필요하게 된다. 본 연구에서는 SDM에서 제시된 3D 분할 방법이 솔리드 모델을 기반으로 전개되어 STL file과 같은 삼각다면체 형식으로 근사화된 모델에 적용하기 어렵다는데 착안하여 STL file에서 읽어들인 삼각 다면체 모델을 가공 가능한 3D 형상으로 분할하는 알고리즘을 제시하고자 한다.

• 한국해양학회지
• /
• v.19 no.1
• /
• pp.82-88
• /
• 1984

The Gwangyang Bay, southern coast of Korea, is characterized by its semi-enclosed basin morphology and mesotidal regime. The Seomjin River, in particular, has a complex delta depositional system at its mouth, which has approximately 44$\textrm{km}^2$ in the total surface area. Various sedimentary environments, such as delta, intertidal flat, subtidal zone and major tidal channels are recognized based on sediment facies and depositional regime. However, the essential intertidal flat environments are developed mainly in the western parts of the bay which is generally low in energy, i, e. tidal current and wave action.

• Spatial Information Research
• /
• v.12 no.4 s.31
• /
• pp.371-382
• /
• 2004

Continuously Operating Reference Stations (CORS) provides GPS measurements to support high accuracy CPS positioning. The CORS improves GPS positioning productivity by eliminating the requirement for GPS users to operate two receivers. Previously, this is achieved by providing data from CORS to users in post-mission mode. However, the efficiency of the CORS will be maximized by upgrading it in real-time operation using RTK-GPS surveying because users can obtain centimeter-level accuracy in real-time without operating their own reference stations. In this research, authors extracted the arbitrary point's coordinate which is using GPS CORS data, now served in RINEX FORMAT via Internet, with observation network of the existing triangulation and GPS CORS data. And then, RTK GPS was performed with this arbitrary point as reference station.

• Journal of the Korea Society of Computer and Information
• /
• v.12 no.3
• /
• pp.67-73
• /
• 2007

This paper presents a panoramic reference image generation based automatic algorithm for moving objects detection robust to illumination variations under moving camera. Background image is generated by rotating the fixed the camera on the tripod horizontally. aligning and reorganizing this images. In generation of the cylindrical panoramic image, most of previous works assume the static environment. We propose the method to generating the panoramic reference image from dynamic environments in this paper. We develop an efficient approach for panoramic reference image generation by using accumulated edge map as well as method of edge matching between input image and background image. We applied the proposed algorithm to real image sequences. The experimental results show that panoramic reference image generation robust to illumination variations can be possible using the proposed method.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.7 no.8
• /
• pp.1785-1791
• /
• 2003

This paper presents the mosaic method that the video sequence with shift and rotation information after Mellin Transform. The results are used to compute the projection matrix for each image registration. So before registration, we process camera calibration in order to reduce the image warp by camera and then compute the global projection matrix for image registration for reducing errors from rut image to last image. This paper describes the mosaic method that compute duplication and movement information quickly and robust noise using projection matrix on Mellin Transform.

• Journal of Korea Multimedia Society
• /
• v.3 no.1
• /
• pp.34-40
• /
• 2000

'[n this paper, we propose an efficient multi-view image coding algorithm which finds the optimal texture from a restricted number of multi-view image. The X-Y plane of the normalized object space is divided into the triangular patches. The depth of each node is determined by appling a block based disparity compensation method. Thereafter the texture of each patch is extracted by appling an affine transformation based disparity compensation method to the multi-view images. We reduced the number of images needed to determine the texture compared to traditional methods which use all the multi-view image in the texture extraction. The experimental results show that the SNR of images encoded by the proposed algorithm is better than that of images encoded by the traditional method by the approximately 0.2dB for the test sets of multi -view image called dragon, santa, city and kid. Image data recovered after encoding by the proposed method show a better visual results than after using traditional method.